## Summary
Extracts the vendored typeshed stubs lazily and caches them on the local
filesystem to support go-to in the LSP.
Resolves https://github.com/astral-sh/ty/issues/77.
## Summary
This PR makes the necessary changes to the server that it can request
configurations from the client using the `configuration` request.
This PR doesn't make use of the request yet. It only sets up the
foundation (mainly the coordination between client and server)
so that future PRs could pull specific settings.
I plan to use this for pulling the Python environment from the Python
extension.
Deno does something very similar to this.
## Test Plan
Tested that diagnostics are still shown.
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Part of #18972
This PR makes [duplicate-literal-member
(PYI062)](https://docs.astral.sh/ruff/rules/duplicate-literal-member/#duplicate-literal-member-pyi062)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/6b00b41c-c1c5-4421-873d-fc2a143e7337)
```py
foo: Literal["a", "b", "a"]
```
[New example](https://play.ruff.rs/1aea839b-9ae8-4848-bb83-2637e1a68ce4)
```py
from typing import Literal
foo: Literal["a", "b", "a"]
```
Imports were also added to the "use instead" section.
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
Follow-up to https://github.com/astral-sh/ruff/pull/19083, also log the
target names like `ty_python_semantic::module_resolver::resolver` in
`2025-07-02 10:12:20.188697000 DEBUG
ty_python_semantic::module_resolver::resolver: Adding first-party search
path '/Users/dhruv/playground/ty_server'` at trace level.
## Summary
I hoped this might fix the latest stack overflows on
https://github.com/astral-sh/ruff/pull/18659... it doesn't look like it
does, but these changes seem like they're probably correct anyway...?
## Test Plan
<!-- How was it tested? -->
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
This PR fixes#19047 / the [isinstance-type-none
(FURB168)](https://docs.astral.sh/ruff/rules/isinstance-type-none/#isinstance-type-none-furb168)
tuple false positive by adding a check if the tuple is empty to the
code. I also noticed there was another false positive with the other
tuple check in the same function, so I fixed it the same way.
`Union[()]` is invalid at runtime with `TypeError: Cannot take a Union
of no types.`, but it is accepted by `basedpyright`
[playground](https://basedpyright.com/?pythonVersion=3.8&typeCheckingMode=all&code=GYJw9gtgBALgngBwJYDsDmUkQWEMoCqKSYKAsAFAgCmAbtQIYA2A%2BvAtQBREkoDanAJQBdQUA)
and is equivalent to `Never`, so I fixed it anyways. I'm getting on a
side tangent here, but it looks like MyPy doesn't accept it, and ty
[playground](https://play.ty.dev/c2c468b6-38e4-4dd9-a9fa-0276e843e395)
gives `@Todo`.
## Test Plan
<!-- How was it tested? -->
Added two test cases for the two false positives.
[playground](https://play.ruff.rs/a53afc21-9a1d-4b9b-9346-abfbeabeb449)
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Part of #18972
This PR makes [datetime-min-max
(DTZ901)](https://docs.astral.sh/ruff/rules/datetime-min-max/#datetime-min-max-dtz901)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/c1202727-1a18-4d3f-92a4-334ede07ed3e)
```py
datetime.max
```
[New example](https://play.ruff.rs/af2c76aa-9beb-46bc-8e27-faf53ecdbe8c)
```py
import datetime
datetime.datetime.max
```
I also added imports to the problem demonstration and use instead.
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
## Summary
Remove a hack in control flow modeling that was treating `return`
statements at the end of function bodies in a special way (basically
considering the state *just before* the `return` statement as the
end-of-scope state). This is not needed anymore now that #18750 has been
merged.
In order to make this work, we now use *all reachable bindings* for
purposes of finding implicit instance attribute assignments as well as
for deferred lookups of symbols. Both would otherwise be affected by
this change:
```py
def C:
def f(self):
self.x = 1 # a reachable binding that is not visible at the end of the scope
return
```
```py
def f():
class X: ... # a reachable binding that is not visible at the end of the scope
x: "X" = X() # deferred use of `X`
return
```
Implicit instance attributes also required another change. We previously
kept track of possibly-unbound instance attributes in some cases, but we
now give up on that completely and always consider *implicit* instance
attributes to be bound if we see a reachable binding in a reachable
method. The previous behavior was somewhat inconsistent anyway because
we also do not consider attributes possibly-unbound in other scenarios:
we do not (and can not) keep track of whether or not methods are called
that define these attributes.
closes https://github.com/astral-sh/ty/issues/711
## Ecosystem analysis
I think this looks very positive!
