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Remove ByteString from typing and collections.abc #118803

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Remove ByteString from typing and collections.abc#118803
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sobolevnAlexWaygood
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3.14bugs and security fixestopic-typingtype-featureA feature request or enhancement

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@sobolevn
sobolevn
opened on May 8, 2024

Feature or enhancement

It was deprecated and scheduled for removal in 3.14

Original issue: #91896
Ref: 09b7695

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  1. sobolevn
    added
    type-featureA feature request or enhancement
    topic-typing
    3.14bugs and security fixes
    on May 8, 2024
  2. sobolevn
    self-assigned this
    on May 8, 2024
  3. sobolevn
    added a commit that references this issue on May 8, 2024

    pythongh-118803: Remove `ByteString` from `typing` and `collections.abc`

    7cf1579
  4. AlexWaygood
    added a commit that references this issue on May 8, 2024

    gh-118803: Remove `ByteString` from `typing` and `collections.abc` (#…

    2f4db5a
  5. AlexWaygood
    closed this as completedon May 8, 2024

  6. cdce8p commented on May 26, 2025

    @cdce8p
    cdce8p
    on May 26, 2025
    Contributor

    Tbh I was a bit surprised that it didn't raise any DeprecationWarning on 3.13. Looking at #118804 it seems that was only emitted on isinstance checks. Most examples I've seen while testing 3.14 just import it at runtime to use as annotation.

    It's a bit unfortunate to not have gotten a warning for it earlier as a few packages will now require immediate fixes for 3.14. Not sure if it would be worth it to revert the removal and add a proper DeprecationWarning on import (i.e. in typing.__getattr__)?

  7. JelleZijlstra commented on May 26, 2025

    @JelleZijlstra
    JelleZijlstra
    on May 26, 2025
    Member

    I'd be OK with that. This sort of removal can be pretty disruptive since libraries using it will usually be using a from import, so users who need those libraries will be completely unable to even import the library on 3.14.

    What are some examples of libraries still using this?

  8. AlexWaygood commented on May 28, 2025

    @AlexWaygood
    AlexWaygood
    on May 28, 2025
    Member

    I'm also fine with doing a longer deprecation period here. The reason we didn't emit deprecation warnings when it was imported/accessed from typing.py initially was that it's included in typing.__all__, which means that from typing import * would have led to a deprecation warning being emitted. We realised that doing that is actually fairly common, and we couldn't remove it from __all__ because that itself was a breaking change.

    Now that we've had deprecation warnings in the docs for 2 years, though (and some deprecation warnings at runtime), I think it would be fine to remove ByteString from typing.__all__, remove ByteString from collections.abc.__all__, and emit more aggressive deprecation warnings that trigger when you import it from typing or access it as an attribute from the module. It's still breaking (people will get NameErrors if they were relying on from typing import * to import ByteString for them), but it's much less breaking than what we have now, which is ByteString no longer existing at all.

  9. AlexWaygood commented on May 28, 2025

    @AlexWaygood
    AlexWaygood
    on May 28, 2025
    Member

    What are some examples of libraries still using this?

    It was a while back (and they obviously no longer use it following my PR), but I was pretty concerned when aiohttp said that they hadn't seen any deprecation warnings about this in aio-libs/aiohttp#8408 (comment). I meant to propose extending the deprecation period, but lost track of it :-(

  10. cdce8p commented on May 28, 2025

    @cdce8p
    cdce8p
    on May 28, 2025
    Contributor

    What are some examples of libraries still using this?

    I've only seen it a couple of times so far. Most cases have already been fixed for some time now:

  11. JelleZijlstra commented on May 28, 2025

    @JelleZijlstra
    JelleZijlstra
    on May 28, 2025
    Member

    Anyone interested in sending a PR to restore it for 3.14?

  12. JelleZijlstra
    reopened this on May 28, 2025

  13. sobolevn commented on May 29, 2025

    @sobolevn
    sobolevn
    on May 29, 2025
    MemberAuthor

    I think that we should check top 10000 packages for its usages. If there are many existing ones - it might be a good idea to restore it. But, if there are just several - then we should probably move forward, it was deprecated for 5 versions already, there was a lot of time to change the code .. deprecated-removed:: 3.9 3.14. It is not hard to fix in the library code as ByteString = bytes | bytearray.

  14. 18 remaining items

  15. AlexWaygood
    added a commit that references this issue on Sep 16, 2025

    Revert "gh-118803: Remove `ByteString` from `typing` and `collections…

    530ddd3
  16. miss-islington
    added a commit that references this issue on Sep 16, 2025

    Revert "pythongh-118803: Remove `ByteString` from `typing` and `colle…

    997a9b9
  17. hugovk
    added a commit that references this issue on Sep 17, 2025

    [3.14] Revert "gh-118803: Remove `ByteString` from `typing` and `coll…

    7bba99c
  18. hugovk
    removed
    release-blocker
    on Sep 17, 2025
  19. AlexWaygood
    added 3 commits that reference this issue on Sep 18, 2025

    pythongh-118803: Improve documentation around `ByteString` deprecation

    45fbbc6

    pythongh-118803: Make `ByteString` deprecations louder; remove `ByteS…

    b508dd0

    gh-118803: Improve documentation around `ByteString` deprecation (#13…

    4305cc3
  20. miss-islington
    added a commit that references this issue on Sep 18, 2025

    pythongh-118803: Improve documentation around `ByteString` deprecation (

    9835841
  21. hugovk
    added a commit that references this issue on Sep 18, 2025

    [3.14] gh-118803: Improve documentation around `ByteString` deprecati…

    665a349
  22. AlexWaygood
    added 2 commits that reference this issue on Sep 18, 2025

    [3.13] gh-118803: Improve documentation around `ByteString` deprecati…

    8246e25

    gh-118803: Make `ByteString` deprecations louder; remove `ByteString`…

    293b05c

  23. AlexWaygood commented on Sep 18, 2025

    @AlexWaygood
    AlexWaygood
    on Sep 18, 2025
    Member

    We've now done everything we plan to do here until 3.17

  24. AlexWaygood
    closed this as completedon Sep 18, 2025
  25. github-project-automation
    moved this from Todo to Done in Release and Deferred blockers 🚫on Sep 18, 2025
  26. AlexWaygood
    added a commit that references this issue on Sep 19, 2025

    [3.13] gh-118803: Fixup a few references in the 3.13 branch to the in…

    8aa8561
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