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1xINTERNET blog: Everything you need to know about The European Accessibility Act (EAA)

Planet Drupal - Mon, 2024-08-05 04:19

The European Accessibility Act (EAA) aims to enhance the accessibility of products and services for people with disabilities and the elderly throughout the EU. With less than a year remaining to meet compliance requirements, both the public and private sectors must act now.

Categories: FLOSS Project Planets

Zato Blog: API development workflow with Zato

Planet Python - Mon, 2024-08-05 04:00
API development workflow with Zato 2024-08-05, by Dariusz Suchojad

Zato is an integration platform and backend application server which means that, during most of their projects, developers using Zato are interested in a few specific matters.

The platform concentrates on answering these key, everyday questions that Python backend developers routinely ask:

  • How do I connect to external systems or databases to store or extract data?
  • How do I map messages from one format to another?
  • How do I automate my work so that it is repeatable across environments?
  • How can I focus on my job instead of thinking of trivial low-level details?
  • How do I debug my code?
  • How can I reuse the skills and knowledge that I obtained elsewhere and how can I better myself?
  • How do I manage the complexity of having to integrate at least several systems and dozens or hundreds of APIs?
The typical workflow

Dashboard

  • Dashboard is a web-based administration console that lets you define all the various connection pools, security types, scheduler jobs or other integration assets that you later make use of in your Python-based API services

  • When you install Zato, it is comfortable to use its Dashboard to define resources like REST, MongoDB or SOAP connections pools because it does not require any programming, you just fill out a form and that resource is created

Python

  • All of your code is in Python - that makes it easy to manipulate any kind of data that you receive or may need to access

  • In your code, you only deal with the business logic - if your service is invoked, it means that all the security layers, serializers and other low-level parts have already completed their job and you are given a nice Python-based business object that represents your input. Based on this input information, you create output that your business logic dictates, still working purely on a high-level of Python objects, without any low-level details.

  • Static typing is encouraged through the use of dataclasses for your data models

  • Your code is hot-deployed from your IDE, no matter where your servers are, e.g. you work on Mac but the server is a remote Linux instance

  • You can debug your services from your IDE as well and, again, the server can be a remote one

# -*- coding: utf-8 -*- # stdlib from dataclasses import dataclass # Zato from zato.server.service import Model, Service @dataclass(init=False) class GetClientRequest(Model): client_id: int @dataclass(init=False) class GetClientResponse(Model): name: str email: str segment: str class GetClient(Service): class SimpleIO: input = GetClientRequest output = GetClientResponse def handle(self): # Enable type checking and type completion request = self.request.input # type: GetClientRequest # Log details of our request self.logger.info('Processing client `%s`', request.client_id) # Produce our response - in a full service this information # will be obtained from one or more databases or systems. response = GetClientResponse() response.name = 'Jane Doe' response.email = 'hello@example.com' response.segment = 'RNZ' # Return the response to our caller self.response.payload = response

Such a service can be assigned to one or more REST channels and we can invoke it now:

$ curl localhost:17010/api/v1/client -d '{"client_id":123}' {"name":"Jane Doe","email":"hello@example.com","segment":"RNZ"} $ Automation

  • Using Dashboard is very handy, and, once you are satisfied with what you created using it, the resources can be exported from command line using a built-in tool called enmasse - the result is a regular YAML file that describes every resource that you created using Dashboard

  • In the next step, an emasse file can be imported in a new environment, also from command line. For instance, you can keep adding new connection definitions to the export file each day and they can be imported in a separate testing environment by CI/CD regression testing processes.

  • Thanks to the enmasse export and import cycle, you do not need to manually recreate any resources that you initially created in your development environment. Moreover, because enmasse files are simple YAML files, you can script their usage in any way required when they are being import, e.g. by filling out credentials or other details that each environment may differ by.

  • Similarly, with your Python code, you can commit your code to git and configure each environment to hot-deploy it directly from a git checkout. Alternatively, Python code can be deployed statically, which requires a server restart. The latter approach is useful when you, for instance, prepare an AWS AMI with your solution that you create new runtime instance from, because it lets you embed your entire enmasse definition and code directly in your AMIs.

OpenAPI

  • Definitions of your services can be exported to OpenAPI

  • Note that, by default, your services can be multi-protocol - it means that you may have a service that only uses WebSockets, or perhaps is a background one that has no REST endpoint at all, and yet, you still will be able to export it to OpenAPI

  • Taken together, it means that you can use any OpenAPI-compatible tool, such as Postman, for accessing and testing your API services, no matter if they use REST or not

  • You can also generate an entire static HTML site that will include OpenAPI as well as static pages describing your APIs - this is useful, for instance when you need to share with your tech partners not only an OpenAPI definition but a pretty-looking API documentation site as well

Let's generate an OpenAPI definition for the GetClient service above:

$ zato openapi /path/to/server/server1 \ --include "client*" \ --file /tmp/openapi.yaml

Now, we can import the OpenAPI definition to Postman and invoke our services from it:

Python once more

  • Python is at the core of Zato and the platform allows you to leverage your already existing skills and knowledge of third-party libraries

  • For instance, the code below is a stand-alone program that connects to Redis to insert a key and read it back:

# -*- coding: utf-8 -*- # Redis import redis # Connect to the database conn = redis.Redis(host='localhost', port=6379, db=0) # Set a key .. conn.set('key', 'value') # .. read it back .. result = conn.get('key') # .. and log what we received. print('Result', result)
  • Now, the same as a Zato-based service:
# -*- coding: utf-8 -*- # Zato from zato.server.service import Service class MyService(Service): def handle(self): # Set a key .. self.kvdb.conn.set('key', 'value') # .. read it back .. result = self.kvdb.conn.get('key') # .. and log what we received. self.logger.info('Result %s', result)

  • In both cases, it is exactly the same amount of code yet a couple of differences are notable.

    • First, because the configuration was created earlier using Dashboard or enmasse, your code does not need to be concerned with where Redis is, it just makes use of it.
    • Second, already at this point, your Zato code is a scalable API service that can be hot-deployed to clusters for other systems to invoke it.
    • Yet, the actual business logic, the usage of Redis, is the same, which means that you can reuse what you already know and build upon it while developing with Zato.

  • Redis was but one example and the same principle applies to everything else. Be it SQL, MongoDB, ElasticSearch or any other connection type, you can take your existing code and simply embed it in Zato services.

  • This also means that it is easy to find programming examples specific to a particular system because, in the end, when you connect to such an external system through Zato, you issue requests using a library which already is widely popular among Python programmers, like redis-py in this example above.

  • Similarly, as a data scientist you may already have some Pandas or Spark code developed earlier - the same principle applies, you can embed it in your services or you can import it from your libraries, just like with regular Python code.

More resources

➤ Python API integration tutorial
➤ What is an integration platform?
➤ Python Integration platform as a Service (iPaaS)
➤ What is an Enterprise Service Bus (ESB)? What is SOA?

More blog posts➤
Categories: FLOSS Project Planets

DrupalEasy: DrupalEasy Podcast S17E1 - Jamie Abrahams - Drupal's new AI module

Planet Drupal - Sun, 2024-08-04 15:26

We talk with Jamie Abrahams from FreelyGive about the new AI module and what it means for the future of AI modules in the Drupal ecosystem.

URLs mentionedDrupalEasy News

Audio transcript

We're using the machine-driven Amazon Transcribe service to provide an audio transcript of this episode.

Subscribe

Subscribe to our podcast on iTunes, iHeart, Amazon, YouTube, or Spotify. 

If you'd like to leave us a voicemail, call 321-396-2340. Please keep in mind that we might play your voicemail during one of our future podcasts. Feel free to call in with suggestions, rants, questions, or corrections. If you'd rather just send us an email, please use our contact page.

Credits

Podcast edited by Amelia Anello.
 

Categories: FLOSS Project Planets

Freedesktop Specs Website Update

Planet KDE - Sun, 2024-08-04 14:54

The Freedesktop.org Specifications directory contains a list of common specifications that have accumulated over the decades and define how common desktop environment functionality works. The specifications are designed to increase interoperability between desktops. Common specifications make the life of both desktop-environment developers and especially application developers (who will almost always want to maximize the amount of Linux DEs their app can run on and behave as expected, to increase their apps target audience) a lot easier.

Unfortunately, building the HTML specifications and maintaining the directory of available specs has become a bit of a difficult chore, as the pipeline for building the site has become fairly old and unmaintained (parts of it still depended on Python 2). In order to make my life of maintaining this part of Freedesktop easier, I aimed to carefully modernize the website. I do have bigger plans to maybe eventually restructure the site to make it easier to navigate and not just a plain alphabetical list of specifications, and to integrate it with the Wiki, but in the interest of backwards compatibility and to get anything done in time (rather than taking on a mega-project that can’t be finished), I decided to just do the minimum modernization first to get a viable website, and do the rest later.

So, long story short: Most Freedesktop specs are written in DocBook XML. Some were plain HTML documents, some were DocBook SGML, a few were plaintext files. To make things easier to maintain, almost every specification is written in DocBook now. This also simplifies the review process and we may be able to switch to something else like AsciiDoc later if we want to. Of course, one could have switched to something else than DocBook, but that would have been a much bigger chore with a lot more broken links, and I did not want this to become an even bigger project than it already was and keep its scope somewhat narrow.

DocBook is a markup language for documentation which has been around for a very long time, and therefore has older tooling around it. But fortunately our friends at openSUSE created DAPS (DocBook Authoring and Publishing Suite) as a modern way to render DocBook documents to HTML and other file formats. DAPS is now used to generate all Freedesktop specifications on our website. The website index and the specification revisions are also now defined in structured TOML files, to make them easier to read and to extend. A bunch of specifications that had been missing from the original website are also added to the index and rendered on the website now.

Originally, I wanted to put the website live in a temporary location and solicit feedback, especially since some links have changed and not everything may have redirects. However, due to how GitLab Pages worked (and due to me not knowing GitLab CI well enough…) the changes went live before their MR was actually merged. Rather than reverting the change, I decided to keep it (as the old website did not build properly anymore) and to see if anything breaks. So far, no dead links or bad side effects have been observed, but:

If you notice any broken link to specifications.fd.o or anything else weird, please file a bug so that we can fix it!

Thank you, and I hope you enjoy reading the specifications in better rendering and more coherent look!

Categories: FLOSS Project Planets

Matthias Klumpp: Freedesktop Specs Website Update

Planet Debian - Sun, 2024-08-04 14:54

The Freedesktop.org Specifications directory contains a list of common specifications that have accumulated over the decades and define how common desktop environment functionality works. The specifications are designed to increase interoperability between desktops. Common specifications make the life of both desktop-environment developers and especially application developers (who will almost always want to maximize the amount of Linux DEs their app can run on and behave as expected, to increase their apps target audience) a lot easier.

Unfortunately, building the HTML specifications and maintaining the directory of available specs has become a bit of a difficult chore, as the pipeline for building the site has become fairly old and unmaintained (parts of it still depended on Python 2). In order to make my life of maintaining this part of Freedesktop easier, I aimed to carefully modernize the website. I do have bigger plans to maybe eventually restructure the site to make it easier to navigate and not just a plain alphabetical list of specifications, and to integrate it with the Wiki, but in the interest of backwards compatibility and to get anything done in time (rather than taking on a mega-project that can’t be finished), I decided to just do the minimum modernization first to get a viable website, and do the rest later.

