## Summary
Add a micro-benchmark for the code pattern observed in
https://github.com/astral-sh/ty/issues/362.
This currently takes around 1 second on my machine.
## Test Plan
```bash
cargo bench -p ruff_benchmark -- 'ty_micro\[many_tuple' --sample-size 10
```
Follows on from (and depends on)
https://github.com/astral-sh/ruff/pull/18021.
This updates our function specialization inference to infer type
mappings from parameters that are generic protocols.
For now, this only works when the argument _explicitly_ implements the
protocol by listing it as a base class. (We end up using exactly the
same logic as for generic classes in #18021.) For this to work with
classes that _implicitly_ implement the protocol, we will have to check
the types of the protocol members (which we are not currently doing), so
that we can infer the specialization of the protocol that the class
implements.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
Understand that `__file__` is always set and a `str` when looked up as
an implicit global from a Python file we are type checking.
## Test Plan
mdtests
## Summary
Fix the lookup of `submodule`s in cases where the `parent` module has a
self-referential import like `from parent import submodule`. This allows
us to infer proper types for many symbols where we previously inferred
`Never`. This leads to many new false (and true) positives across the
ecosystem because the fact that we previously inferred `Never` shadowed
a lot of problems. For example, we inferred `Never` for `os.path`, which
is why we now see a lot of new diagnostics related to `os.path.abspath`
and similar.
```py
import os
reveal_type(os.path) # previously: Never, now: <module 'os.path'>
```
closes https://github.com/astral-sh/ty/issues/261
closes https://github.com/astral-sh/ty/issues/307
## Ecosystem analysis
```
┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━━┓
┃ Diagnostic ID ┃ Severity ┃ Removed ┃ Added ┃ Net Change ┃
┡━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━━┩
│ call-non-callable │ error │ 1 │ 5 │ +4 │
│ call-possibly-unbound-method │ warning │ 6 │ 26 │ +20 │
│ invalid-argument-type │ error │ 26 │ 94 │ +68 │
│ invalid-assignment │ error │ 18 │ 46 │ +28 │
│ invalid-context-manager │ error │ 9 │ 4 │ -5 │
│ invalid-raise │ error │ 1 │ 1 │ 0 │
│ invalid-return-type │ error │ 3 │ 20 │ +17 │
│ invalid-super-argument │ error │ 4 │ 0 │ -4 │
│ invalid-type-form │ error │ 573 │ 0 │ -573 │
│ missing-argument │ error │ 2 │ 10 │ +8 │
│ no-matching-overload │ error │ 0 │ 715 │ +715 │
│ non-subscriptable │ error │ 0 │ 35 │ +35 │
│ not-iterable │ error │ 6 │ 7 │ +1 │
│ possibly-unbound-attribute │ warning │ 14 │ 31 │ +17 │
│ possibly-unbound-import │ warning │ 13 │ 0 │ -13 │
│ possibly-unresolved-reference │ warning │ 0 │ 8 │ +8 │
│ redundant-cast │ warning │ 1 │ 0 │ -1 │
│ too-many-positional-arguments │ error │ 2 │ 0 │ -2 │
│ unknown-argument │ error │ 2 │ 0 │ -2 │
│ unresolved-attribute │ error │ 583 │ 304 │ -279 │
│ unresolved-import │ error │ 0 │ 96 │ +96 │
│ unsupported-operator │ error │ 0 │ 17 │ +17 │
│ unused-ignore-comment │ warning │ 29 │ 2 │ -27 │
├───────────────────────────────┼──────────┼─────────┼───────┼────────────┤
│ TOTAL │ │ 1293 │ 1421 │ +128 │
└───────────────────────────────┴──────────┴─────────┴───────┴────────────┘
Analysis complete. Found 23 unique diagnostic IDs.
Total diagnostics removed: 1293
Total diagnostics added: 1421
Net change: +128
```
* We see a lot of new errors (`no-matching-overload`) related to
`os.path.dirname` and other `os.path` operations because we infer `str |
None` for `__file__`, but many projects use something like
`os.path.dirname(__file__)`.
* We also see many new `unresolved-attribute` errors related to the fact
that we now infer proper module types for some imports (e.g. `import
kornia.augmentation as K`), but we don't allow implicit imports (e.g.
accessing `K.auto.operations` without also importing `K.auto`). See
https://github.com/astral-sh/ty/issues/133.
* Many false positive `invalid-type-form` are removed because we now
infer the correct type for some type expression instead of `Never`,
which is not valid in a type annotation/expression context.
## Test Plan
Added new Markdown tests
## Summary
If the user tries to use a new builtin on an old Python version, tell
them what Python version the builtin was added on, what our inferred
Python version is for their project, and what configuration settings
they can tweak to fix the error.
## Test Plan
Snapshots and screenshots:

First take on a contributing guide for `ty`. Lots of it is copied from
the existing Ruff contribution guide.
I've put this in Ruff repo, since I think a contributing guide belongs
where the code is. I also updated the Ruff contributing guide to link to
the `ty` one.
Once this is merged, we can also add a link from the `CONTRIBUTING.md`
in ty repo (which focuses on making contributions to things that are
actually in the ty repo), to this guide.
I also updated the pull request template to mention that it might be a
ty PR, and mention the `[ty]` PR title prefix.
Feel free to update/modify/merge this PR before I'm awake tomorrow.
---------
Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com>
Co-authored-by: David Peter <mail@david-peter.de>
Fixes: https://github.com/astral-sh/ty/issues/92
## Summary
We currently get a `invalid-argument-type` error when using
`dataclass.fields` on a dataclass, because we do not synthesize the
`__dataclass_fields__` member.
This PR fixes this diagnostic.