* We see an unsurprising drop in `possibly-unbound-attribute`
diagnostics (599), mostly for classes that define attributes in `try …
except` blocks, `for` loops, or `if … else: raise …` constructs. There
might obviously also be true positives that got removed, but the vast
majority should be false positives.
* There is also a drop in `possibly-unresolved-reference` /
`unresolved-reference` diagnostics (279+13) from the change to deferred
lookups.
* Some `invalid-type-form` false positives got resolved (13), because we
can now properly look up the names in the annotations.
* There are some new *true* positives in `attrs`, since we understand
the `Attribute` annotation that was previously inferred as `Unknown`
because of a re-assignment after the class definition.
## Test Plan
The existing attributes.md test suite has sufficient coverage here.
## Summary
Temporarily modify `UseDefMapBuilder::reachability` for star imports in
order for new definitions to pick up the right reachability. This was
already working for `UseDefMapBuilder::place_states`, but not for
`UseDefMapBuilder::reachable_definitions`.
closes https://github.com/astral-sh/ty/issues/728
## Test Plan
Regression test
## Summary
Evaluate `TYPE_CHECKING` to `ALWAYS_TRUE` and `not TYPE_CHECKING` to
`ALWAYS_FALSE` during semantic index building. This is a follow-up to
https://github.com/astral-sh/ruff/pull/18998 and is in principle just a
performance optimization. We see some (favorable) ecosystem changes
because we can eliminate definitely-unreachable branches early now and
retain narrowing constraints without solving
https://github.com/astral-sh/ty/issues/690 first.
Gates all uses of `get-size2` behind the feature `get-size` in the crate
`ruff_python_ast`. Also requires that `ruff_text_size` is pulled in with
the feature `get-size` enabled if we enable the same-named feature for
`ruff_python_ast`.
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## Summary
Make `UP045` ignore `Optional[NamedTuple]` as `NamedTuple` is a function
(not a proper type). Rewriting it to `NamedTuple | None` breaks at
runtime. While type checkers currently accept `NamedTuple` as a type,
they arguably shouldn't. Therefore, we outright ignore it and don't
touch or lint on it.
For a more detailed discussion, see the linked issue.
## Test Plan
Added examples to the existing tests.
## Related Issues
Fixes: https://github.com/astral-sh/ruff/issues/18619
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Part of #18972
This PR makes [call-date-today
(DTZ011)](https://docs.astral.sh/ruff/rules/call-date-today/#call-date-today-dtz011)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/b42d6aef-7777-4b3b-9f96-19132000b765)
```py
import datetime
datetime.datetime.today()
```
[New example](https://play.ruff.rs/8577c3c1-cfa8-425b-b1e1-4c53b2a48375)
```py
import datetime
datetime.date.today()
```
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Part of #18972
This PR makes [no-explicit-stacklevel
(B028)](https://docs.astral.sh/ruff/rules/no-explicit-stacklevel/#no-explicit-stacklevel-b028)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/1ee80aec-2d6e-4a3f-8e98-da82b6a9f544)
```py
warnings.warn("This is a warning")
```
[New example](https://play.ruff.rs/343593aa-38a0-4d76-a32b-5abd0a4306cc)
```py
import warnings
warnings.warn("This is a warning")
```
Imports were also added to the "use instead" section
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Part of #18972
This PR makes [batched-without-explicit-strict
(B911)](https://docs.astral.sh/ruff/rules/batched-without-explicit-strict/#batched-without-explicit-strict-b911)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/a897d96b-0749-4291-8a62-dfd4caf290a0)
```py
itertools.batched(iterable, n)
```
[New example](https://play.ruff.rs/1c1e0ab7-014c-4dc2-abed-c2cb6cd01f70)
```py
import itertools
itertools.batched(iterable, n)
```
Imports were also added to the "use instead" sections
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
## Summary
This just replaces one temporary solution to recursive protocols (the
`SelfReference` mechanism) with another one (track seen types when
recursively descending in `normalize` and replace recursive references
with `Any`). But this temporary solution can handle mutually-recursive
types, not just self-referential ones, and it's sufficient for the
primer ecosystem and some other projects we are testing on to no longer
stack overflow.
