[ty] struct.unpack return type inference#22562
Merged
sharkdp merged 6 commits intoastral-sh:mainfrom Feb 6, 2026
Merged
Conversation
sakgoyal
requested review from
AlexWaygood,
Gankra,
MichaReiser,
carljm,
dcreager and
sharkdp
as code owners
sakgoyal
changed the title
struct.unpack Implementation attempt (with AI)struct.unpack return type inference
Typing conformance resultsNo changes detected ✅ |
|
This comment was marked as resolved.
This comment was marked as resolved.
This comment was marked as resolved.
This comment was marked as resolved.
This comment was marked as resolved.
This comment was marked as resolved.
AlexWaygood
changed the title
struct.unpack return type inferencestruct.unpack return type inference
oconnor663
reviewed
Jan 16, 2026
sakgoyal
force-pushed
the
structunpack
branch
from
f7dd858 to
ac47c91
Compare
Contributor
Author
|
Rolled up into 1 commit to make git history nicer if this gets merged |
MichaReiser
reviewed
Jan 19, 2026
sharkdp
approved these changes
Feb 6, 2026
Contributor
sharkdp
left a comment
sharkdp
left a comment
There was a problem hiding this comment.
Thank you very much, this looks great.
I made some minor adjustments myself (proper thresholding, whitespace handling, some more tests, some refactoring).
| elements.push(ty); | ||
| } else { | ||
| // To prevent OOM errors, we cap the number of repetitions by escaping to Unknown. | ||
| if count >= 2 ^ 16 { |
Contributor
There was a problem hiding this comment.
2 ^ 16 means 2 XOR 16 in Rust, so this is equivalent to count >= 18 (https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=a290d2ec64af9b8124fe1a55c41052ca), probably not what you intended.
2¹⁶ would actually be way too high of a limit, I think. That would mean we would construct tuple types with 65536 entries. I'll change the limit to 32 for now and add some tests that this thresholding kicks in at the right position.
| let mut escaped = false; | ||
| let mut chars = core.chars().peekable(); | ||
|
|
||
| while chars.peek().is_some() { |
Contributor
There was a problem hiding this comment.
We could also skip whitespace here:
Whitespace characters between formats are ignored; a count and its format must not contain whitespace though.
|
| Lint rule | Added | Removed | Changed |
|---|---|---|---|
unsupported-operator |
80 | 70 | 49 |
not-subscriptable |
96 | 1 | 0 |
possibly-missing-attribute |
24 | 5 | 35 |
invalid-argument-type |
9 | 3 | 9 |
no-matching-overload |
0 | 21 | 0 |
invalid-return-type |
0 | 5 | 2 |
invalid-assignment |
4 | 1 | 1 |
not-iterable |
0 | 0 | 2 |
unresolved-attribute |
0 | 1 | 0 |
| Total | 213 | 107 | 98 |
Contributor
|
There are a few new diagnostics in the ecosystem (filtering out all the non-deterministic diagnosic noise), and they all look like true positives to me — nice! Looks like this will help users find some bugs. |
ngnpope
added a commit
to ngnpope/ruff
that referenced
this pull request
Feb 6, 2026
Recently the `D` and `F` format characters for complex types were added to `struct.unpack()`. See the following links for details: - https://docs.python.org/3/whatsnew/3.14.html#struct - https://docs.python.org/3/library/struct.html#format-characters Refs astral-sh/ty#2437 Refs astral-sh#22562
ngnpope
added a commit
to ngnpope/ruff
that referenced
this pull request
Feb 6, 2026
Recently the `D` and `F` format characters for complex types were added to `struct.unpack()`. See the following links for details: - https://docs.python.org/3/whatsnew/3.14.html#struct - https://docs.python.org/3/library/struct.html#format-characters This adds support for these new formats when using Python 3.14+ Refs astral-sh/ty#2437 Refs astral-sh#22562
carljm
pushed a commit
that referenced
this pull request
Feb 7, 2026
## Summary Recently the `D` and `F` format characters for complex types were added to `struct.unpack()`. See the following links for details: - https://docs.python.org/3/whatsnew/3.14.html#struct - https://docs.python.org/3/library/struct.html#format-characters This adds support for these new formats when using Python 3.14+ Refs astral-sh/ty#2437 Refs #22562 ## Test Plan Update to existing mdtest.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
8 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Fixes astral-sh/ty#2437
Summary
Allow the checker to analyze the format string for
struct.unpackto ensure correct types are generated instead ofAny.Test Plan
Added mdtest cases from original issue.