Note that we do not yet model the `Field` type correctly. After that is
done, we can assign a more precise `tuple[Field, ...]` type to this new
member.
## Test Plan
New mdtest.
---------
Co-authored-by: David Peter <mail@david-peter.de>
This updates our function specialization inference to infer type
mappings from parameters that are generic aliases, e.g.:
```py
def f[T](x: list[T]) -> T: ...
reveal_type(f(["a", "b"])) # revealed: str
```
Though note that we're still inferring the type of list literals as
`list[Unknown]`, so for now we actually need something like the
following in our tests:
```py
def _(x: list[str]):
reveal_type(f(x)) # revealed: str
```
We were not inducting into instance types and subclass-of types when
looking for legacy typevars, nor when apply specializations.
This addresses
https://github.com/astral-sh/ruff/pull/17832#discussion_r2081502056
```py
from __future__ import annotations
from typing import TypeVar, Any, reveal_type
S = TypeVar("S")
class Foo[T]:
def method(self, other: Foo[S]) -> Foo[T | S]: ... # type: ignore[invalid-return-type]
def f(x: Foo[Any], y: Foo[Any]):
reveal_type(x.method(y)) # revealed: `Foo[Any | S]`, but should be `Foo[Any]`
```
We were not detecting that `S` made `method` generic, since we were not
finding it when searching the function signature for legacy typevars.
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
If a try-catch block guards the names, we don't raise warnings. During
this change, I discovered that some of the replacement types were
missed. Thus, I extend the fix to types other than AutoImport as well
## Test Plan
<!-- How was it tested? -->
Test fixtures are added and updated.
## Summary
Updates the `--python` flag to accept Python executables in virtual
environments. Notably, we do not query the executable and it _must_ be
in a canonical location in a virtual environment. This is pretty naive,
but solves for the trivial case of `ty check --python .venv/bin/python3`
which will be a common mistake (and `ty check --python $(which python)`)
I explored this while trying to understand Python discovery in ty in
service of https://github.com/astral-sh/ty/issues/272, I'm not attached
to it, but figure it's worth sharing.
As an alternative, we can add more variants to the
`SearchPathValidationError` and just improve the _error_ message, i.e.,
by hinting that this looks like a virtual environment and suggesting the
concrete alternative path they should provide. We'll probably want to do
that for some other cases anyway (e.g., `3.13` as described in the
linked issue)
This functionality is also briefly mentioned in
https://github.com/astral-sh/ty/issues/193
Closes https://github.com/astral-sh/ty/issues/318
## Test Plan
e.g.,
```
uv run ty check --python .venv/bin/python3
```
needs test coverage still
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
The existing implementation of RUF060 (InEmptyCollection) is not
recursive, meaning that although set([]) results in an empty collection,
the existing code fails it because set is taking an argument.
The updated implementation allows set and frozenset to take empty
collection as positional argument (which results in empty
set/frozenset).
## Test Plan
Added test cases for recursive cases + updated snapshot (see RUF060.py).
---------
Co-authored-by: Marcus Näslund <marcus.naslund@kognity.com>
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## Summary
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Fixes#17776.
This PR also handles all other `PTH*` rules that don't support file
descriptors.
## Test Plan
<!-- How was it tested? -->
Update existing tests.
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## Summary
We can only guarantee the safety of the autofix for number literals, all
other cases may change the runtime behaviour of the program or introduce
a syntax error. For the cases reported in the issue that would result in
a syntax error, I disabled the autofix.
Follow-up of #17661.
Fixes#16472.
<!-- What's the purpose of the change? What does it do, and why? -->
## Test Plan
Snapshot tests.
<!-- How was it tested? -->
Function literals have an optional specialization, which is applied to
the parameter/return type annotations lazily when the function's
signature is requested. We were previously only applying this
specialization to the final overload of an overloaded function.
This manifested most visibly for `list.__add__`, which has an overloaded
definition in the typeshed:
b398b83631/crates/ty_vendored/vendor/typeshed/stdlib/builtins.pyi (L1069-L1072)
Closes https://github.com/astral-sh/ty/issues/314
## Summary
I found this bug while working on #18041. The following code leads to
infinite recursion.
```python
from ty_extensions import is_disjoint_from, static_assert, TypeOf
class C:
@property
def prop(self) -> int:
return 1
static_assert(not is_disjoint_from(int, TypeOf[C.prop]))
```
The cause is a trivial missing binding in `is_disjoint_from`. This PR
fixes the bug and adds a test case (this is a simple fix and may not
require a new test case?).
## Test Plan
A new test case is added to
`mdtest/type_properties/is_disjoint_from.md`.
## Summary
Added version 3.14 to the script generating the `known_stdlib.rs` file.
Rebuilt the known stdlibs with latest version (2025.5.10) of [stdlibs
Python lib](https://pypi.org/project/stdlibs/) (which added support for
3.14.0b1).
_Note: Python 3.14 is now in [feature
freeze](https://peps.python.org/pep-0745/) so the modules in stdlib
should be stable._
_See also: #15506_
## Test Plan
The following command has been run. Using for tests the `compression`
module which been introduced with Python 3.14.
```sh
ruff check --no-cache --select I001 --target-version py314 --fix
```
With ruff 0.11.9:
```python
import base64
import datetime
import compression
print(base64, compression, datetime)
```
With this PR:
```python
import base64
import compression
import datetime
print(base64, compression, datetime)
```
## Summary
`KnownClass::Range`, `KnownInstanceType::Any` and `ClassBase::any()` are
no longer used or useful: all our tests pass with them removed.
`KnownModule::Abc` _is_ now used outside of tests, however, so I removed
the `#[allow(dead_code)]` branch above that variant.