So, long story short: Most Freedesktop specs are written in DocBook XML. Some were plain HTML documents, some were DocBook SGML, a few were plaintext files. To make things easier to maintain, almost every specification is written in DocBook now. This also simplifies the review process and we may be able to switch to something else like AsciiDoc later if we want to. Of course, one could have switched to something else than DocBook, but that would have been a much bigger chore with a lot more broken links, and I did not want this to become an even bigger project than it already was and keep its scope somewhat narrow.

DocBook is a markup language for documentation which has been around for a very long time, and therefore has older tooling around it. But fortunately our friends at openSUSE created DAPS (DocBook Authoring and Publishing Suite) as a modern way to render DocBook documents to HTML and other file formats. DAPS is now used to generate all Freedesktop specifications on our website. The website index and the specification revisions are also now defined in structured TOML files, to make them easier to read and to extend. A bunch of specifications that had been missing from the original website are also added to the index and rendered on the website now.

Originally, I wanted to put the website live in a temporary location and solicit feedback, especially since some links have changed and not everything may have redirects. However, due to how GitLab Pages worked (and due to me not knowing GitLab CI well enough…) the changes went live before their MR was actually merged. Rather than reverting the change, I decided to keep it (as the old website did not build properly anymore) and to see if anything breaks. So far, no dead links or bad side effects have been observed, but:

If you notice any broken link to specifications.fd.o or anything else weird, please file a bug so that we can fix it!

Thank you, and I hope you enjoy reading the specifications in better rendering and more coherent look!

Categories: FLOSS Project Planets

Scarlett Gately Moore: KDE, Kubuntu, Debian: Weekly progress report Qt6 updates.

Planet Debian - Sun, 2024-08-04 08:35

Thankfully no tragedies to report this week! I thank each and everyone of you that has donated to my car fund. I still have a ways to go and could use some more help so that we can go to the funeral. https://gofund.me/033eb25d I am between contracts and work packages, so all of my work is currently for free. Thanks for your consideration.

Another very busy week getting qt6 updates in Debian, Kubuntu, and KDE snaps.

Kubuntu:

  • Merkuro and Neochat SRUs have made progress.
  • See Debian for the qt6 Plasma / applications work.

Debian:

  • qtmpv – in NEW
  • arianna – in NEW
  • kamera – experimental
  • libkdegames – experimental
  • kdenetwork-filesharing – experimental
  • xwaylandvideobridge – NEW
  • futuresql – NEW
  • kpat WIP
  • Tokodon – Done, but needs qtmpv to pass NEW
  • Gwenview – WIP needs kamera, kio-extras
  • kio-extras – Blocked on kdsoap in which the maintainer is not responding to bug reports or emails. Will likely fork in Kubuntu as our freeze quickly approaches.

KDE Snaps:

Updated QT to 6.7.2 which required a rebuild of all our snaps. Also found an issue with mismatched ffmpeg libraries, we have to bundle them for now until versioning issues are resolved.

Made new theme snaps for KDE breeze: gtk-theme-breeze, icon-theme-breeze so if you use the plasma theme breeze please install these and run

for PLUG in $(snap connections | grep gtk-common-themes:icon-themes | awk '{print $2}'); do sudo snap connect ${PLUG} icon-theme-breeze:icon-themes; done for PLUG in $(snap connections | grep gtk-common-themes:gtk-3-themes | awk '{print $2}'); do sudo snap connect ${PLUG} gtk-theme-breeze:gtk-3-themes; done for PLUG in $(snap connections | grep gtk-common-themes:gtk-2-themes | awk '{print $2}'); do sudo snap connect ${PLUG} gtk-theme-breeze:gtk-2-themes; done

This should resolve most theming issues. We are still waiting for kdeglobals to be merged in snapd to fix colorscheme issues, it is set for next release. I am still working on qt6 themes and working out how to implement them in snaps as they are more complex than gtk themes with shared libraries and file structures.

Please note: Please help test the –edge snaps so I can promote them to stable.

WIP Snaps or MR’s made

  • Juk (WIP)
  • Kajongg (WIP problem with pyqt)
  • Kalgebra (in store review)
  • Kdevelop (WIP)
  • Kdenlive (MR)
  • KHangman (WIP)
  • Ruqola (WIP)
  • Picmi (building)
  • Kubrick (WIP)
  • lskat (building)
  • Palapeli (MR)
  • Kanagram (WIP)
  • Labplot (WIP)
  • Ktuberling (building)
  • Ksudoku (building)
  • Ksquares (MR)
Categories: FLOSS Project Planets

KDE, Kubuntu, Debian: Weekly progress report Qt6 updates.

Planet KDE - Sun, 2024-08-04 08:35

Thankfully no tragedies to report this week! I thank each and everyone of you that has donated to my car fund. I still have a ways to go and could use some more help so that we can go to the funeral. https://gofund.me/033eb25d I am between contracts and work packages, so all of my work is currently for free. Thanks for your consideration.

Another very busy week getting qt6 updates in Debian, Kubuntu, and KDE snaps.

Kubuntu:

  • Merkuro and Neochat SRUs have made progress.
  • See Debian for the qt6 Plasma / applications work.

Debian:

  • qtmpv – in NEW
  • arianna – in NEW
  • kamera – experimental
  • libkdegames – experimental
  • kdenetwork-filesharing – experimental
  • xwaylandvideobridge – NEW
  • futuresql – NEW
  • kpat WIP
  • Tokodon – Done, but needs qtmpv to pass NEW
  • Gwenview – WIP needs kamera, kio-extras
  • kio-extras – Blocked on kdsoap in which the maintainer is not responding to bug reports or emails. Will likely fork in Kubuntu as our freeze quickly approaches.

KDE Snaps:

Updated QT to 6.7.2 which required a rebuild of all our snaps. Also found an issue with mismatched ffmpeg libraries, we have to bundle them for now until versioning issues are resolved.

Made new theme snaps for KDE breeze: gtk-theme-breeze, icon-theme-breeze so if you use the plasma theme breeze please install these and run

for PLUG in $(snap connections | grep gtk-common-themes:icon-themes | awk '{print $2}'); do sudo snap connect ${PLUG} icon-theme-breeze:icon-themes; done for PLUG in $(snap connections | grep gtk-common-themes:gtk-3-themes | awk '{print $2}'); do sudo snap connect ${PLUG} gtk-theme-breeze:gtk-3-themes; done for PLUG in $(snap connections | grep gtk-common-themes:gtk-2-themes | awk '{print $2}'); do sudo snap connect ${PLUG} gtk-theme-breeze:gtk-2-themes; done

This should resolve most theming issues. We are still waiting for kdeglobals to be merged in snapd to fix colorscheme issues, it is set for next release. I am still working on qt6 themes and working out how to implement them in snaps as they are more complex than gtk themes with shared libraries and file structures.

Please note: Please help test the –edge snaps so I can promote them to stable.

WIP Snaps or MR’s made

  • Juk (WIP)
  • Kajongg (WIP problem with pyqt)
  • Kalgebra (in store review)
  • Kdevelop (WIP)
  • Kdenlive (MR)
  • KHangman (WIP)
  • Ruqola (WIP)
  • Picmi (building)
  • Kubrick (WIP)
  • lskat (building)
  • Palapeli (MR)
  • Kanagram (WIP)
  • Labplot (WIP)
  • Ktuberling (building)
  • Ksudoku (building)
  • Ksquares (MR)
Categories: FLOSS Project Planets

git bisecting kernel: some pitfalls

Planet KDE - Sat, 2024-08-03 20:00
I like to call myself git “expert”, but I failed pretty badly few weeks ago I needed to bisect the kernel source code to figure out one bug. General git bisect process is, You have two known commits, one is good and one is bad, and you keep searching for bad commit by splitting history in two. Lets say you have following changelog (not the actual changelog I was debugging, but example):
Categories: FLOSS Project Planets

KStars 3.7.2 Released

Planet KDE - Sat, 2024-08-03 15:45
KStars v3.7.2 is released on 2024.08.03 for Windows, MacOS & Linux. It's a bi-monthly bug-fix release with a couple of exciting features.
A few members of the KStars development team were enjoying their summer holidays over the past few weeks, but we still have a couple of exciting features in this release!
Multi-Camera SupportWolfgang Reissenberger devoted countless hours to bring this complex feature that required lots of architectural changes in Ekos. If you have double rigs (or even more), we have a new great feature: multi camera support! If you have more than one optical train on your mount, you now will be able to run capture sequences for each of your optical trains in parallel from the same KStars instance. You simply need to create an optical train for each of your telescopes on your mount, create camera tabs for each optical train, create their own sequence and let them run in parallel.


This new feature may also be used in combination with the scheduler: in this release, the scheduler itself will control the first camera. On top of that, you could configure additional cameras in the capture tab which could execute their own capture sequences. Enhancing the scheduler such that it could control multiple optical trains in parallel is already under development and will be part of one of the next releases. So stay tuned!
Focus Advisor v4
John Evans refactored the Focus Advisor to make it simpler while still offering a lot of insight on parameters tuning. It is now more accessible to new users and has added functionality to optimize values for 2 of the more difficult Focus parameters: Step Size and Backlash (or AF Overscan).



In addition, Focus Advisor contains a convenience tool to locate stars by searching the range of motion of the focuser and another convenience tool to highlight differences between current Focus parameter settings and those recommended by Focus Advisor.
Categories: FLOSS Project Planets

PyPy: A Knownbits Abstract Domain for the Toy Optimizer, Correctly

Planet Python - Sat, 2024-08-03 10:00

After Max' introduction to abstract interpretation for the toy optimizer in the last post, I want to present a more complicated abstract domain in this post. This abstract domain reasons about the individual bits of a variable in a trace. Every bit can be either "known zero", "known one" or "unknown". The abstract domain is useful for optimizing integer operations, particularly the bitwise operations. The abstract domain follows quite closely the tristate abstract domain of the eBPF verifier in the Linux Kernel, as described by the paper Sound, Precise, and Fast Abstract Interpretation with Tristate Numbers by Harishankar Vishwanathan, Matan Shachnai, Srinivas Narayana, and Santosh Nagarakatte.

The presentation in this post will still be in the context of the toy optimizer. We'll spend a significant part of the post convincing ourselves that the abstract domain transfer functions that we're writing are really correct, using both property-based testing and automated proofs (again using Z3).

PyPy has implemented and merged a more complicated version of the same abstract domain for the "real" PyPy JIT. A more thorough explanation of that real world implementation will follow.

I'd like to thank Max Bernstein and Armin Rigo for lots of great feedback on drafts of this post. The PyPy implementation was mainly done by Nico Rittinghaus and me.

Contents:

Motivation

In many programs that do bit-manipulation of integers, some of the bits of the integer variables of the program can be statically known. Here's a simple example:

x = a | 1 ... if x & 1: ... else: ...

After the assignment x = a | 1, we know that the lowest bit of x must be 1 (the other bits are unknown) and an optimizer could remove the condition x & 1 by constant-folding it to 1.

Another (more complicated) example is:

assert i & 0b111 == 0 # check that i is a multiple of 8 j = i + 16 assert j & 0b111 == 0

This kind of code could e.g. happen in a CPU emulator, where i and j are integers that represent emulated pointers, and the asserts are alignment checks. The first assert implies that the lowest three bits of i must be 0. Adding 16 to such a number produces a result where the lowest three bits are again all 0, therefore the second assert is always true. So we would like a compiler to remove the second assert.

