## Summary
Add support for decorators on function as well as support
for properties by adding special handling for `@property` and `@<name of
property>.setter`/`.getter` decorators.
closes https://github.com/astral-sh/ruff/issues/16987
## Ecosystem results
- ✔️ A lot of false positives are fixed by our new
understanding of properties
- 🔴 A bunch of new false positives (typically
`possibly-unbound-attribute` or `invalid-argument-type`) occur because
we currently do not perform type narrowing on attributes. And with the
new understanding of properties, this becomes even more relevant. In
many cases, the narrowing occurs through an assertion, so this is also
something that we need to implement to get rid of these false positives.
- 🔴 A few new false positives occur because we do not
understand generics, and therefore some calls to custom setters fail.
- 🔴 Similarly, some false positives occur because we do not
understand protocols yet.
- ✔️ Seems like a true positive to me. [The
setter](e624d8edfa/src/packaging/specifiers.py (L752-L754))
only accepts `bools`, but `None` is assigned in [this
line](e624d8edfa/tests/test_specifiers.py (L688)).
```
+ error[lint:invalid-assignment]
/tmp/mypy_primer/projects/packaging/tests/test_specifiers.py:688:9:
Invalid assignment to data descriptor attribute `prereleases` on type
`SpecifierSet` with custom `__set__` method
```
- ✔️ This is arguable also a true positive. The setter
[here](0c6c75644f/rich/table.py (L359-L363))
returns `Table`, but typeshed wants [setters to return
`None`](bf8d2a9912/stdlib/builtins.pyi (L1298)).
```
+ error[lint:invalid-argument-type]
/tmp/mypy_primer/projects/rich/rich/table.py:359:5: Object of type
`Literal[padding]` cannot be assigned to parameter 2 (`fset`) of bound
method `setter`; expected type `(Any, Any, /) -> None`
```
## Follow ups
- Fix the `@no_type_check` regression
- Implement class decorators
## Test Plan
New Markdown test suites for decorators and properties.
## Summary
This PR closes#16248.
If the return type of the function isn't assignable to the one
specified, an `invalid-return-type` error occurs.
I thought it would be better to report this as a different kind of error
than the `invalid-assignment` error, so I defined this as a new error.
## Test Plan
All type inconsistencies in the test cases have been replaced with
appropriate ones.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
Add support for `@classmethod`s.
```py
class C:
@classmethod
def f(cls, x: int) -> str:
return "a"
reveal_type(C.f(1)) # revealed: str
```
## Test Plan
New Markdown tests
## Summary
Another small PR to focus #15674 solely on the relevant changes. This
makes our Markdown tests less dependent on precise types of public
symbols, without actually changing anything semantically in these tests.
Best reviewed using ignore-whitespace-mode.
## Test Plan
Tested these changes on `main` and on the branch from #15674.
## Summary
Adds meta information to `Type::Todo`, allowing developers to easily
trace back the origin of a particular `@Todo` type they encounter.
Instead of `Type::Todo`, we now write either `type_todo!()` which
creates a `@Todo[path/to/source.rs:123]` type with file and line
information, or using `type_todo!("PEP 604 unions not supported")`,
which creates a variant with a custom message.
`Type::Todo` now contains a `TodoType` field. In release mode, this is
just a zero-sized struct, in order not to create any overhead. In debug
mode, this is an `enum` that contains the meta information.
`Type` implements `Copy`, which means that `TodoType` also needs to be
copyable. This limits the design space. We could intern `TodoType`, but
I discarded this option, as it would require us to have access to the
salsa DB everywhere we want to use `Type::Todo`. And it would have made
the macro invocations less ergonomic (requiring us to pass `db`).
So for now, the meta information is simply a `&'static str` / `u32` for
the file/line variant, or a `&'static str` for the custom message.
Anything involving a chain/backtrace of several `@Todo`s or similar is
therefore currently not implemented. Also because we currently don't see
any direct use cases for this, and because all of this will eventually
go away.
Note that the size of `Type` increases from 16 to 24 bytes, but only in
debug mode.
## Test Plan
- Observed the changes in Markdown tests.
- Added custom messages for all `Type::Todo`s that were revealed in the
tests
- Ran red knot in release and debug mode on the following Python file:
```py
def f(x: int) -> int:
reveal_type(x)
```
Prints `@Todo` in release mode and `@Todo(function parameter type)` in
debug mode.
## Summary
- Add a new `Type::SliceLiteral` variant
- Infer `SliceLiteral` types for slice expressions, such as
`<int-literal>:<int-literal>:<int-literal>`.
- Infer "sliced" literal types for subscript expressions using slices,
such as `<string-literal>[<slice-literal>]`.
- Infer types for expressions involving slices of tuples:
`<tuple>[<slice-literal>]`.
closes#13853
## Test Plan
- Unit tests for indexing/slicing utility functions
- Markdown-based tests for
- Subscript expressions `tuple[slice]`
- Subscript expressions `string_literal[slice]`
- Subscript expressions `bytes_literal[slice]`
## Summary
Add support for type narrowing in elif and else scopes as part of
#13694.
## Test Plan
- mdtest
- builder unit test for union negation.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Minor cleanup and consistent formatting of the Markdown-based tests.
- Removed lots of unnecessary `a`, `b`, `c`, … variables.
- Moved test assertions (`# revealed:` comments) closer to the tested
object.
- Always separate `# revealed` and `# error` comments from the code by
two spaces, according to the discussion
[here](https://github.com/astral-sh/ruff/pull/13746/files#r1799385758).
This trades readability for consistency in some cases.
- Fixed some headings
## Summary
Porting infer tests to new markdown tests framework.
Link to the corresponding issue: #13696
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