## Test Plan
`cargo test -p ty_python_semantic`
Following #17991, removes some of
https://github.com/astral-sh/ruff/pull/17222 which is no longer strictly
necessary. I don't actually think it's that ugly to have around? no
strong feelings on retaining it or not.
Follow-up to https://github.com/astral-sh/ruff/pull/17991 ensuring we do
not allow detection of system environments when the origin is
`VIRTUAL_ENV` or a discovered `.venv` directory — i.e., those always
require a `pyvenv.cfg` file.
Adds test coverage for https://github.com/astral-sh/ruff/pull/17991,
which includes some minor refactoring of the virtual environment test
infrastructure.
I tried to minimize stylistic changes, but there are still a few because
I was a little confused by the setup. I could see this evolving more in
the future, as I don't think the existing model can capture all the test
coverage I'm looking for.
This adds basic support for non-virtual Python environments by accepting
a directory without a `pyvenv.cfg` which allows existing, subsequent
site-packages discovery logic to succeed. We can do better here in the
long-term, by adding more eager validation (for error messages) and
parsing the Python version from the discovered site-packages directory
(which isn't relevant yet, because we don't use the discovered Python
version from virtual environments as the default `--python-version` yet
either).
Related
- https://github.com/astral-sh/ty/issues/265
- https://github.com/astral-sh/ty/issues/193
You can review this commit by commit if it makes you happy.
I tested this manually; I think refactoring the test setup is going to
be a bit more invasive so I'll stack it on top (see
https://github.com/astral-sh/ruff/pull/17996).
```
❯ uv run ty check --python /Users/zb/.local/share/uv/python/cpython-3.10.17-macos-aarch64-none/ -vv example
2025-05-09 12:06:33.685911 DEBUG Version: 0.0.0-alpha.7 (f9c4c8999 2025-05-08)
2025-05-09 12:06:33.685987 DEBUG Architecture: aarch64, OS: macos, case-sensitive: case-insensitive
2025-05-09 12:06:33.686002 DEBUG Searching for a project in '/Users/zb/workspace/ty'
2025-05-09 12:06:33.686123 DEBUG Resolving requires-python constraint: `>=3.8`
2025-05-09 12:06:33.686129 DEBUG Resolved requires-python constraint to: 3.8
2025-05-09 12:06:33.686142 DEBUG Project without `tool.ty` section: '/Users/zb/workspace/ty'
2025-05-09 12:06:33.686147 DEBUG Searching for a user-level configuration at `/Users/zb/.config/ty/ty.toml`
2025-05-09 12:06:33.686156 INFO Defaulting to python-platform `darwin`
2025-05-09 12:06:33.68636 INFO Python version: Python 3.8, platform: darwin
2025-05-09 12:06:33.686375 DEBUG Adding first-party search path '/Users/zb/workspace/ty'
2025-05-09 12:06:33.68638 DEBUG Using vendored stdlib
2025-05-09 12:06:33.686634 DEBUG Discovering site-packages paths from sys-prefix `/Users/zb/.local/share/uv/python/cpython-3.10.17-macos-aarch64-none` (`--python` argument')
2025-05-09 12:06:33.686667 DEBUG Attempting to parse virtual environment metadata at '/Users/zb/.local/share/uv/python/cpython-3.10.17-macos-aarch64-none/pyvenv.cfg'
2025-05-09 12:06:33.686671 DEBUG Searching for site-packages directory in `sys.prefix` path `/Users/zb/.local/share/uv/python/cpython-3.10.17-macos-aarch64-none`
2025-05-09 12:06:33.686702 DEBUG Resolved site-packages directories for this environment are: ["/Users/zb/.local/share/uv/python/cpython-3.10.17-macos-aarch64-none/lib/python3.10/site-packages"]
2025-05-09 12:06:33.686706 DEBUG Adding site-packages search path '/Users/zb/.local/share/uv/python/cpython-3.10.17-macos-aarch64-none/lib/python3.10/site-packages'
...
❯ uv run ty check --python /tmp -vv example
2025-05-09 15:36:10.819416 DEBUG Version: 0.0.0-alpha.7 (f9c4c8999 2025-05-08)
2025-05-09 15:36:10.819708 DEBUG Architecture: aarch64, OS: macos, case-sensitive: case-insensitive
2025-05-09 15:36:10.820118 DEBUG Searching for a project in '/Users/zb/workspace/ty'
2025-05-09 15:36:10.821652 DEBUG Resolving requires-python constraint: `>=3.8`
2025-05-09 15:36:10.821667 DEBUG Resolved requires-python constraint to: 3.8
2025-05-09 15:36:10.8217 DEBUG Project without `tool.ty` section: '/Users/zb/workspace/ty'
2025-05-09 15:36:10.821888 DEBUG Searching for a user-level configuration at `/Users/zb/.config/ty/ty.toml`
2025-05-09 15:36:10.822072 INFO Defaulting to python-platform `darwin`
2025-05-09 15:36:10.822439 INFO Python version: Python 3.8, platform: darwin
2025-05-09 15:36:10.822773 DEBUG Adding first-party search path '/Users/zb/workspace/ty'
2025-05-09 15:36:10.822929 DEBUG Using vendored stdlib
2025-05-09 15:36:10.829872 DEBUG Discovering site-packages paths from sys-prefix `/tmp` (`--python` argument')
2025-05-09 15:36:10.829911 DEBUG Attempting to parse virtual environment metadata at '/private/tmp/pyvenv.cfg'
2025-05-09 15:36:10.829917 DEBUG Searching for site-packages directory in `sys.prefix` path `/private/tmp`
ty failed
Cause: Invalid search path settings
Cause: Failed to discover the site-packages directory: Failed to search the `lib` directory of the Python installation at `sys.prefix` path `/private/tmp` for `site-packages`
```
## Summary
Suppress false positives for uses of PEP-695 `ParamSpec` in `Callable`
annotations:
```py
from typing_extensions import Callable
def f[**P](c: Callable[P, int]):
pass
```
addresses a comment here:
https://github.com/astral-sh/ty/issues/157#issuecomment-2859284721
## Test Plan
Adapted Markdown tests
Re: #17526
## Summary
Add integration test for semantic syntax for `IrrefutableCasePattern`,
`SingleStarredAssignment`, `WriteToDebug`, and `InvalidExpression`.