Both of these will optimizations are doable with the help of the knownbits abstract domain that we'll discuss in the rest of the post.

The Knownbits Abstract Domain

An abstract value of the knownbits domain needs to be able to store, for every bit of an integer variable in a program, whether it is known 0, known 1, or unknown. To represent three different states, we need 2 bits, which we will call one and unknown. Here's the encoding:

one unknown knownbit 0 0 0 1 0 1 0 1 ? 1 1 illegal

The unknown bit is set if we don't know the value of the bit ("?"), the one bit is set if the bit is known to be a 1. Since two bits are enough to encode four different states, but we only need three, the combination of a set one bit and a set unknown is not allowed.

We don't just want to encode a single bit, however. Instead, we want to do this for all the bits of an integer variable. Therefore the instances of the abstract domain get two integer fields ones and unknowns, where each pair of corresponding bits encodes the knowledge about the corresponding bit of the integer variable in the program.

We can start implementing a Python class that works like this:

from dataclasses import dataclass @dataclass(eq=False) class KnownBits: ones : int unknowns : int def __post_init__(self): if isinstance(self.ones, int): assert self.is_well_formed() def is_well_formed(self): # a bit cannot be both 1 and unknown return self.ones & self.unknowns == 0 @staticmethod def from_constant(const : int): """ Construct a KnownBits corresponding to a constant, where all bits are known.""" return KnownBits(const, 0) def is_constant(self): """ Check if the KnownBits instance represents a constant. """ # it's a constant if there are no unknowns return self.unknowns == 0

We can also add some convenience properties. Sometimes it is easier to work with an integer where all the known bits are set, or one where the positions of all the known zeros have a set bit:

class KnownBits: ... @property def knowns(self): """ return an integer where the known bits are set. """ # the knowns are just the unknowns, inverted return ~self.unknowns @property def zeros(self): """ return an integer where the places that are known zeros have a bit set. """ # it's a 0 if it is known, but not 1 return self.knowns & ~self.ones

Also, for debugging and for writing tests we want a way to print the known bits in a human-readable form, and also to have a way to construct a KnownBits instance from a string. It's not important to understand the details of __str__ or from_str for the rest of the post, so I'm putting them into a fold:

KnownBits from and to string conversions class KnownBits: ... def __repr__(self): if self.is_constant(): return f"KnownBits.from_constant({self.ones})" return f"KnownBits({self.ones}, {self.unknowns})" def __str__(self): res = [] ones, unknowns = self.ones, self.unknowns # construct the string representation right to left while 1: if not ones and not unknowns: break # we leave off the leading known 0s if ones == -1 and not unknowns: # -1 has all bits set in two's complement, so the leading # bits are all 1 res.append('1') res.append("...") break if unknowns == -1: # -1 has all bits set in two's complement, so the leading bits # are all ? assert not ones res.append("?") res.append("...") break if unknowns & 1: res.append('?') elif ones & 1: res.append('1') else: res.append('0') ones >>= 1 unknowns >>= 1 if not res: res.append('0') res.reverse() return "".join(res) @staticmethod def from_str(s): """ Construct a KnownBits instance that from a string. String can start with ...1 to mean that all higher bits are 1, or ...? to mean that all higher bits are unknown. Otherwise it is assumed that the higher bits are all 0. """ ones, unknowns = 0, 0 startindex = 0 if s.startswith("...?"): unknowns = -1 startindex = 4 elif s.startswith("...1"): ones = -1 startindex = 4 for index in range(startindex, len(s)): ones <<= 1 unknowns <<= 1 c = s[index] if c == '1': ones |= 1 elif c == '?': unknowns |= 1 return KnownBits(ones, unknowns) @staticmethod def all_unknown(): """ convenience constructor for the "all bits unknown" abstract value """ return KnownBits.from_str("...?")

And here's a pytest-style unit test for str:

def test_str(): assert str(KnownBits.from_constant(0)) == '0' assert str(KnownBits.from_constant(5)) == '101' assert str(KnownBits(5, 0b10)) == '1?1' assert str(KnownBits(~0b1111, 0b10)) == '...100?0' assert str(KnownBits(1, ~0b1)) == '...?1'

An instance of KnownBits represents a set of integers, namely those that match the known bits stored in the instance. We can write a method contains that takes a concrete int value and returns True if the value matches the pattern of the known bits:

class KnownBits: ... def contains(self, value : int): """ Check whether the KnownBits instance contains the concrete integer `value`. """ # check whether value matches the bit pattern. in the places where we # know the bits, the value must agree with ones. return value & self.knowns == self.ones

and a test:

def test_contains(): k1 = KnownBits.from_str('1?1') assert k1.contains(0b111) assert k1.contains(0b101) assert not k1.contains(0b110) assert not k1.contains(0b011) k2 = KnownBits.from_str('...?1') # all odd numbers for i in range(-101, 100): assert k2.contains(i) == (i & 1) Transfer Functions

Now that we have implemented the basics of the KnownBits class, we need to start implementing the transfer functions. They are for computing what we know about the results of an operation, given the knownledge we have about the bits of the arguments.

We'll start with a simple unary operation, invert(x) (which is ~x in Python and C syntax), which flips all the bits of at integer. If we know some bits of the arguments, we can compute the corresponding bits of the result. The unknown bits remain unknown.

Here's the code:

class KnownBits: ... def abstract_invert(self): # self.zeros has bits set where the known 0s are in self return KnownBits(self.zeros, self.unknowns)

And a unit-test:

def test_invert(): k1 = KnownBits.from_str('01?01?01?') k2 = k1.abstract_invert() assert str(k2) == '...10?10?10?' k1 = KnownBits.from_str('...?') k2 = k1.abstract_invert() assert str(k2) == '...?'

Before we continue with further transfer functions, we'll think about correctness of the transfer functions and build up some test infrastructure. To test transfer functions, it's quite important to move being simple example-style unit tests. The state-space for more complicated binary transfer functions is extremely large and it's too easy to do something wrong in a corner case. Therefore we'll look at property-based-test for KnownBits next.

Property-based Tests with Hypothesis

We want to do property-based tests of KnownBits, to try make it less likely that we'll get a corner-case in the implementation wrong. We'll use Hypothesis for that.

I can't give a decent introduction to Hypothesis here, but want to give a few hints about the API. Hypothesis is a way to run unit tests with randomly generated input. It provides strategies to describe the data that the test functions expects. Hypothesis provides primitive strategies (for things like integers, strings, floats, etc) and ways to build composite strategies out of the primitive ones.

To be able to write the tests, we need to generate random KnownBits instances, and we also want an int instance that is a member of the KnownBits instance. We generate tuples of (KnownBits, int) together, to ensure this property. We'll ask Hypothesis to generate us a random concrete int as the concrete value, and then we'll also generate a second random int to use as the unknown masks (i.e. which bits of the concrete int we don't know in the KnownBits instance). Here's a function that takes two such ints and builds the tuple:

def build_knownbits_and_contained_number(concrete_value : int, unknowns : int): # to construct a valid KnownBits instance, we need to mask off the unknown # bits ones = concrete_value & ~unknowns return KnownBits(ones, unknowns), concrete_value

We can turn this function into a hypothesis strategy to generate input data using the strategies.builds function:

from hypothesis import strategies, given, settings ints = strategies.integers() random_knownbits_and_contained_number = strategies.builds( build_knownbits_and_contained_number, ints, ints )

One important special case of KnownBits are the constants, which contain only a single concrete value. We'll also generate some of those specifically, and then combine the random_knownbits_and_contained_number strategy with it:

constant_knownbits = strategies.builds( lambda value: (KnownBits.from_constant(value), value), ints ) knownbits_and_contained_number = constant_knownbits | random_knownbits_and_contained_number

Now we can write the first property-based tests, for the KnownBits.contains method:

@given(knownbits_and_contained_number) def test_contains(t): k, n = t assert k.contains(t)

The @given decorator is used to tell Hypothesis which strategy to use to generate random data for the test function. Hypothesis will run the test with a number of random examples (100 by default). If it finds an error, it will try to minimize the example needed that demonstrates the problem, to try to make it easier to understand what is going wrong. It also saves all failing cases into an example database and tries them again on subsequent runs.

This test is as much a check for whether we got the strategies right as it is for the logic in KnownBits.contains. Here's an example output of random concrete and abstract values that we are getting here:

110000011001101 ...?0???1 ...1011011 ...1011011 ...1001101110101000010010011111011 ...1001101110101000010010011111011 ...1001101110101000010010011111011 ...100110111010100001?010?1??1??11 1000001101111101001011010011111101000011000111011001011111101 1000001101111101001011010011111101000011000111011001011111101 1000001101111101001011010011111101000011000111011001011111101 1000001101111101001011010011111101000011000111????01?11?????1 1111100000010 1111100000010 1111100000010 ...?11111?00000?? 110110 110110 110110 ...?00?00????11??10 110110 ??0??0 ...100010111011111 ...?100?10111??111? ...1000100000110001 ...?000?00000??000? 110000001110 ...?0?0??000?00?0?0000000?00???0000?????00???000?0?00?01?000?0??1?? 110000001110 ??000000???0 1011011010000001110101001111000010001001011101010010010001000000010101010010001101110101111111010101010010101100110000011110000 1011011010000001110101001111000010001001011101010010010001000000010101010010001101110101111111010101010010101100110000011110000 ...1011010010010100 ...1011010010010100 ...1011111110110011 ...1011111110110011 101000011110110 101000011?10?1? 100101 ?00?0?

That looks suitably random, but we might want to bias our random numbers a little bit towards common error values like small constants, powers of two, etc. Like this:

INTEGER_WIDTH = 64 # some small integers ints_special = set(range(100)) # powers of two ints_special = ints_special.union(1 << i for i in range(INTEGER_WIDTH - 2)) # powers of two - 1 ints_special = ints_special.union((1 << i) - 1 for i in range(INTEGER_WIDTH - 2)) # negative versions of what we have so far ints_special = ints_special.union(-x for x in ints_special) # bit-flipped versions of what we have so far ints_special = ints_special.union(~x for x in ints_special) ints_special = list(ints_special) # sort them (because hypothesis simplifies towards earlier elements in the list) ints_special.sort(key=lambda element: (abs(element), element < 0)) ints = strategies.sampled_from(ints_special) | strategies.integers()

Now we get data like this:

1110 1110 ...10000000000000000001 ...10000??0??0000??00?1 1 ??0??0000??00?1 1 ? ...10101100 ...10101100 110000000011001010111011111111111111011110010001001100110001011 ...?0?101? 110000000011001010111011111111111111011110010001001100110001011 ??00000000??00?0?0???0??????????????0????00?000?00??00??000?0?? ...1011111111111111111111111111 ...?11?11?? ...1011111111111111111111111111 ...?0?????????????????????????? 0 ...?0?????????????????????????? 101101 101101 111111111111111111111111111111111111111111111 111111111111111111111111111111111111111111111 10111 10111 ...101100 ...1?111011?0 101000 ?001010?0 101000 ?0?000 110010 110010 ...100111 ...100111 1111011010010 1111011010010 ...1000000000000000000000000000000000000 ...1000000000000000000000000000000000000

We can also write a test that checks that the somewhat tricky logic in __str__ and from_str is correct, by making sure that the two functions round-trip (ie converting a KnownBits to a string and then back to a KnownBits instance produces the same abstract value).