The follow-up here will be to properly handle these self-references
instead of replacing them with `Any`.
We will also eventually need cycle detection on more recursive-descent
type transformations and tests.
## Test Plan
Existing tests (including recursive-protocol tests) and primer.
Added mdtest for mutually-recursive protocols that stack-overflowed
before this PR.
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## Summary
This PR fixes rule C420's fix. The fix replaces `{...}` with
`dict....(...)`. Therefore, if there is any identifier or such right
before the fix, the fix will fuse that previous token with `dict...`.
The example in the issue is
```python
0 or{x: None for x in "x"}
# gets "fixed" to
0 ordict.fromkeys(iterable)
```
## Related Issues
Fixes: https://github.com/astral-sh/ruff/issues/18599
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Fixes#18908
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## Summary
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Part of #18972
This PR makes [airflow3-moved-to-provider
(AIR302)](https://docs.astral.sh/ruff/rules/airflow3-moved-to-provider/#airflow3-moved-to-provider-air302)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/1026c008-57bc-4330-93b9-141444f2a611)
```py
from airflow.auth.managers.fab.fab_auth_manage import FabAuthManager
```
[New example](https://play.ruff.rs/b690e809-a81d-4265-9fde-1494caa0b7fd)
```py
from airflow.auth.managers.fab.fab_auth_manager import FabAuthManager
fab_auth_manager_app = FabAuthManager().get_fastapi_app()
```
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
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## Summary
Mark `UP008`'s fix safe if it won't delete comments.
## Relevant Issues
Fixes: https://github.com/astral-sh/ruff/issues/18533
---------
Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
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## Summary
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Part of #18972
This PR makes [flask-debug-true
(S201)](https://docs.astral.sh/ruff/rules/flask-debug-true/#flask-debug-true-s201)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/d5e1a013-1107-4223-9094-0e8393ad3c64)
```py
import flask
app = Flask()
app.run(debug=True)
```
[New example](https://play.ruff.rs/c4aebd2c-0448-4471-8bad-3e38ace68367)
```py
from flask import Flask
app = Flask()
app.run(debug=True)
```
Imports were also added to the `Use instead:` section to make it valid
code out-of-the-box.
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
## Summary
Simplifies literal `True` and `False` conditions to `ALWAYS_TRUE` /
`ALWAYS_FALSE` during semantic index building. This allows us to eagerly
evaluate more constraints, which should help with performance (looks
like there is a tiny 1% improvement in instrumented benchmarks), but
also allows us to eliminate definitely-unreachable branches in
control-flow merging. This can lead to better type inference in some
cases because it allows us to retain narrowing constraints without
solving https://github.com/astral-sh/ty/issues/690 first:
```py
def _(c: int | None):
if c is None:
assert False
reveal_type(c) # int, previously: int | None
```
closes https://github.com/astral-sh/ty/issues/713
## Test Plan
* Regression test for https://github.com/astral-sh/ty/issues/713
* Made sure that all ecosystem diffs trace back to removed false
positives
## Summary
This PR adds diagnostic for invalid binary operators in type
expressions. It should close https://github.com/astral-sh/ty/issues/706
if merged.
Please feel free to suggest better wordings for the diagnostic message.
## Test Plan
I modified `mdtest/annotations/invalid.md` and added a test for each
binary operator, and fixed tests that was broken by the new diagnostic.
## Summary
Print the [new salsa memory usage
dumps](https://github.com/astral-sh/ruff/pull/18928) in mypy primer CI
runs to help us catch memory regressions. The numbers are rounded to the
nearest power of 1.1 (about a 5% threshold between buckets) to avoid overly sensitive diffs.