## Notes
- Following @ntBre's suggestion, I will keep the test coming in batches
like this over the next few days in separate PRs to keep the review load
per PR manageable while also not spamming too many.
- I did not add a test for `del __debug__` which is one of the examples
in `crates/ruff_python_parser/src/semantic_errors.rs:1051`.
For python version `<= 3.8` there is no error and for `>=3.9` the error
is not `WriteToDebug` but `SyntaxError: cannot delete __debug__ on
Python 3.9 (syntax was removed in 3.9)`.
- The `blacken-docs` bypass is necessary because otherwise the test does
not pass pre-commit checks; but we want to check for this faulty syntax.
<!-- What's the purpose of the change? What does it do, and why? -->
## Test Plan
This is a test.
Summary
--
This was suggested on Discord, I hope this is roughly what we had in
mind. I took the message from the ty README, but I'm more than happy to
update it. Otherwise I just tried to mimic the appearance of the `ruff
analyze graph` warning (although I'm realizing now the whole text is
bold for ruff).
Test Plan
--
New warnings in the CLI tests. I thought this might be undesirable but
it looks like uv did the same thing
(https://github.com/astral-sh/uv/pull/6166).

This makes one very simple change: we report all call binding
errors from each union variant.
This does result in duplicate-seeming diagnostics. For example,
when two union variants are invalid for the same reason.
## Summary
Adds a simple progress bar for the `ty check` CLI command. The style is
taken from uv, and like uv the bar is always shown - for smaller
projects it is fast enough that it isn't noticeable. We could
alternatively hide it completely based on some heuristic for the number
of files, or only show it after some amount of time.
I also disabled it when `--watch` is passed, cancelling inflight checks
was leading to zombie progress bars. I think we can fix this by using
[`MultiProgress`](https://docs.rs/indicatif/latest/indicatif/struct.MultiProgress.html)
and managing all the bars globally, but I left that out for now.
Resolves https://github.com/astral-sh/ty/issues/98.
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## Summary
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* `airflow.models.Connection` → `airflow.sdk.Connection`
* `airflow.models.Variable` → `airflow.sdk.Variable`
## Test Plan
<!-- How was it tested? -->
The test fixtures has been updated (see the first commit for easier
review)
This does a deeper removal of the `lint:` prefix by removing the
`DiagnosticId::as_str` method and replacing it with `as_concise_str`. We
remove the associated error type and simplify the `Display` impl for
`DiagnosticId` as well.
This turned out to catch a `lint:` that was still in the diagnostic
output: the part that says why a lint is enabled.
We just set the ID on the `Message` and it just does what we want in
this case. I think I didn't do this originally because I was trying to
preserve the existing rendering? I'm not sure. I might have just missed
this method.
In a subsequent commit, we're going to start using `annotate-snippets`'s
functionality for diagnostic IDs in the rendering. As part of doing
that, I wanted to remove this special casing of an empty message. I did
that independently to see what, if anything, would change. (The changes
look fine to me. They'll be tweaked again in the next commit along with
a bunch of others.)
## Summary
Use a self-reference "marker" ~~and fixpoint iteration~~ to solve the
stack overflow problems with recursive protocols. This is not pretty and
somewhat tedious, but seems to work fine. Much better than all my
fixpoint-iteration attempts anyway.
closes https://github.com/astral-sh/ty/issues/93
## Test Plan
New Markdown tests.
## Summary
Add cycle handling for `try_metaclass` and `pep695_generic_context`
queries, as well as adjusting the cycle handling for `try_mro` to ensure
that it short-circuits on cycles and won't grow MROs indefinitely.
This reduces the number of failing fuzzer seeds from 68 to 17. The
latter count includes fuzzer seeds 120, 160, and 335, all of which
previously panicked but now either hang or are very slow; I've
temporarily skipped those seeds in the fuzzer until I can dig into that
slowness further.
This also allows us to move some more ecosystem projects from `bad.txt`
to `good.txt`, which I've done in
https://github.com/astral-sh/ruff/pull/17903
## Test Plan
Added mdtests.
@AlexWaygood pointed out that the `SliceLiteral` type variant was
originally created to handle slices before we had generics.
https://github.com/astral-sh/ruff/pull/17927#discussion_r2078115787
Now that we _do_ have generics, we can use a specialization of the
`slice` builtin type for slice literals.
This depends on https://github.com/astral-sh/ruff/pull/17956, since we
need to make sure that all typevar defaults are fully substituted when
specializing `slice`.
It's possible for a typevar to list another typevar as its default
value:
```py
class C[T, U = T]: ...
```
When specializing this class, if a type isn't provided for `U`, we would
previously use the default as-is, leaving an unspecialized `T` typevar
in the specialization. Instead, we want to use what `T` is mapped to as
the type of `U`.
```py
reveal_type(C()) # revealed: C[Unknown, Unknown]
reveal_type(C[int]()) # revealed: C[int, int]
reveal_type(C[int, str]()) # revealed: C[int, str]
```
This is especially important for the `slice` built-in type.