@given(knownbits_and_contained_number) def test_hypothesis_str_roundtrips(t1): k1, n1 = t1 s = str(k1) k2 = KnownBits.from_str(s) assert k1.ones == k2.ones assert k1.unknowns == k2.unknowns

Now let's actually apply this infrastructure to test abstract_invert.

When are Transfer Functions Correct? How do we test them?

Abstract values, i.e. instances of KnownBits represent sets of concrete values. We want the transfer functions to compute overapproximations of the concrete values. So if we have an arbitrary abstract value k, with a concrete number n that is a member of the abstract values (i.e. k.contains(n) == True) then the result of the concrete operation op(n) must be a member of the result of the abstract operation k.abstract_op() (i.e. k.abstract_op().contains(op(n)) == True).

Checking the correctness/overapproximation property is a good match for hypothesis. Here's what the test for abstract_invert looks like:

@given(knownbits_and_contained_number) def test_hypothesis_invert(t): k1, n1 = t1 n2 = ~n1 # compute the real result k2 = k1.abstract_invert() # compute the abstract result assert k2.contains(n2) # the abstract result must contain the real result

This is the only condition needed for abstract_invert to be correct. If abstract_invert fulfils this property for every combination of abstract and concrete value then abstract_invert is correct. Note however, that this test does not actually check whether abstract_invert gives us precise results. A correct (but imprecise) implementation of abstract_invert would simply return a completely unknown result, regardless of what is known about the input KnownBits.

The "proper" CS term for this notion of correctness is called soundness. The correctness condition on the transfer functions is called a Galois connection. I won't go into any mathematical/technical details here, but wanted to at least mention the terms. I found Martin Kellogg's slides to be quite an approachable introduction to the Galois connection and how to show soundness.

Implementing Binary Transfer Functions

Now we have infrastructure in place for testing transfer functions with random inputs. With that we can start thinking about the more complicated case, that of binary operations. Let's start with the simpler ones, and and or. For and, we can know a 0 bit in the result if either of the input bits are known 0; or we can know a 1 bit in the result if both input bits are known 1. Otherwise the resulting bit is unknown. Let's look at all the combinations:

and input1: 000111??? input2: 01?01?01? result: 00001?0?? class KnownBits: ... def abstract_and(self, other): ones = self.ones & other.ones # known ones knowns = self.zeros | other.zeros | ones return KnownBits(ones, ~knowns)

Here's an example unit-test and a property-based test for and:

def test_and(): # test all combinations of 0, 1, ? in one example k1 = KnownBits.from_str('01?01?01?') k2 = KnownBits.from_str('000111???') res = k1.abstract_and(k2) # should be: 0...00001?0?? assert str(res) == "1?0??" @given(knownbits_and_contained_number, knownbits_and_contained_number) def test_hypothesis_and(t1, t2): k1, n1 = t1 k2, n2 = t2 k3 = k1.abstract_and(k2) n3 = n1 & n2 assert k3.contains(n3)

To implement or is pretty similar. The result is known 1 where either of the inputs is 1. The result is known 0 where both inputs are known 0, and ? otherwise.

or input1: 000111??? input2: 01?01?01? result: 01?111?1? class KnownBits: ... def abstract_or(self, other): ones = self.ones | other.ones zeros = self.zeros & other.zeros knowns = ones | zeros return KnownBits(ones, ~knowns)

Here's an example unit-test and a property-based test for or:

def test_or(): k1 = KnownBits.from_str('01?01?01?') k2 = KnownBits.from_str('000111???') res = k1.abstract_or(k2) # should be: 0...01?111?1? assert str(res) == "1?111?1?" @given(knownbits_and_contained_number, knownbits_and_contained_number) def test_hypothesis_or(t1, t2): k1, n1 = t1 k2, n2 = t2 k3 = k1.abstract_or(k2) n3 = n1 | n2 assert k3.contains(n3)

Implementing support for abstract_xor is relatively simple, and left as an exercise :-).

Addition and Subtraction

invert, and, and or are relatively simple transfer functions to write, because they compose over the individual bits of the integers. The arithmetic functions add and sub are significantly harder, because of carries and borrows. Coming up with the formulas for them and gaining an intuitive understanding is quite tricky and involves carefully going through a few examples with pen and paper. When implementing this in PyPy, Nico and I didn't come up with the implementation ourselves, but instead took them from the Tristate Numbers paper. Here's the code, with example tests and hypothesis tests:

class KnownBits: ... def abstract_add(self, other): sum_ones = self.ones + other.ones sum_unknowns = self.unknowns + other.unknowns all_carries = sum_ones + sum_unknowns ones_carries = all_carries ^ sum_ones unknowns = self.unknowns | other.unknowns | ones_carries ones = sum_ones & ~unknowns return KnownBits(ones, unknowns) def abstract_sub(self, other): diff_ones = self.ones - other.ones val_borrows = (diff_ones + self.unknowns) ^ (diff_ones - other.unknowns) unknowns = self.unknowns | other.unknowns | val_borrows ones = diff_ones & ~unknowns return KnownBits(ones, unknowns) def test_add(): k1 = KnownBits.from_str('0?10?10?10') k2 = KnownBits.from_str('0???111000') res = k1.abstract_add(k2) assert str(res) == "?????01?10" def test_sub(): k1 = KnownBits.from_str('0?10?10?10') k2 = KnownBits.from_str('0???111000') res = k1.abstract_sub(k2) assert str(res) == "...?11?10" k1 = KnownBits.from_str( '...1?10?10?10') k2 = KnownBits.from_str('...10000???111000') res = k1.abstract_sub(k2) assert str(res) == "111?????11?10" @given(knownbits_and_contained_number, knownbits_and_contained_number) def test_hypothesis_add(t1, t2): k1, n1 = t1 k2, n2 = t2 k3 = k1.abstract_add(k2) n3 = n1 + n2 assert k3.contains(n3) @given(knownbits_and_contained_number, knownbits_and_contained_number) def test_hypothesis_sub(t1, t2): k1, n1 = t1 k2, n2 = t2 k3 = k1.abstract_sub(k2) n3 = n1 - n2 assert k3.contains(n3)

Now we are in a pretty good situation, and have implemented abstract versions for a bunch of important arithmetic and binary functions. What's also surprising is that the implementation of all of the transfer functions is quite efficient. We didn't have to write loops over the individual bits at all, instead we found closed form expressions using primitive operations on the underlying integers ones and unknowns. This means that computing the results of abstract operations is quite efficient, which is important when using the abstract domain in the context of a JIT compiler.

Proving correctness of the transfer functions with Z3

As one can probably tell from my recent posts, I've been thinking about compiler correctness a lot. Getting the transfer functions absolutely correct is really crucial, because a bug in them would lead to miscompilation of Python code when the abstract domain is added to the JIT. While the randomized tests are great, it's still entirely possible for them to miss bugs. The state space for the arguments of a binary transfer function is 3**64 * 3**64, and if only a small part of that contains wrong behaviour it would be really unlikely for us to find it with random tests by chance. Therefore I was reluctant to merge the PyPy branch that contained the new abstract domain for a long time.

To increase our confidence in the correctness of the transfer functions further, we can use Z3 to prove their correctness, which gives us much stronger guarantees (not 100%, obviously). In this subsection I will show how to do that.

Here's an attempt to do this manually in the Python repl:

>>>> import z3 >>>> solver = z3.Solver() >>>> # like last blog post, proof by failing to find counterexamples >>>> def prove(cond): assert solver.check(z3.Not(cond)) == z3.unsat >>>> >>>> # let's set up a z3 bitvector variable for an abitrary concrete value >>>> n1 = z3.BitVec('concrete_value', 64) >>>> n1 concrete_value >>>> # due to operator overloading we can manipulate z3 formulas >>>> n2 = ~n1 >>>> n2 ~concrete_value >>>> >>>> # now z3 bitvector variables for the ones and zeros fields >>>> ones = z3.BitVec('abstract_ones', 64) >>>> unknowns = z3.BitVec('abstract_unknowns', 64) >>>> # we construct a KnownBits instance with the z3 variables >>>> k1 = KnownBits(ones, unknowns) >>>> # due to operator overloading we can call the methods on k1: >>>> k2 = k1.abstract_invert() >>>> k2.ones ~abstract_unknowns & ~abstract_ones >>>> k2.unknowns abstract_unknowns >>>> # here's the correctness condition that we want to prove: >>>> k2.contains(n2) ~concrete_value & ~abstract_unknowns == ~abstract_unknowns & ~abstract_ones >>>> # let's try >>>> prove(k2.contains(n2)) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "<stdin>", line 1, in prove AssertionError >>>> # it doesn't work! let's look at the counterexample to see why: >>>> solver.model() [abstract_unknowns = 0, abstract_ones = 0, concrete_value = 1] >>>> # we can build a KnownBits instance with the values in the >>>> # counterexample: >>>> ~1 # concrete result -2 >>>> counter_example_k1 = KnownBits(0, 0) >>>> counter_example_k1 KnownBits.from_constant(0) >>>> counter_example_k2 = counter_example_k1.abstract_invert() >>>> counter_example_k2 KnownBits.from_constant(-1) >>>> # let's check the failing condition >>>> counter_example_k2.contains(~1) False

What is the problem here? We didn't tell Z3 that n1 was supposed to be a member of k1. We can add this as a precondition to the solver, and then the prove works:

>>>> solver.add(k1.contains(n1)) >>>> prove(k2.contains(n2)) # works!

This is super cool! It's really a proof about the actual implementation, because we call the implementation methods directly, and due to the operator overloading that Z3 does we can be sure that we are actually checking a formula that corresponds to the Python code. This eliminates one source of errors in formal methods.

Doing the proof manually on the Python REPL is kind of annoying though, and we also would like to make sure that the proofs are re-done when we change the code. What we would really like to do is writing the proofs as a unit-test that we can run while developing and in CI. Doing this is possible, and the unit tests that really perform proofs look pleasingly similar to the Hypothesis-based ones.

