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
## Summary
Currently red-knot does not understand `Foo` and `Bar` here as being
equivalent:
```py
from typing import Protocol
class A: ...
class B: ...
class C: ...
class Foo(Protocol):
x: A | B | C
class Bar(Protocol):
x: B | A | C
```
Nor does it understand `A | B | Foo` as being equivalent to `Bar | B |
A`. This PR fixes that.
## Test Plan
new mdtest assertions added that fail on `main`
## Summary
Currently this assertion fails on `main`, because we do not synthesize a
`__call__` attribute for Callable types:
```py
from typing import Protocol, Callable
from knot_extensions import static_assert, is_assignable_to
class Foo(Protocol):
def __call__(self, x: int, /) -> str: ...
static_assert(is_assignable_to(Callable[[int], str], Foo))
```
This PR fixes that.
See previous discussion about this in
https://github.com/astral-sh/ruff/pull/16493#discussion_r1985098508 and
https://github.com/astral-sh/ruff/pull/17682#issuecomment-2839527750
## Test Plan
Existing mdtests updated; a couple of new ones added.
This adds support for legacy generic classes, which use a
`typing.Generic` base class, or which inherit from another generic class
that has been specialized with legacy typevars.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Quick follow-on to #17788. If there is no bound `self` parameter, we can
reuse the existing `CallArgument{,Type}s`, and we can use a straight
`Vec` instead of a `VecDeque`.
## Summary
Remove mutability in parameter types for a few functions such as
`with_self` and `try_call`. I tried the `Rc`-approach with cheap cloning
[suggest
here](https://github.com/astral-sh/ruff/pull/17733#discussion_r2068722860)
first, but it turns out we need a whole stack of prepended arguments
(there can be [both `self` *and*
`cls`](3cf44e401a/crates/red_knot_python_semantic/resources/mdtest/call/constructor.md (L113))),
and we would need the same construct not just for `CallArguments` but
also for `CallArgumentTypes`. At that point we're cloning `VecDeque`s
anyway, so the overhead of cloning the whole `VecDeque` with all
arguments didn't seem to justify the additional code complexity.
## Benchmarks
Benchmarks on tomllib, black, jinja, isort seem neutral.
## Summary
Add the ability to detect instance attribute assignments in class
methods that are generic.
This does not address the code duplication mentioned in #16928. I can
open a ticket for this after this has been merged.
closes#16928
## Test Plan
Added regression test.