## Summary
This PR is a first step toward integration of the new `Diagnostic` type
into ruff. There are two main changes:
- A new `UnifiedFile` enum wrapping `File` for red-knot and a
`SourceFile` for ruff
- ruff's `Message::SyntaxError` variant is now a `Diagnostic` instead of
a `SyntaxErrorMessage`
The second of these changes was mostly just a proof of concept for the
first, and it went pretty smoothly. Converting `DiagnosticMessage`s will
be most of the work in replacing `Message` entirely.
## Test Plan
Existing tests, which show no changes.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Co-authored-by: Micha Reiser <micha@reiser.io>
Summary
--
This PR resolves both the typing-related and syntax error TODOs added in
#17563 by tracking a set of `global` bindings for each scope. As
discussed below, we avoid the additional AST traversal from ruff by
collecting `Name`s from `global` statements while building the semantic
index and emit a syntax error if the `Name` is already bound in the
current scope at the point of the `global` statement. This has the
downside of separating the error from the `SemanticSyntaxChecker`, but I
plan to explore using this approach in the `SemanticSyntaxChecker`
itself as a follow-up. It seems like this may be a better approach for
ruff as well.
Test Plan
--
Updated all of the related mdtests to remove the TODOs (and add quotes I
forgot on the messages).
There is one remaining TODO, but it requires `nonlocal` support, which
isn't even incorporated into the `SemanticSyntaxChecker` yet.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
Fixes: astral-sh/ty#159
This PR adds support for using `Self` in methods.
When the type of an annotation is `TypingSelf` it is converted to a type
var based on:
https://typing.python.org/en/latest/spec/generics.html#self
I just skipped Protocols because it had more problems and the tests was
not useful.
Also I need to create a follow up PR that implicitly assumes `self`
argument has type `Self`.
In order to infer the type in the `in_type_expression` method I needed
to have scope id and semantic index available. I used the idea from
[this PR](https://github.com/astral-sh/ruff/pull/17589/files) to pass
additional context to this method.
Also I think in all places that `in_type_expression` is called we need
to have this context because `Self` can be there so I didn't split the
method into one version with context and one without.
## Test Plan
Added new tests from spec.
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
Co-authored-by: Carl Meyer <carl@astral.sh>
#17897 added variance handling for legacy typevars — but they were only
being considered when checking generic aliases of the same class:
```py
class A: ...
class B(A): ...
class C[T]: ...
static_assert(is_subtype_of(C[B], C[A]))
```
and not for generic subclasses:
```py
class D[U](C[U]): ...
static_assert(is_subtype_of(D[B], C[A]))
```
Now we check those too!
Closes https://github.com/astral-sh/ty/issues/101
Fixes#17867
## Summary
The CPython parser does not allow generator expressions which are the
sole arguments in an argument list to have a trailing comma.
With this change, we start flagging such instances.
## Test Plan
Added new inline tests.
## Summary
We now expect the client to send initialization options to opt-in to
experimental (but LSP-standardized) features, like completion support.
Specifically, the client should set `"experimental.completions.enable":
true`.
Closes https://github.com/astral-sh/ty/issues/74.
## Summary
This PR adds support for the `__all__` module variable.
Reference spec:
https://typing.python.org/en/latest/spec/distributing.html#library-interface-public-and-private-symbols
This PR adds a new `dunder_all_names` query that returns a set of
`Name`s defined in the `__all__` variable of the given `File`. The query
works by implementing the `StatementVisitor` and collects all the names
by recognizing the supported idioms as mentioned in the spec. Any idiom
that's not recognized are ignored.
The current implementation is minimum to what's required for us to
remove all the false positives that this is causing. Refer to the
"Follow-ups" section below to see what we can do next. I'll a open
separate issue to keep track of them.
Closes: astral-sh/ty#106Closes: astral-sh/ty#199
### Follow-ups
* Diagnostics:
* Add warning diagnostics for unrecognized `__all__` idioms, `__all__`
containing non-string element
* Add an error diagnostic for elements that are present in `__all__` but
not defined in the module. This could lead to runtime error
* Maybe we should return `<type>` instead of `Unknown | <type>` for
`module.__all__`. For example:
https://playknot.ruff.rs/2a6fe5d7-4e16-45b1-8ec3-d79f2d4ca894
* Mark a symbol that's mentioned in `__all__` as used otherwise it could
raise (possibly in the future) "unused-name" diagnostic
Supporting diagnostics will require that we update the return type of
the query to be something other than `Option<FxHashSet<Name>>`,
something that behaves like a result and provides a way to check whether
a name exists in `__all__`, loop over elements in `__all__`, loop over
the invalid elements, etc.
## Ecosystem analysis
The following are the maximum amount of diagnostics **removed** in the
ecosystem:
* "Type <module '...'> has no attribute ..."
* `collections.abc` - 14
* `numpy` - 35534
* `numpy.ma` - 296
* `numpy.char` - 37
* `numpy.testing` - 175
* `hashlib` - 311
* `scipy.fft` - 2
* `scipy.stats` - 38
* "Module '...' has no member ..."
* `collections.abc` - 85
* `numpy` - 508
* `numpy.testing` - 741
* `hashlib` - 36
* `scipy.stats` - 68
* `scipy.interpolate` - 7
* `scipy.signal` - 5
The following modules have dynamic `__all__` definition, so `ty` assumes
that `__all__` doesn't exists in that module:
* `scipy.stats`
(95a5d6ea8b/scipy/stats/__init__.py (L665))
* `scipy.interpolate`
(95a5d6ea8b/scipy/interpolate/__init__.py (L221))
* `scipy.signal` (indirectly via
95a5d6ea8b/scipy/signal/_signal_api.py (L30))
* `numpy.testing`
(de784cd6ee/numpy/testing/__init__.py (L16-L18))
~There's this one category of **false positives** that have been added:~
Fixed the false positives by also ignoring `__all__` from a module that
uses unrecognized idioms.