First we need to set up a bit of infrastructure:

INTEGER_WIDTH = 64 def BitVec(name): return z3.BitVec(name, INTEGER_WIDTH) def BitVecVal(val): return z3.BitVecVal(val, INTEGER_WIDTH) def z3_setup_variables(): # instantiate a solver solver = z3.Solver() # a Z3 variable for the first concrete value n1 = BitVec("n1") # a KnownBits instances that uses Z3 variables as its ones and unknowns, # representing the first abstract value k1 = KnownBits(BitVec("n1_ones"), BitVec("n1_unkowns")) # add the precondition to the solver that the concrete value n1 must be a # member of the abstract value k1 solver.add(k1.contains(n1)) # a Z3 variable for the second concrete value n2 = BitVec("n2") # a KnownBits instances for the second abstract value k2 = KnownBits(BitVec("n2_ones"), BitVec("n2_unkowns")) # add the precondition linking n2 and k2 to the solver solver.add(k2.contains(n2)) return solver, k1, n1, k2, n2 def prove(cond, solver): z3res = solver.check(z3.Not(cond)) if z3res != z3.unsat: assert z3res == z3.sat # can't be timeout, we set no timeout # make the model with the counterexample global, to make inspecting the # bug easier when running pytest --pdb global model model = solver.model() print(f"n1={model.eval(n1)}, n2={model.eval(n2)}") counter_example_k1 = KnownBits(model.eval(k1.ones).as_signed_long(), model.eval(k1.unknowns).as_signed_long()) counter_example_k2 = KnownBits(model.eval(k2.ones).as_signed_long(), model.eval(k2.unknowns).as_signed_long()) print(f"k1={counter_example_k1}, k2={counter_example_k2}") print(f"but {cond=} evaluates to {model.eval(cond)}") raise ValueError(solver.model())

And then we can write proof-unit-tests like this:

def test_z3_abstract_invert(): solver, k1, n1, _, _ = z3_setup_variables() k2 = k1.abstract_invert() n2 = ~n1 prove(k2.contains(n2), solver) def test_z3_abstract_and(): solver, k1, n1, k2, n2 = z3_setup_variables() k3 = k1.abstract_and(k2) n3 = n1 & n2 prove(k3.contains(n3), solver) def test_z3_abstract_or(): solver, k1, n1, k2, n2 = z3_setup_variables() k3 = k1.abstract_or(k2) n3 = n1 | n2 prove(k3.contains(n3), solver) def test_z3_abstract_add(): solver, k1, n1, k2, n2 = z3_setup_variables() k3 = k1.abstract_add(k2) n3 = n1 + n2 prove(k3.contains(n3), solver) def test_z3_abstract_sub(): solver, k1, n1, k2, n2 = z3_setup_variables() k3 = k1.abstract_sub(k2) n3 = n1 - n2 prove(k3.contains(n3), solver)

It's possible to write a bit more Python-metaprogramming-magic and unify the Hypothesis and Z3 tests into the same test definition.1

Cases where this style of Z3 proof doesn't work

Unfortunately the approach described in the previous section only works for a very small number of cases. It breaks down as soon as the KnownBits methods that we're calling contain any if conditions (including hidden ones like the short-circuiting and and or in Python). Let's look at an example and implement abstract_eq. eq is supposed to be an operation that compares two integers and returns 0 or 1 if they are different or equal, respectively. Implementing this in knownbits looks like this (with example and hypothesis tests):

class KnownBits: ... def abstract_eq(self, other): # the result is a 0, 1, or ? # if they are both the same constant, they must be equal if self.is_constant() and other.is_constant() and self.ones == other.ones: return KnownBits.from_constant(1) # check whether we have known disagreeing bits, then we know the result # is 0 if self._disagrees(other): return KnownBits.from_constant(0) return KnownBits(0, 1) # an unknown boolean def _disagrees(self, other): # check whether the bits disagree in any place where both are known both_known = self.knowns & other.knowns return self.ones & both_known != other.ones & both_known def test_eq(): k1 = KnownBits.from_str('...?') k2 = KnownBits.from_str('...?') assert str(k1.abstract_eq(k2)) == '?' k1 = KnownBits.from_constant(10) assert str(k1.abstract_eq(k1)) == '1' k1 = KnownBits.from_constant(10) k2 = KnownBits.from_constant(20) assert str(k1.abstract_eq(k2)) == '0' @given(knownbits_and_contained_number, knownbits_and_contained_number) def test_hypothesis_eq(t1, t2): k1, n1 = t1 k2, n2 = t2 k3 = k1.abstract_eq(k2) assert k3.contains(int(n1 == n2))

Trying to do the proof in the same style as before breaks:

>>>> k3 = k1.abstract_eq(k2) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "knownbits.py", line 246, in abstract_eq if self._disagrees(other): File "venv/site-packages/z3/z3.py", line 381, in __bool__ raise Z3Exception("Symbolic expressions cannot be cast to concrete Boolean values.") z3.z3types.Z3Exception: Symbolic expressions cannot be cast to concrete Boolean values.

We cannot call abstract_eq on a KnownBits with Z3 variables as fields, because once we hit an if statement, the whole approach of relying on the operator overloading breaks down. Z3 doesn't actually parse the Python code or anything advanced like that, we rather build an expression only by running the code and letting the Z3 formulas build up.

To still prove the correctness of abstract_eq we need to manually transform the control flow logic of the function into a Z3 formula that uses the z3.If expression, using a small helper function:

def z3_cond(b, trueval=1, falseval=0): return z3.If(b, BitVecVal(trueval), BitVecVal(falseval)) def z3_abstract_eq(k1, k2): # follow the *logic* of abstract_eq, we can't call it due to the ifs in it case1cond = z3.And(k1.is_constant(), k2.is_constant(), k1.ones == k2.ones) case2cond = k1._disagrees(k2) # ones is 1 in the first case, 0 otherwise ones = z3_cond(case1cond, 1, 0) # in the first two cases, unknowns is 0, 1 otherwise unknowns = z3_cond(z3.Or(case1cond, case2cond), 0, 1) return KnownBits(ones, unknowns) def test_z3_abstract_eq_logic(): solver, k1, n1, k2, n2 = z3_setup_variables() n3 = z3_cond(n1 == n2) # concrete result k3 = z3_abstract_eq(k1, k2) prove(k3.contains(n3), solver)

This proof works. It is a lot less satisfying than the previous ones though, because we could have done an error in the manual transcription from Python code to Z3 formulas (there are possibly more heavy-handed approaches where we do this transformation more automatically using e.g. the ast module to analyze the source code, but that's a much more complicated researchy project). To lessen this problem somewhat we can factor out the parts of the logic that don't have any conditions into small helper methods (like _disagrees in this example) and use them in the manual conversion of the code to Z3 formulas.2

The final condition that Z3 checks, btw, is this one:

If(n1 == n2, 1, 0) & ~If(Or(And(n1_unkowns == 0, n2_unkowns == 0, n1_ones == n2_ones), n1_ones & ~n1_unkowns & ~n2_unkowns != n2_ones & ~n1_unkowns & ~n2_unkowns), 0, 1) == If(And(n1_unkowns == 0, n2_unkowns == 0, n1_ones == n2_ones), 1, 0) Making Statements about Precision

So far we have only used Z3 to prove statements about correctness, i.e. that our abstract operations overapproximate what can happen with concrete values. While proving this property is essential if we want to avoid miscompilation, correctness alone is not a very strong constraint on the implementation of our abstract transfer functions. We could simply return Knownbits.unknowns() for every abstract_* method and the resulting overapproximation would be correct, but useless in practice.

It's much harder to make statements about whether the transfer functions are maximally precise. There are two aspects of precision I want to discuss in this section, however.

The first aspect is that we would really like it if the transfer functions compute the maximally precise results for singleton sets. If all abstract arguments of an operations are constants, i.e. contain only a single concrete element, then we know that the resulting set also has only a single element. We can prove that all our transfer functions have this property:

def test_z3_prove_constant_folding(): solver, k1, n1, k2, n2 = z3_setup_variables() k3 = k1.abstract_invert() prove(z3.Implies(k1.is_constant(), k3.is_constant()), solver) k3 = k1.abstract_and(k2) prove(z3.Implies(z3.And(k1.is_constant(), k2.is_constant()), k3.is_constant()), solver) k3 = k1.abstract_or(k2) prove(z3.Implies(z3.And(k1.is_constant(), k2.is_constant()), k3.is_constant()), solver) k3 = k1.abstract_sub(k2) prove(z3.Implies(z3.And(k1.is_constant(), k2.is_constant()), k3.is_constant()), solver) k3 = z3_abstract_eq(k1, k2) prove(z3.Implies(z3.And(k1.is_constant(), k2.is_constant()), k3.is_constant()), solver)

Proving with Z3 that the transfer functions are maximally precise for non-constant arguments seems to be relatively hard. I tried a few completely rigorous approaches and failed. The paper Sound, Precise, and Fast Abstract Interpretation with Tristate Numbers contains an optimality proof for the transfer functions of addition and subtraction, so we can be certain that they are as precise as is possible.

I still want to show an approach for trying to find concrete examples of abstract values that are less precise than they could be, using a combination of Hypothesis and Z3. The idea is to use hypothesis to pick random abstract values. Then we compute the abstract result using our transfer function. Afterwards we can ask Z3 to find us an abstract result that is better than the one our transfer function produced. If Z3 finds a better abstract result, we have a concrete example of imprecision for our transfer function. Those tests aren't strict proofs, because they rely on generating random abstract values, but they can still be valuable (not for the transfer functions in this blog post, which are all optimal).

Here is what the code looks like (this is a little bit bonus content, I'll not explain the details and can only hope that the comments are somewhat helpful):

@given(random_knownbits_and_contained_number, random_knownbits_and_contained_number) @settings(deadline=None) def test_check_precision(t1, t2): k1, n1 = t1 k2, n2 = t2 # apply transfer function k3 = k1.abstract_add(k2) example_res = n1 + n2 # try to find a better version of k3 with Z3 solver = z3.Solver() solver.set("timeout", 8000) var1 = BitVec('v1') var2 = BitVec('v2') ones = BitVec('ones') unknowns = BitVec('unknowns') better_k3 = KnownBits(ones, unknowns) print(k1, k2, k3) # we're trying to find an example for a better k3, so we use check, without # negation: res = solver.check(z3.And( # better_k3 should be a valid knownbits instance better_k3.is_well_formed(), # it should be better than k3, ie there are known bits in better_k3 # that we don't have in k3 better_k3.knowns & ~k3.knowns != 0, # now encode the correctness condition for better_k3 with a ForAll: # for all concrete values var1 and var2, it must hold that if # var1 is in k1 and var2 is in k2 it follows that var1 + var2 is in # better_k3 z3.ForAll( [var1, var2], z3.Implies( z3.And(k1.contains(var1), k2.contains(var2)), better_k3.contains(var1 + var2))))) # if this query is satisfiable, we have found a better result for the # abstract_add if res == z3.sat: model = solver.model() rk3 = KnownBits(model.eval(ones).as_signed_long(), model.eval(unknowns).as_signed_long()) print("better", rk3) assert 0 if res == z3.unknown: print("timeout")

It does not actually fail for abstract_add (nor the other abstract functions). To see the test failing we can add some imprecision to the implementation of abstract_add to see Hypothesis and Z3 find examples of values that are not optimally precise (for example by setting some bits of unknowns in the implementation of abstract_add unconditionally).

Using the Abstract Domain in the Toy Optimizer for Generalized Constant Folding

Now after all this work we can finally actually use the knownbits abstract domain in the toy optimizer. The code for this follows Max' intro post about abstract interpretation quite closely.

