[ty] improve reachability analysis for with statement#23136
Draft
mtshiba wants to merge 4 commits intoastral-sh:mainfrom
Draft
[ty] improve reachability analysis for with statement#23136mtshiba wants to merge 4 commits intoastral-sh:mainfrom
mtshiba wants to merge 4 commits intoastral-sh:mainfrom
Conversation
Typing conformance results regressed ❌The percentage of diagnostics emitted that were expected errors decreased from 82.27% to 82.10%. The percentage of expected errors that received a diagnostic held steady at 72.99%. Summary
False positives removedDetails
False positives addedDetails
|
|
mtshiba
force-pushed
the
with-can-suppress-exception
branch
from
c37085e to
31378c6
Compare
|
| Project | Old Status | New Status | Old Return Code | New Return Code |
|---|---|---|---|---|
setuptools |
abnormal exit | abnormal exit | 2 |
2 |
Diagnostic changes:
| Lint rule | Added | Removed | Changed |
|---|---|---|---|
not-subscriptable |
106 | 1 | 0 |
unsupported-operator |
92 | 1 | 14 |
possibly-unresolved-reference |
101 | 0 | 0 |
possibly-missing-attribute |
33 | 5 | 36 |
invalid-argument-type |
29 | 1 | 7 |
no-matching-overload |
3 | 20 | 0 |
invalid-return-type |
9 | 1 | 2 |
unused-type-ignore-comment |
0 | 11 | 0 |
unresolved-attribute |
5 | 0 | 4 |
invalid-assignment |
1 | 2 | 0 |
invalid-await |
2 | 0 | 0 |
invalid-context-manager |
2 | 0 | 0 |
not-iterable |
0 | 0 | 2 |
| Total | 383 | 42 | 65 |
Member
|
Rather than testing if the value returned by |
AlexWaygood
reviewed
Feb 7, 2026
| context_manager_ty.class_member(db, "__exit__".into()) | ||
| }; | ||
| if let Place::Defined(exit) = exit_method.place | ||
| && let Some(__exit__) = exit.ty.as_function_literal() |
Member
There was a problem hiding this comment.
I think we should use try_upcast_to_callable() here rather than special-casing functions
Collaborator
Author
There was a problem hiding this comment.
In the async with case, __aexit__ is an asynchronous function, so the return type of the signature obtained with try_upcast_to_callable() is CoroutineType[..., ..., T].
Getting T from this is a bit tedious, and it's more straightforward to simply expect exit.ty to be a function literal type and take the raw signature.
Given that the specification regarding return types that suppress exceptions is very specific and conservative, it seems reasonable to treat only the case where exit.ty is a function literal as special.
Collaborator
Author
Hmm, the spec says
This seems at odds with the logic you described (perhaps the spec is more ad hoc? But that's the spec...). |
Member
|
Hmmmm I might be misremembering what mypy/pyright do here; sorry if so. I can check myself later. But what i described makes sense to me intuitively; a context manager that returns |
…ent to that of the try statement
mtshiba
force-pushed
the
with-can-suppress-exception
branch
from
7316511 to
c3c29a7
Compare
Collaborator
Author
|
I realized that the control flow of a with statement can be expressed using the same mechanism as a try statement (ref: https://peps.python.org/pep-0343/#specification-the-with-statement). class ExceptionPropagator1:
def __enter__(self) -> None: ...
def __exit__(self, exc_type, exc_value, traceback) -> Literal[False]:
return False
def propagate5(x: int | str) -> None:
if isinstance(x, int):
with ExceptionPropagator1():
raise ValueError
# TODO: should be `str`
reveal_type(x) # revealed: int | strimport sys
def propagate5_try(x: int | str) -> None:
if isinstance(x, int):
mgr = ExceptionPropagator1()
exit = type(mgr).__exit__
value = type(mgr).__enter__(mgr)
exc = True
try:
try:
raise ValueError
except:
exc = False
if not exit(mgr, *sys.exc_info()):
raise
finally:
if exc:
exit(mgr, None, None, None)
# TODO: should be `str`
reveal_type(x) # revealed: int | str |
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
2 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.
Summary
This PR closes astral-sh/ty#152.
Test Plan
mdtest updated