<details><summary>Details about the false postivie:</summary>
<p>
The `scipy.stats` module has dynamic `__all__` and it imports a bunch of
symbols via star imports. Some of those modules have a mix of valid and
invalid `__all__` idioms. For example, in
95a5d6ea8b/scipy/stats/distributions.py (L18-L24),
2 out of 4 `__all__` idioms are invalid but currently `ty` recognizes
two of them and says that the module has a `__all__` with 5 values. This
leads to around **2055** newly added false positives of the form:
```
Type <module 'scipy.stats'> has no attribute ...
```
I think the fix here is to completely ignore `__all__`, not only if
there are invalid elements in it, but also if there are unrecognized
idioms used in the module.
</p>
</details>
## Test Plan
Add a bunch of test cases using the new `ty_extensions.dunder_all_names`
function to extract a module's `__all__` names.
Update various test cases to remove false positives around `*` imports
and re-export convention.
Add new test cases for named import behavior as `*` imports covers all
of it already (thanks Alex!).
## Summary
Fixes#17541
Before this change, in the case of overloaded functions,
`@dataclass_transform` was detected only when applied to the
implementation, not the overloads.
However, the spec also allows this decorator to be applied to any of the
overloads as well.
With this PR, we start handling `@dataclass_transform`s applied to
overloads.
## Test Plan
Fixed existing TODOs in the test suite.
## Summary
This is sort of an anticlimactic resolution to #17863, but now that we
understand what the root cause for the stack overflows was, I think it's
fine to enable running on this project. See the linked ticket for the
full analysis.
closes#17863
## Test Plan
Ran lots of times locally and never observed a crash at worker thread
stack sizes > 8 MiB.
We now track the variance of each typevar, and obey the `covariant` and
`contravariant` parameters to the legacy `TypeVar` constructor. We still
don't yet infer variance for PEP-695 typevars or for the
`infer_variance` legacy constructor parameter.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
A recursive protocol like the following would previously lead to stack
overflows when attempting to create the union type for the `P | None`
member, because `UnionBuilder` checks if element types are fully static,
and the fully-static check on `P` would in turn list all members and
check whether all of them were fully static, leading to a cycle.
```py
from __future__ import annotations
from typing import Protocol
class P(Protocol):
parent: P | None
```
Here, we make the fully-static check on protocols a salsa query and add
fixpoint iteration, starting with `true` as the initial value (assume
that the recursive protocol is fully-static). If the recursive protocol
has any non-fully-static members, we still return `false` when
re-executing the query (see newly added tests).
closes#17861
## Test Plan
Added regression test
## Summary
Resolves#15502.
`ty generate-shell-completion` now works in a similar manner to `ruff
generate-shell-completion`.
## Test Plan
Manually:
<details>
```shell
$ cargo run --package ty generate-shell-completion nushell
module completions {
# An extremely fast Python type checker.
export extern ty [
--help(-h) # Print help
--version(-V) # Print version
]
# ...
}
export use completions *
```
</details>
@AlexWaygood discovered that even though we've been propagating
specializations to _parent_ base classes correctly, we haven't been
passing them on to _grandparent_ base classes:
https://github.com/astral-sh/ruff/pull/17832#issuecomment-2854360969
```py
class Bar[T]:
x: T
class Baz[T](Bar[T]): ...
class Spam[T](Baz[T]): ...
reveal_type(Spam[int]().x) # revealed: `T`, but should be `int`
```
This PR updates the MRO machinery to apply the current specialization
when starting to iterate the MRO of each base class.
## Summary
This PR partially addresses #16418 via the following:
- `LinterSettings::unresolved_python_version` is now a `TargetVersion`,
which is a thin wrapper around an `Option<PythonVersion>`
- `Checker::target_version` now calls `TargetVersion::linter_version`
internally, which in turn uses `unwrap_or_default` to preserve the
current default behavior
- Calls to the parser now call `TargetVersion::parser_version`, which
calls `unwrap_or_else(PythonVersion::latest)`
- The `Checker`'s implementation of
`SemanticSyntaxContext::python_version` also uses
`TargetVersion::parser_version` to use `PythonVersion::latest` for
semantic errors
In short, all lint rule behavior should be unchanged, but we default to
the latest Python version for the new syntax errors, which should
minimize confusing version-related syntax errors for users without a
version configured.
## Test Plan
Existing tests, which showed no changes (except for printing default
settings).
## Summary
Introducing a new rule based on discussions in #15732 and #15729 that
checks for unnecessary in with empty collections.
I called it in_empty_collection and gave the rule number RUF060.
Rule is in preview group.
e.g.,
```
❯ uv run -q -- ty -V
ty 0.0.0-alpha.4 (08881edba 2025-05-05)
❯ uv run -q -- ty --version
ty 0.0.0-alpha.4 (08881edba 2025-05-05)
```
Previously, this just displayed `ty 0.0.0` because it didn't use our
custom version implementation. We no longer have a short version —
matching the interface in uv. We could add a variant for it, if it seems
important to people. However, I think we found it more confusing than
not over there and didn't get any complaints about the change.
Closes https://github.com/astral-sh/ty/issues/54
Extends https://github.com/astral-sh/ruff/pull/17866, using
`dist-workspace.toml` as a source of truth for versions to enable
version retrieval in distributions that are not Git repositories (i.e.,
Python source distributions and source tarballs consumed by Linux
distros).
I retain the Git tag lookup from
https://github.com/astral-sh/ruff/pull/17866 as a fallback — it seems
harmless, but we could drop it to simplify things here.