For completeness sake, in the fold there's the basic infrastructure classes that make up the IR again (they are identical or at least extremely close to the previous toy posts).

toy infrastructure class Value: def find(self): raise NotImplementedError("abstract") @dataclass(eq=False) class Operation(Value): name : str args : list[Value] forwarded : Optional[Value] = None def find(self) -> Value: op = self while isinstance(op, Operation): next = op.forwarded if next is None: return op op = next return op def arg(self, index): return self.args[index].find() def make_equal_to(self, value : Value): self.find().forwarded = value @dataclass(eq=False) class Constant(Value): value : object def find(self): return self class Block(list): def __getattr__(self, opname): def wraparg(arg): if not isinstance(arg, Value): arg = Constant(arg) return arg def make_op(*args): op = Operation(opname, [wraparg(arg) for arg in args]) self.append(op) return op return make_op def bb_to_str(l : Block, varprefix : str = "var"): def arg_to_str(arg : Value): if isinstance(arg, Constant): return str(arg.value) else: return varnames[arg] varnames = {} res = [] for index, op in enumerate(l): # give the operation a name used while # printing: var = f"{varprefix}{index}" varnames[op] = var arguments = ", ".join( arg_to_str(op.arg(i)) for i in range(len(op.args)) ) strop = f"{var} = {op.name}({arguments})" res.append(strop) return "\n".join(res)

Now we can write some first tests, the first one simply checking constant folding:

def test_constfold_two_ops(): bb = Block() var0 = bb.getarg(0) var1 = bb.int_add(5, 4) var2 = bb.int_add(var1, 10) var3 = bb.int_add(var2, var0) opt_bb = simplify(bb) assert bb_to_str(opt_bb, "optvar") == """\ optvar0 = getarg(0) optvar1 = int_add(19, optvar0)"""

Calling the transfer functions on constant KnownBits produces a constant results, as we have seen. Therefore "regular" constant folding should hopefully be achieved by optimizing with the KnownBits abstract domain too.

The next two tests are slightly more complicated and can't be optimized by regular constant-folding. They follow the motivating examples from the start of this blog post, a hundred years ago:

def test_constfold_via_knownbits(): bb = Block() var0 = bb.getarg(0) var1 = bb.int_or(var0, 1) var2 = bb.int_and(var1, 1) var3 = bb.dummy(var2) opt_bb = simplify(bb) assert bb_to_str(opt_bb, "optvar") == """\ optvar0 = getarg(0) optvar1 = int_or(optvar0, 1) optvar2 = dummy(1)""" def test_constfold_alignment_check(): bb = Block() var0 = bb.getarg(0) var1 = bb.int_invert(0b111) # mask off the lowest three bits, thus var2 is aligned var2 = bb.int_and(var0, var1) # add 16 to aligned quantity var3 = bb.int_add(var2, 16) # check alignment of result var4 = bb.int_and(var3, 0b111) var5 = bb.int_eq(var4, 0) # var5 should be const-folded to 1 var6 = bb.dummy(var5) opt_bb = simplify(bb) assert bb_to_str(opt_bb, "optvar") == """\ optvar0 = getarg(0) optvar1 = int_and(optvar0, -8) optvar2 = int_add(optvar1, 16) optvar3 = dummy(1)"""

Here is simplify to make these tests pass:

def unknown_transfer_functions(*abstract_args): return KnownBits.all_unknown() def simplify(bb: Block) -> Block: abstract_values = {} # dict mapping Operation to KnownBits def knownbits_of(val : Value): if isinstance(val, Constant): return KnownBits.from_constant(val.value) return abstract_values[val] opt_bb = Block() for op in bb: # apply the transfer function on the abstract arguments name_without_prefix = op.name.removeprefix("int_") method_name = f"abstract_{name_without_prefix}" transfer_function = getattr(KnownBits, method_name, unknown_transfer_functions) abstract_args = [knownbits_of(arg.find()) for arg in op.args] abstract_res = abstract_values[op] = transfer_function(*abstract_args) # if the result is a constant, we optimize the operation away and make # it equal to the constant result if abstract_res.is_constant(): op.make_equal_to(Constant(abstract_res.ones)) continue # otherwise emit the op opt_bb.append(op) return opt_bb

The code follows the approach from the previous blog post very closely. The only difference is that we apply the transfer function first, to be able to detect whether the abstract domain can tell us that the result has to always be a constant. This code makes all three tests pass.

Using the KnownBits Domain for Conditional Peephole Rewrites

So far we are only using the KnownBits domain to find out that certain operations have to produce a constant. We can also use the KnownBits domain to check whether certain operation rewrites are correct. Let's use one of the examples from the Mining JIT traces for missing optimizations with Z3 post, where Z3 found the inefficiency (x << 4) & -0xf == x << 4 in PyPy JIT traces. We don't have shift operations, but we want to generalize this optimization anyway. The general form of this rewrite is that under some circumstances x & y == x, and we can use the KnownBits domain to detect situations where this must be true.

To understand when x & y == x is true, we can think about individual pairs of bits a and b. If a == 0, then a & b == 0 & b == 0 == a. If b == 1 then a & b == a & 1 == a. So if either a == 0 or b == 1 is true, a & b == a follows. And if either of these conditions is true for all the bits of x and y, we can know that x & y == x.

We can write a method on KnownBits to check for this condition:

class KnownBits: ... def is_and_identity(self, other): """ Return True if n1 & n2 == n1 for any n1 in self and n2 in other. (or, equivalently, return True if n1 | n2 == n2)""" return self.zeros | other.ones == -1

Since my reasoning about this feels ripe for errors, let's check that our understanding is correct with Z3:

def test_prove_is_and_identity(): solver, k1, n1, k2, n2 = z3_setup_variables() prove(z3.Implies(k1.is_and_identity(k2), n1 & n2 == n1), solver)

Now let's use this in the toy optimizer. Here are two tests for this rewrite:

def test_remove_redundant_and(): bb = Block() var0 = bb.getarg(0) var1 = bb.int_invert(0b1111) # mask off the lowest four bits var2 = bb.int_and(var0, var1) # applying the same mask is not redundant var3 = bb.int_and(var2, var1) var4 = bb.dummy(var3) opt_bb = simplify(bb) assert bb_to_str(opt_bb, "optvar") == """\ optvar0 = getarg(0) optvar1 = int_and(optvar0, -16) optvar2 = dummy(optvar1)""" def test_remove_redundant_and_more_complex(): bb = Block() var0 = bb.getarg(0) var1 = bb.getarg(1) # var2 has bit pattern ???? var2 = bb.int_and(var0, 0b1111) # var3 has bit pattern ...?1111 var3 = bb.int_or(var1, 0b1111) # var4 is just var2 var4 = bb.int_and(var2, var3) var5 = bb.dummy(var4) opt_bb = simplify(bb) assert bb_to_str(opt_bb, "optvar") == """\ optvar0 = getarg(0) optvar1 = getarg(1) optvar2 = int_and(optvar0, 15) optvar3 = int_or(optvar1, 15) optvar4 = dummy(optvar2)"""

The first test could also be made to pass by implementing a reassociation optimization that turns (x & c1) & c2 into x & (c1 & c2) and then constant-folds the second and. But here we want to use KnownBits and conditionally rewrite int_and to its first argument. So to make the tests pass, we can change simplify like this:

def simplify(bb: Block) -> Block: abstract_values = {} # dict mapping Operation to KnownBits def knownbits_of(val : Value): ... opt_bb = Block() for op in bb: # apply the transfer function on the abstract arguments name_without_prefix = op.name.removeprefix("int_") method_name = f"abstract_{name_without_prefix}" transfer_function = getattr(KnownBits, method_name, unknown_transfer_functions) abstract_args = [knownbits_of(arg.find()) for arg in op.args] abstract_res = abstract_values[op] = transfer_function(*abstract_args) # if the result is a constant, we optimize the operation away and make # it equal to the constant result if abstract_res.is_constant(): op.make_equal_to(Constant(abstract_res.ones)) continue # <<<< new code # conditionally rewrite int_and(x, y) to x if op.name == "int_and": k1, k2 = abstract_args if k1.is_and_identity(k2): op.make_equal_to(op.arg(0)) continue # >>>> end changes opt_bb.append(op) return opt_bb

And with that, the new tests pass as well. A real implementation would also check the other argument order, but we leave that out for the sake of brevity.

This rewrite also generalizes the rewrites int_and(0, x) -> 0 and int_and(-1, x) -> x, let's add a test for those:

def test_remove_and_simple(): bb = Block() var0 = bb.getarg(0) var1 = bb.getarg(1) var2 = bb.int_and(0, var0) # == 0 var3 = bb.int_invert(var2) # == -1 var4 = bb.int_and(var1, var3) # == var1 var5 = bb.dummy(var4) opt_bb = simplify(bb) assert bb_to_str(opt_bb, "optvar") == """\ optvar0 = getarg(0) optvar1 = getarg(1) optvar2 = dummy(optvar1)"""

This test just passes. And that's it for this post!

Conclusion

In this post we've seen the implementation, testing and proofs about a 'known bits' abstract domain, as well as its use in the toy optimizer to generalize constant folding, and to implement conditional peephole rewrites.

In the next posts I'll write about the real implementation of a knownbits domain in PyPy's JIT, its combination with the existing interval abstract domain, how to deal with gaining informations from conditions in the program, and some lose ends.

Sources:

  1. There's a subtletly about the Z3 proofs that I'm sort of glossing over here. Python integers are of arbitrary width, and the KnownBits code is actually carefully written to work for integers of any size. This property is tested by the Hypothesis tests, which don't limit the sizes of the generated random integers. However, the Z3 proofs only check bitvectors of a fixed bitwidth of 64. There are various ways to deal with this situation. For most "real" compilers, the bitwidth of integers would be fixed anyway. Then the components ones and unknowns of the KnownBits class would use the number of bits the corresponding integer variable has, and the Z3 proofs would use the same width. This is what we do in the PyPy JIT. ↩

  2. The less close connection between implementation and proof for abstract_eq is one of the reasons why it makes sense to do unit-testing in addition to proofs. For a more detailed explanation of why both tests and proofs are good to have, see Jeremy Siek's blog post, as well as the Knuth quote. ↩

Categories: FLOSS Project Planets

This week in KDE: Discover and more

Planet KDE - Sat, 2024-08-03 01:26

It was a big week for Discover, which received multiple UI improvements, performance enhancements, and bug fixes that you’ll find mentioned throughout the text!

There are more features and UI improvements to other components as well, plus a bunch of juicy bug fixes. I’m feeling like we’ve turned the corner on those bugs. No really significant Plasma bugs have been reported in the past week or two, just little ones that are easily squashed. Plasma is really feeling solid these days!

