Fixes#18069
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## Summary
This PR addresses a bug in the `flake8-simplify` rule `SIM905`
(split-static-string) where `str.split(maxsplit=0)` and
`str.rsplit(maxsplit=0)` produced incorrect results for empty strings or
strings starting/ending with whitespace. The fix ensures that the
linting rule's suggested replacements now align with Python's native
behavior for these specific `maxsplit=0` scenarios.
## Test Plan
1. Added new test cases to the existing
`crates/ruff_linter/resources/test/fixtures/flake8_simplify/SIM905.py`
fixture to cover the scenarios described in issue #18069.
2. Ran `cargo test -p ruff_linter`.
3. Verified and accepted the updated snapshots for `SIM905.py` using
`cargo insta review`. The new snapshots confirm the corrected behavior
for `maxsplit=0`.
The diagnostic now includes a pointer to the implementation definition
along with each possible overload.
This doesn't include information about *why* each overload failed. But
given the emphasis on concise output (since there can be *many*
unmatched overloads), it's not totally clear how to include that
additional information.
Fixes#274
These are, after all, specific to function types. The methods on `Type`
are more like conveniences that return something when the type *happens*
to be a function. But defining them on `FunctionType` itself makes it
easy to call them when you have a `FunctionType` instead of a `Type`.
I found the previous code somewhat harder to read. Namely, a `for`
loop was being used to encode "execute zero or one times, but not
more." Which is sometimes okay, but it seemed clearer to me to use
more explicit case analysis here.
This should have no behavioral changes.
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Similiar to https://github.com/astral-sh/ruff/pull/17941.
`Replacement::Name` was designed for linting only. Now, we also want to
fix the user code. It would be easier to replace it with a better
AutoImport struct whenever possible.
On the other hand, `AIR301` and `AIR311` contain attribute changes that
can still use a struct like `Replacement::Name`. To reduce the
confusion, I also updated it as `Replacement::AttrName`
Some of the original `Replacement::Name` has been replaced as
`Replacement::Message` as they're not directly mapping and the message
has now been moved to `help`
## Test Plan
<!-- How was it tested? -->
The test fixtures have been updated
The PR add the `fix safety` section for rule `RUF007` (#15584 )
It seems that the fix was always marked as unsafe #14401
## Unsafety example
This first example is a little extreme. In fact, the class `Foo`
overrides the `__getitem__` method but in a very special, way. The
difference lies in the fact that `zip(letters, letters[1:])` call the
slice `letters[1:]` which is behaving weird in this case, while
`itertools.pairwise(letters)` call just `__getitem__(0), __getitem__(1),
...` and so on.
Note that the diagnostic is emitted: [playground](https://play.ruff.rs)
I don't know if we want to mention this problem, as there is a subtile
bug in the python implementation of `Foo` which make the rule unsafe.
```python
from dataclasses import dataclass
import itertools
@dataclass
class Foo:
letters: str
def __getitem__(self, index):
return self.letters[index] + "_foo"
letters = Foo("ABCD")
zip_ = zip(letters, letters[1:])
for a, b in zip_:
print(a, b) # A_foo B, B_foo C, C_foo D, D_foo _
pair = itertools.pairwise(letters)
for a, b in pair:
print(a, b) # A_foo B_foo, B_foo C_foo, C_foo D_foo
```
This other example is much probable.
here, `itertools.pairwise` was shadowed by a costume function
[(playground)](https://play.ruff.rs)
```python
from dataclasses import dataclass
from itertools import pairwise
def pairwise(a):
return []
letters = "ABCD"
zip_ = zip(letters, letters[1:])
print([(a, b) for a, b in zip_]) # [('A', 'B'), ('B', 'C'), ('C', 'D')]
pair = pairwise(letters)
print(pair) # []
```
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## Summary
Fixes#17599.
## Test Plan
Snapshot tests.
---------
Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
## Summary
Dunder methods are never looked up on instances. We do this implicitly
in `try_call_dunder`, but the corresponding flag was missing in the
instance-construction code where we use `member_lookup_with_policy`
directly.
fixes https://github.com/astral-sh/ty/issues/322
## Test Plan
Added regression test.
## Summary
This PR adds cycle handling for `infer_unpack_types` based on the
analysis in astral-sh/ty#364.
Fixes: astral-sh/ty#364
## Test Plan
Add a cycle handling test for unpacking in `cycle.md`
## 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