I confirmed this works from the repository as well as Python source and
binary distributions:
```
❯ uv run --refresh-package ty --reinstall-package ty -q -- ty version
ty 0.0.1-alpha.1+5 (2eadc9e61 2025-05-05)
❯ uv build
...
❯ uvx --from ty@dist/ty-0.0.0a1.tar.gz --no-cache -q -- ty version
ty 0.0.1-alpha.1
❯ uvx --from ty@dist/ty-0.0.0a1-py3-none-macosx_11_0_arm64.whl -q -- ty version
ty 0.0.1-alpha.1
```
Requires https://github.com/astral-sh/ty/pull/36
cc @Gankra and @MichaReiser for review.
Currently, `ty version` pulls its information from the Ruff repository —
but we want this to pull from the repository in the directory _above_
when Ruff is a submodule.
I tested this in the `ty` repository after tagging an arbitrary commit:
```
❯ uv run --refresh-package ty --reinstall-package ty ty version
Built ty @ file:///Users/zb/workspace/ty
Uninstalled 1 package in 2ms
Installed 1 package in 1ms
ty 0.0.0+3 (34253b1d4 2025-05-05)
```
We also use the last Git tag as the source of truth for the version,
instead of the crate version. However, we'll need a way to set the
version for releases still, as the tag is published _after_ the build.
We can either tag early (without pushing the tag to the remote), or add
another environment variable. (**Note, this approach is changed in a
follow-up. See https://github.com/astral-sh/ruff/pull/17868**)
From this repository, the version will be `unknown`:
```
❯ cargo run -q --bin ty -- version
ty unknown
```
We could add special handling like... `ty unknown (ruff@...)` but I see
that as a secondary goal.
Closes https://github.com/astral-sh/ty/issues/5
The reviewer situation in this repository is unhinged, cc @Gankra and
@MichaReiser for review.
## Summary
This fixes some false positives that showed up in the primer diff for
https://github.com/astral-sh/ruff/pull/17832
## Test Plan
new mdtests added that fail with false-positive diagnostics on `main`
## Summary
This PR fixes#17595.
## Test Plan
New test cases are added to `mdtest/narrow/conditionals/nested.md`.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
If a typevar is declared as having a default, we shouldn't require a
type to be specified for that typevar when explicitly specializing a
generic class:
```py
class WithDefault[T, U = int]: ...
reveal_type(WithDefault[str]()) # revealed: WithDefault[str, int]
```
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Fixes
https://github.com/astral-sh/ruff/pull/17832#issuecomment-2851224968. We
had a comment that we did not need to apply specializations to generic
aliases, or to the bound `self` of a bound method, because they were
already specialized. But they might be specialized with a type variable,
which _does_ need to be specialized, in the case of a "multi-step"
specialization, such as:
```py
class LinkedList[T]: ...
class C[U]:
def method(self) -> LinkedList[U]:
return LinkedList[U]()
```
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
closes#17472
This is obviously just a band-aid solution to this problem (in that you
can always make your [pathological
inputs](28994edd82/sympy/polys/numberfields/resolvent_lookup.py)
bigger and it will still crash), but I think this is not an unreasonable
change — even if we add more sophisticated solutions later. I tried
using `stacker` as suggested by @MichaReiser, and it works. But it's
unclear where exactly would be the right place to put it, and even for
the `sympy` problem, we would need to add it both in the semantic index
builder AST traversal and in type inference. Increasing the default
stack size for worker threads, as proposed here, doesn't solve the
underlying problem (that there is a hard limit), but it is more
universal in the sense that it is not specific to large binary-operator
expression chains.
To determine a reasonable stack size, I created files that look like
*right associative*:
```py
from typing import reveal_type
total = (1 + (1 + (1 + (1 + (… + 1)))))
reveal_type(total)
```
*left associative*
```py
from typing import reveal_type
total = 1 + 1 + 1 + 1 + … + 1
reveal_type(total)
```
with a variable amount of operands (`N`). I then chose the stack size
large enough to still be able to handle cases that existing type
checkers can not:
```
right
N = 20: mypy takes ~ 1min
N = 350: pyright crashes with a stack overflow (mypy fails with "too many nested parentheses")
N = 800: ty(main) infers Literal[800] instantly
N = 1000: ty(main) crashes with "thread '<unknown>' has overflowed its stack"
N = 7000: ty(this branch) infers Literal[7000] instantly
N = 8000+: ty(this branch) crashes
left
N = 300: pyright emits "Maximum parse depth exceeded; break expression into smaller sub-expressions"
total is inferred as Unknown
N = 5500: mypy crashes with "INTERNAL ERROR"
N = 2500: ty(main) infers Literal[2500] instantly
N = 3000: ty(main) crashes with "thread '<unknown>' has overflowed its stack"
N = 22000: ty(this branch) infers Literal[22000] instantly
N = 23000+: ty(this branch) crashes
```
## Test Plan
New regression test.
This fixes cycle panics in several ecosystem projects (moved to
`good.txt` in a following PR
https://github.com/astral-sh/ruff/pull/17834 because our mypy-primer job
doesn't handle it well if we move projects to `good.txt` in the same PR
that fixes `ty` to handle them), as well as in the minimal case in the
added mdtest. It also fixes a number of panicking fuzzer seeds. It
doesn't appear to cause any regression in any ecosystem project or any
fuzzer seed.
The PR add the fix safety section for rule `RUF013`
(https://github.com/astral-sh/ruff/issues/15584 )
The fix was introduced here #4831
The rule as a lot of False Negative (as it is explained in the docs of
the rule).