Notable New Features

You can now re-bind the buttons on drawing tablet pens to mouse clicks if you’d like, in addition to the existing feature to bind them to keyboard shortcuts. And the user interface for this is now much better and clearer (Joshua Goins, Plasma 6.2.0. Link):

There’s now an on-by-default sound that plays when you connect or disconnect a screen, to help you figure out whether it was connected successfully — just like we already do for USB devices (Kai Uwe Broulik, Plasma 6.2.0. Link)

Notable UI Improvements

Plasma’s Task Manager textual-list-style group popup now scales properly (Christoph Wolk, Plasma 6.1.4. Link)

Plasma’s Battery Monitor widget once again stays visible while plugged in and charging but not fully charged yet (me: Nate Graham, Plasma 6.2.0. Link)

Landed a minor redesign of Discover’s app page to better conform to the HIG, including the following changes:

  • Better and more consistent margins and padding
  • Better and more compact display of the content rating information
  • Use underlined links rather than buttons for opening web URLs
  • Replace internal separator lines with whitespace
  • Move display of distro-packaged apps’ permissions to the bottom

(me: Nate Graham, Plasma 6.2.0. Link 1, link 2, link 3, link 4):

The menu of clipboard items that appears when you press Meta+V now shares its UI with the Plasma Clipboard widget, offering maintenance benefits, a more consistent UI, and better visualization for long text and images (Fushan Wen, Plasma 6.2.0. Link):

In Welcome Center, the pages introducing Overview and Plasma Vaults now have beautiful, rich graphics depicting the features themselves, and like all the others, they respect your system’s active theme settings, too (Oliver Beard, Plasma 6.2.0. Link 1 and link 2):

The frequency with which Discover’s notifier System Tray icon appears now respects the “Notification frequency” setting that you can choose in System Settings, matching the frequency with which system notifications about updates appear (Thomas Duckworth, Plasma 6.2.0. Link)

When you tile a Breeze-themed window to the left or right screen edge, the window’s top-most pixels no longer allow the window to be resized by dragging, breaking Fitts’ Law for those pixels (Vlad Zahorodnii, Plasma 6.2.0. Link)

Plasma’s Activities widget now scales properly and no longer grows too large with a really thick panel (me: Nate Graham, Plasma 6.2.0. Link 1 and link 2)

System Settings’ Night Light page now prevents you from setting manual timings that cause the start and stop transitions to overlap, and shows this visually, too (Ismael Asensio, Plasma 6.2.0. Link)

Made the menu button on System Settings’ Autostart page conform to the HIG (Christoph Wolk, Plasma 6.2.0. Link)

Made the list-remove Breeze icon look like a red X, same as edit-delete-remove. This helps to standardize on the red X symbolism for “remove this abstract thing” that the HIG recommends (me: Nate Graham, Frameworks 6.5. Link):

Notable Bug Fixes

Fixed a somewhat common way that Powerdevil could crash after the system went to sleep due to inactivity (Jakob Petsovits, Plasma 6.1.4. Link)

When Flatpak/sandboxed/portal-using apps request inhibiting sleep, it now actually works! (Jakob Petsovits, Plasma 6.1.4. Link)

When you move a Plasma panel to another screen edge, its widgets no longer inappropriately become interactive until you leave Edit Mode (Marco Martin, Plasma 6.1.4. Link)

Fixed two issues with Plasma’s “Centered” and “Scaled and cropped” wallpaper positioning modes that caused images of certain sizes to be displayed incorrectly with certain screen scales (Marco Martin, Plasma 6.1.4. Link 1 and link 2)

Fixed three Plasma 6 porting regressions in Folder View that caused the widget representation to lose its custom title feature, caused existing labels to remain visible while renaming, and made it impossible to select other items with the keyboard after renaming something (Marco Martin and me: Nate Graham, Plasma 6.1.4. Link 1, link 2, and link 3)

Discover no longer cuts off the first letter of the name of non-SPDX-compatible licenses when it displays them on the app page (me: Nate Graham, Plasma 6.1.4. Link)

When Alt+Tabbing through windows, tab keystrokes no longer leak into XWayland-using apps when using default XWayland app keyboard snooping setting (David Edmundson, Plasma 6.2.0. Link)

Maximized XWayland-using apps no longer leave pixel gaps on the side of the screen with certain fractional scale factors (Xaver Hugl, Plasma 6.2.0. Link)

Fixed a Qt bug that caused many Plasma crashes while performing a variety of everyday activities with multiple screens are connected (David Edmundson, Qt 6.7.4 and 6.8.0. Link)

Other bug information of note:

Notable in Performance & Technical

Made the icon loading code in Discover non-blocking, which speeds up launch time and improves scrolling smoothness (Harald Sitter, Plasma 6.2.0. Link)

The “Ring system bell when modifier keys are used” and “Ring system bell when locking keys are toggled” Sticky Keys features are now implemented on Wayland. This completes the project to gain full Sticky Keys support! (Nicolas Fella, Plasma 6.2.0. Link 1, link 2, and link 3)

KWin no longer chooses an inappropriate default scale factor for really wacky screens that mis-report their physical dimensions badly enough that they say they’re between zero and three millimeters wide or tall (me: Nate Graham, Plasma 6.2.0. Link)

On Wayland, apps that intentionally suppress cursor launch feedback now have more correct activation behaviors (Nicolas Fella, Frameworks 6.5. Link)

Notable in Automation & Systematization

Added an “All bugs reported by me” link to the homepage on https://bugs.kde.org, so now you can truly see all of your bug reports, not just the open ones (me: Nate Graham, link)

Shortened the messages sent by the bug janitor warning that bugs will be auto-closed soon (Oliver Beard, link)

Adjusted the new bug template to be more accurate about how you fill in version numbers, including recommending using the kinfo command-line tool (me: Nate Graham, link)

…And Everything Else

This blog only covers the tip of the iceberg! If you’re hungry for more, check out https://planet.kde.org, where you can find more news from other KDE contributors.

How You Can Help

If you use have multiple systems or an adventurous personality, you can really help us out by installing beta versions of Plasma using your distro’s available repos and reporting bugs. Arch, Fedora, and openSUSE Tumbleweed are examples of great distros for this purpose. So please please do try out Plasma beta versions. It truly does help us! Heck, if you’re very adventurous, live on the nightly repos. I’ve been doing this full-time for 5 years with my sole computer and it’s surprisingly stable.

Does that sound too scary? Consider donating today instead! That helps too.

Otherwise, visit https://community.kde.org/Get_Involved to discover other ways to be part of a project that really matters. Each contributor makes a huge difference in KDE; you are not a number or a cog in a machine! You don’t have to already be a programmer, either. I wasn’t when I got started. Try it, you’ll like it! We don’t bite!

Categories: FLOSS Project Planets

Paul Wise: FLOSS Activities July 2024

Planet Debian - Fri, 2024-08-02 23:10
Focus

This month I didn't have any particular focus. I just worked on issues in my info bubble.

Issues
  • Unnecessary deps in zlint
Administration
  • Debian IRC: add an entry message redirecting folks from #debian-ci to #debci
Communication
  • Respond to queries from folks on Debian and other IRC channels.
Sponsors

All work was done on a volunteer basis.

Categories: FLOSS Project Planets

Twin Cities Drupal Camp: Early Bird Tickets Are Almost Gone!

Planet Drupal - Fri, 2024-08-02 21:33
Early Bird Tickets Are Almost Gone! Published Date Friday, August 2nd, 2024 - 09:33 pm bcross Fri, 08/02/2024 - 21:33 Twin Cities Drupal Camp 2024 Early Bird Tickets Are Almost Sold Out! 

Now is your last chance to save before regular pricing takes affect. Twin Cities Drupal Camp is coming on September 12-13, 2024, at the University of Minnesota campus in Minneapolis.

Registration includes access to all sessions and events, including the keynote and the unconference. Meals and social events are also part of the deal, free of additional cost. 

This Early Bird rate won’t last forever, so do it now.

Register today! 

Posted In Drupal Planet
Categories: FLOSS Project Planets

Akademy 2023 and 2024

Planet KDE - Fri, 2024-08-02 20:00
Akademy 2023 was almost year ago and soon Akademy 2024 is coming. This is probably good time to talk about Akademy 2023. I know it was in way too past but some of those who know me personally/professionally know that last year has been rollar-coaster for me emotionally and did not manage to write about event while recovering from it. But since this post was sitting in draft from long time, it is finally time to finish and publish it.
Categories: FLOSS Project Planets

Python Morsels: How to make a tuple

Planet Python - Fri, 2024-08-02 17:36

Tuples are technically just immutable lists, but by convention we tend to use tuples and lists for quite different purposes.

Table of contents

  1. Making tuples in Python
  2. Tuples are like lists, but immutable
  3. Tuples are all over the place
  4. The parentheses are optional: it's the commas that make the tuple
  5. When should you make a tuple?
  6. Returning multiple values from a function
  7. Summary

Making tuples in Python

Here's a list named coordinates:

>>> coordinates = [3, 4, 5] >>> type(coordinates) <class 'list'>

It's a list because we used square brackets ([...]) to make it.

If we had used parentheses ((...)) instead, we would've made a tuple:

>>> coordinates = (3, 4, 5) >>> type(coordinates) <class 'tuple'> >>> coordinates (3, 4, 5) Tuples are like lists, but immutable

Like a list, a tuple …

Read the full article: https://www.pythonmorsels.com/how-to-make-a-tuple/
Categories: FLOSS Project Planets

Amarok 3.1 "Tricks of the Light" released!

Planet KDE - Fri, 2024-08-02 17:00

The Amarok Development Squad is happy to announce the immediate availability of Amarok 3.1 "Tricks of the Light"!

Coming three months after 3.0.0 and two months after the first bugfix release 3.0.1, the main development focus in 3.1 has been getting Qt6 / KDE Frameworks 6 based version closer. We are not quite there yet, but not that far away anymore. And there are some quite nice new features too! Amarok 3.1.0 brings in a refreshed Last.fm integration, which uses more up-to-date account connection mechanisms, and is better at informing users of any Last.fm errors. Similar Artists context applet does a comeback, and there's naturally also a nice bunch of smaller features and bug fixes; this time the oldest fulfilled feature request was filed just under 15 years ago.

Changes since 3.0.1 FEATURES:
  • Last.fm plugin updated to use token-based authentication method and to notify user of session key errors (BR 414826, BR 327547)
  • Reintroducing Last.fm Similar Artists context applet - a new Amarok 3 version
  • Remember the previous destination provider when saving playlist (BR 216528)
CHANGES:
  • Amarok now depends on KDE Frameworks 5.89.
  • Cleanup of unused code and various changes that improve Qt6 compatibility but shouldn't affect functionality. (n.b. one won't be able to compile a Qt6 Amarok with 3.1 yet, but perhaps with the eventual 3.2)
  • Remove old derelict openDesktop.org integrations from about dialog. This also removes the dependency to Attica framework.
  • Disable gapless playback if ReplayGain is active and the following track is not from same album, to avoid volume spikes due to delay in the applying of ReplayGain (BR 299461)
BUGFIXES:
  • Small UI and compilation fixes
  • Fix saving and restoring playlist queue on quit / restart (BR 338741)
  • Fix system tray icon menu reordering
  • Fix erroneous apparent zero track progresses on track changes, which caused playcount updates and scrobbles to get skipped (BR 337849, BR 406701)
  • Fix 'save playlist' button in playlist controls
  • Sort playlist sorting breadcrumb menu by localized names (BR 277146)
  • Miscellaneous fixes to saving and loading various playlist file formats, resulting also in improved compatibility with other software (including BR 435779, BR 333745)
  • Don't show false reordering visual hints on a sorted playlist (BR 254821)
  • Fix multiple instances of web services appearing in Internet menu after saving plugin config.
  • Show podcast provider actions for non-empty podcast categories, too (BR 371192)
  • Fix threading-related crashes in CoverManager (BR 490147)

In comparison to changes between 2.9 to 3.0, the git repository statistics between 3.0 and 3.1 are somewhat short:

Tuomas Nurmi: 164 commits, +11910, -29957
l10n daemon script: 97 commits, +207075, -237380
Pino Toscano: 13 commits, +1, -11152

However, this is an excellent spot to send a huge thank you out to everyone who has been on board outside the git history; translators, packagers, bug reporters, writers, commenters, and of course: users - music fans all around the world! Happy listening, everyone! You rok!

Getting Amarok

In addition to source code, Amarok is available for installation from many distributions' package repositories, which are likely to update to 3.1.0 soon. A flatpak is currently available on flathub-beta.

Packager section

You can find the package on download.kde.org and it has been signed with Tuomas Nurmi's GPG key.

Categories: FLOSS Project Planets

Wim Leers: XB week 10: no field widget left behind

Planet Drupal - Fri, 2024-08-02 14:32

The Cypress front-end testing infrastructure clean-up landed on Monday, so this week we’ve already been seeing increased velocity! Last week, we landed the initial implementation of the primary menu, this week it was improved by Harumi “hooroomoo” Jang:

XB’s primary menu now closes after dropping a dragged component onto the canvas. Issue #3458617, image by Harumi.