The main reason because the fix is unsafe is that it could change code
generation tools behaviour, as in the example here:
```python
def generate_api_docs(func):
hints = get_type_hints(func)
for param, hint in hints.items():
if is_optional_type(hint):
print(f"Parameter '{param}' is optional")
else:
print(f"Parameter '{param}' is required")
# Before fix
def create_user(name: str, roles: list[str] = None):
pass
# After fix
def create_user(name: str, roles: Optional[list[str]] = None):
pass
# Generated docs would change from "roles is required" to "roles is optional"
```
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Re: #17526
## Summary
Add test fixtures for `AwaitOutsideAsync` and
`AsyncComprehensionOutsideAsyncFunction` errors.
<!-- What's the purpose of the change? What does it do, and why? -->
## Test Plan
This is a test.
<!-- How was it tested? -->
Re: #17526
## Summary
Add integration tests for Python Semantic Syntax for
`InvalidStarExpression`, `DuplicateMatchKey`, and
`DuplicateMatchClassAttribute`.
## Note
- Red knot integration tests for `DuplicateMatchKey` exist already in
line 89-101.
<!-- What's the purpose of the change? What does it do, and why? -->
## Test Plan
This is a test.
<!-- How was it tested? -->
When attempting to determine whether `import foo.bar.baz` is a known
first-party import relative to [user-provided source
paths](https://docs.astral.sh/ruff/settings/#src), when `preview` is
enabled we now check that `SRC/foo/bar/baz` is a directory or
`SRC/foo/bar/baz.py` or `SRC/foo/bar/baz.pyi` exist.
Previously, we just checked the analogous thing for `SRC/foo`, but this
can be misleading in situations with disjoint namespace packages that
share a common base name (e.g. we may be working inside the namespace
package `foo.buzz` and importing `foo.bar` from elsewhere).
Supersedes #12987Closes#12984
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## Summary
Fixes#17798
<!-- What's the purpose of the change? What does it do, and why? -->
## Test Plan
Snapshot tests
<!-- How was it tested? -->
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Skip attribute check in try catch block (`AIR301`)
## Test Plan
<!-- How was it tested? -->
update
`crates/ruff_linter/resources/test/fixtures/airflow/AIR301_names_try.py`
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Remove `airflow.utils.dag_parsing_context.get_parsing_context` from
AIR301 as it has been moved to AIR311
## Test Plan
<!-- How was it tested? -->
the test fixture was updated in the previous PR
## Summary
When entering an `infer_expression_types` cycle from
`TypeInferenceBuilder::infer_standalone_expression`, we might get back a
`TypeInference::cycle_fallback(…)` that doesn't actually contain any new
types, but instead it contains a `cycle_fallback_type` which is set to
`Some(Type::Never)`. When calling `self.extend(…)`, we therefore don't
really pull in a type for the expression we're interested in. This
caused us to panic if we tried to call `self.expression_type(…)` after
`self.extend(…)`.
The proposed fix here is to retrieve that type from the nested
`TypeInferenceBuilder` directly, which will correctly fall back to
`cycle_fallback_type`.
## Details
I minimized the second example from #17792 a bit further and used this
example for debugging:
```py
from __future__ import annotations
class C: ...
def f(arg: C):
pass
x, _ = f(1)
assert x
```
This is self-referential because when we check the assignment statement
`x, _ = f(1)`, we need to look up the signature of `f`. Since evaluation
of annotations is deferred, we look up the public type of `C` for the
`arg` parameter. The public use of `C` is visibility-constraint by "`x`"
via the `assert` statement. While evaluating this constraint, we need to
look up the type of `x`, which in turn leads us back to the `x, _ =
f(1)` definition.
The reason why this only showed up in the relatively peculiar case with
unpack assignments is the code here:
78b4c3ccf1/crates/ty_python_semantic/src/types/infer.rs (L2709-L2718)
For a non-unpack assignment like `x = f(1)`, we would not try to infer
the right-hand side eagerly. Instead, we would enter a
`infer_definition_types` cycle that handles the situation correctly. For
unpack assignments, however, we try to infer the type of `value`
(`f(1)`) and therefore enter the cycle via `standalone_expression_type
=> infer_expression_type`.
closes#17792
## Test Plan
* New regression test
* Made sure that we can now run successfully on scipy => see #17850
This PR updates the semantic model for Python 3.14 by essentially
equating "run using Python 3.14" with "uses `from __future__ import
annotations`".
While this is not technically correct under the hood, it appears to be
correct for the purposes of our semantic model. That is: from the point
of view of deciding when to parse, bind, etc. annotations, these two
contexts behave the same. More generally these contexts behave the same
unless you are performing some kind of introspection like the following:
Without future import:
```pycon
>>> from annotationlib import get_annotations,Format
>>> def foo()->Bar:...
...
>>> get_annotations(foo,format=Format.FORWARDREF)
{'return': ForwardRef('Bar')}
>>> get_annotations(foo,format=Format.STRING)
{'return': 'Bar'}
>>> get_annotations(foo,format=Format.VALUE)
Traceback (most recent call last):
[...]
NameError: name 'Bar' is not defined
>>> get_annotations(foo)
Traceback (most recent call last):
[...]
NameError: name 'Bar' is not defined
```
With future import:
```
>>> from __future__ import annotations
>>> from annotationlib import get_annotations,Format
>>> def foo()->Bar:...
...
>>> get_annotations(foo,format=Format.FORWARDREF)
{'return': 'Bar'}
>>> get_annotations(foo,format=Format.STRING)
{'return': 'Bar'}
>>> get_annotations(foo,format=Format.VALUE)
{'return': 'Bar'}
>>> get_annotations(foo)
{'return': 'Bar'}
```
(Note: the result of the last call to `get_annotations` in these
examples relies on the fact that, as of this writing, the default value
for `format` is `Format.VALUE`).
If one day we support lint rules targeting code that introspects using
the new `annotationlib`, then it is possible we will need to revisit our
approximation.
Closes#15100