We saw a huge leap forward this week, thanks to Ben “bnjmnm” Mullins! He’s taking an unchanged PHP-based form definition and is rendering it using React and TSX! :O
Why? To prove we can render existing (core/contrib/custom) Field Widgets, because a goal for XB is to keep existing functionality working. Here’s what that looks like:

A React+TSX-rendered Drupal form to edit the props of the selected component. Incredibly ugly, because no CSS/JS is loaded yet, but mostly because the original Drupal form also is incredibly ugly — you’re seeing part of TwoTerribleTextAreasWidget (written by me to get us started)! Expect significant improvements in the coming weeks.

That screenshot does not do Ben’s monumental work justice. We’re of course already planning to improve that, starting with … no longer using TwoTerribleTextAreasWidget: #3461422: Evolve component instance edit form to become simpler: generate a Field Widget directly. Expect future screenshots and GIFs to be far more convincing :)

This leap also made it became critically important that the Cypress end-to-end tests (tests/src/Cypress/cypress/e2e/xb-general.cy.js) would actually test both the client and server, with the client actually talking to the server. (Until now, xb-general.cy.js was talking to the mock server!) So, Ben also made that happen. (Long overdue ever since the client and server first got connected … 4 weeks ago.)

Back end

On the back-end side, Ben also improved DX and velocity by removing XB’s dependency on the sdc_test module, which was kinda tricky to install (due to it being a test-only module). This simplifies the onboarding/contribution experience, and makes it easier to try the 0.x branch of the XB module too!

Ted “tedbow” Bowman landed the thorough validation for the component tree list: #3456024: Lift most logic out of ComponentTreeItem::preSave() and into a new validation constraint — yay!

What’s cool is that this one validation constraint is being used to validate both an Experience Builder (XB) field instance on a content entity and the default value of the XB field in config (yes, config schema validation at work!). This means slower progress, but means more reliable foundations, because there’s no separate code paths, no distinct semantics. This is crucial to meet the 14. Configuration management and 1.2 Design system (foundations), 45. Content type template variants and many other product requirements.

In other words: it is an important stepping stone towards both #3446722: Introduce an example set of representative SDC components; transition from “component list” to “component tree” and #3455629: [later phase] [META] 7. Content type templates — aka “default layouts” — affects the tree+props data model

Now that that is in, Ted will begin work next on #3460856: Create validation constraint for ComponentTreeStructure, which is a hard blocker for #3446722.

In progress

So many high-impact MRs having landed this week — I’ve simply omitted the smaller ones that are more housekeeping-esque. In closing, there are also some interesting things in progress:

… and some notable new issues:

I’m pretty confident next week will be more exciting still (well, has been … because I’m a few weeks behind on writing these posts!)

Week 10 was July 15–21, 2024.

Categories: FLOSS Project Planets

mark.ie: My Drupal Core Contributions for week-ending August 2nd, 2024

Planet Drupal - Fri, 2024-08-02 13:00

Here's what I've been working on for my Drupal contributions this week. Thanks to Code Enigma for sponsoring the time to work on these.

Categories: FLOSS Project Planets

Bits from Debian: Bits from the DPL

Planet Debian - Fri, 2024-08-02 13:00

Dear Debian community,

this are my bits from DPL written at my last day at another great DebConf.

DebConf attendance

At the beginning of July, there was some discussion with the bursary and content team about sponsoring attendees. The discussion continued at DebConf. I do not have much experience with these discussions. My summary is that while there is an honest attempt to be fair to everyone, it did not seem to work for all, and some critical points for future discussion remained. In any case, I'm thankful to the bursary team for doing such a time-draining and tedious job.

Popular packages not yet on Salsa at all

Otto Kekäläinen did some interesting investigation about Popular packages not yet on Salsa at all. I think I might provide some more up to date list soon by some UDD query which considers more recent uploads than the trends data soon. For instance wget was meanwhile moved to Salsa (thanks to Noël Köthe for this).

Keep on contacting more teams

I kept on contacting teams in July. Despite I managed to contact way less teams than I was hoping I was able to present some conclusions in the Debian Teams exchange BoF and Slide 16/23 of my Bits from the DPL talk. I intend to do further contacts next months.

Nominating Jeremy Bícha for GNOME Advisory Board

I've nominated Jeremy Bícha to GNOME Advisory Board. Jeremy has volunteered to represent Debian at GUADEC in Denver.

DebCamp / DebConf

I attended DebCamp starting from 22 July evening and had a lot of fun with other attendees. As always DebConf is some important event nearly every year for me. I enjoyed Korean food, Korean bath, nature at the costline and other things.

I had a small event without video coverage Creating web galleries including maps from a geo-tagged photo collection. At least two attendees of this workshop confirmed success in creating their own web galleries.

I used DebCamp and DebConf for several discussions. My main focus was on discussions with FTP master team members Luke Faraone, Sean Whitton, and Utkarsh Gupta. I'm really happy that the four of us absolutely agree on some proposed changes to the structure of the FTP master team, as well as changes that might be fruitful for the work of the FTP master team itself and for Debian developers regarding the processing of new packages.

My explicit thanks go to Luke Faraone, who gave a great introduction to FTP master work in their BoF. It was very instructive for the attending developers to understand how the FTP master team checks licenses and copyright and what workflow is used for accepting new packages.

In the first days of DebConf, I talked to representatives of DebConf platinum sponsor WindRiver, who announced the derivative eLxr. I warmly welcome this new derivative and look forward to some great cooperation. I also talked to the representative of our gold sponsor, Microsoft.

My first own event was the Debian Med BoF. I'd like to repeat that it might not only be interesting for people working in medicine and microbiology but always contains some hints how to work together in a team.

As said above I was trying to summarise some first results of my team contacts and got some further input from other teams in the Debian Teams exchange BoF.

Finally, I had my Bits from DPL talk. I received positive responses from attendees as well as from remote participants, which makes me quite happy. For those who were not able to join the events on-site or remotely, the videos of all events will be available on the DebConf site soon. I'd like to repeat the explicit need for some volunteers to join the Lintian team. I'd also like to point out the "Tiny tasks" initiative I'd like to start (see below).

BTW, if someone might happen to solve my quiz for the background images there is a summary page in my slides which might help to assign every slide to some DebConf. I could assume that if you pool your knowledge you can solve more than just the simple ones. Just let me know if you have some solution. You can add numbers to the rows and letters to the columns and send me:

2000/2001: Uv + Wx 2002: not attended 2003: Yz 2004: not attended 2005: 2006: not attended 2007: ... 2024: A1

This list provides some additional information for DebConfs I did not attend and when no video stream was available. It also reminds you about the one I uncovered this year and that I used two images from 2001 since I did not have one from 2000. Have fun reassembling good memories.

Tiny tasks: Bug of the day

As I mentioned in my Bits from DPL talk, I'd like to start a "Tiny tasks" effort within Debian. The first type of tasks will be the Bug of the day initiative. For those who would like to join, please join the corresponding Matrix channel. I'm curious to see how this might work out and am eager to gain some initial experiences with newcomers. I won't be available until next Monday, as I'll start traveling soon and have a family event (which is why I need to leave DebConf today after the formal dinner).

Kind regards from DebConf in Busan Andreas.

Categories: FLOSS Project Planets

Drupal In the News: Drupal launches Drupal 11, the latest version of the Open Source CMS

Planet Drupal - Fri, 2024-08-02 12:57

PORTLAND, Ore., 1 August 2024—Drupal, the most powerful open source content management system for everyone from Fortune 500 enterprise companies to mission-driven nonprofits and entrepreneurial small businesses, is launching the latest upgrade to its popular software.

Drupal 11 continues enhancing the strengths of the platform. It makes structured content, workflows, and content governance more flexible and easier for ambitious builders.

Drupal 11 is designed to empower ambitious site builders to build exceptional websites and to accelerate Drupal's innovation,” says Dries Buytaert, Founder and Project Lead of Drupal.  “With Drupal 11, we've made Drupal more intuitive, powerful, and flexible, ensuring it continues to lead in web development and digital experience creation."

This latest version of Drupal brings together code and design for a refreshed CMS navigation experience, with an updated toolbar and a collapsible left-hand menu, all designed to ensure a seamless development experience.

With new Recipes functionality, you can add new features to your website instantly by applying a set of predefined configuration. A recipe can provide anything that can be configured in Drupal, from a simple content type to a full suite of features. You can create your own recipes to share or reuse, or apply recipes created by other Drupal users. Recipes are experimental in this release but already usable and expected to be stable in 11.1.

Single-Directory Components simplify front-end development by consolidating all necessary code into a single directory, making components self-contained and effortlessly reusable.

Drupal’s high performance means it runs fast by default with swift page loading, and Drupal 11 is even faster than previous versions, running up to 50% faster on PHP 8.3. 

Accessible for every user

Drupal’s core strengths include its accessibility, security, multilingual capabilities, and flexible features. 

Thousands of developers worldwide contribute their expertise to ensure that Drupal is continuously pioneering the industry in these strengths. Supported by a global community of domain experts, it offers multilingual support with over 100 languages. 

Drupal 11 improves upon these core strengths with various features suitable for developing simple websites or complex web applications. 

Accessibility is a key strength of Drupal,” says Tim Doyle, CEO of the Drupal Association. “The Open Web is for everyone, and our continual focus on accessibility, multilingual capabilities, and flexibility is intended to ensure that Drupal is a beacon of inclusiveness in an online world where many try to build walls and barriers to entry.”

With more features coming soon

Automatic Updates and Project Browser are two key features slated for a future release of Drupal 11 and are currently under development as contributed modules. 

Drupal’s open source innovation keeps pressing ahead with the release of Drupal 11, including milestone features like Automatic Updates and Project Browser. These features will be key to the success of the new Drupal Starshot project, which will see Drupal become even easier to use for anyone wanting to unleash the power of the world’s leading enterprise CMS.” - Owen Lansbury, Drupal Association Board Chair

Automatic Updates module will apply patch-level updates to Drupal core in a separate, sandboxed copy of your site to keep you up and running without any interruptions. It can detect and report problems at every stage of the update process, so you don't have to discover them after an update is live. It automatically detects database updates and helps you run them during the process.

Project Browser will make it easy for site builders to extend the functionality, look and feel of Drupal. It provides a search interface in the Extend section of the Admin UI to find contributed modules and themes and research their capabilities. Once an extension is selected, instructions are provided on installing it on your site, all without leaving your website. 

Next steps

To start using Drupal 11, visit the Drupal 11 landing page. If you have questions about upgrading to Drupal 11, check out the FAQ page. 

To get help onboarding to Drupal 11 or creating a digital experience from the ground up, connect with one of our Drupal Certified Partners located around the world.

About Drupal and the Drupal Association

Drupal is the open source content management software trusted by millions of people and organizations worldwide. It’s supported by a network of over 10k professionals and over 100 Drupal Certified Partners. The Drupal Association is a nonprofit organization dedicated to accelerating Drupal innovation and supporting the growth of the open source community. This work delivers value to businesses, the digital community, and users of Drupal, in alignment with Drupal’s commitment to the Open Web.

Categories: FLOSS Project Planets

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