Commit graph

50 commits

Author SHA1 Message Date
Carl Meyer
2a478ce1b2
[red-knot] simplify gradually-equivalent types out of unions and intersections (#17467)
## Summary

If two types are gradually-equivalent, that means they share the same
set of possible materializations. There's no need to keep two such types
in the same union or intersection; we should simplify them.

Fixes https://github.com/astral-sh/ruff/issues/17465

The one downside here is that now we will simplify e.g. `Unknown |
Todo(...)` to just `Unknown`, if `Unknown` was added to the union first.
This is correct from a type perspective (they are equivalent types), but
it can mean we lose visibility into part of the cause for the type
inferring as unknown. I think this is OK, but if we think it's important
to avoid this, I can add a special case to try to preserve `Todo` over
`Unknown`, if we see them both in the same union or intersection.

## Test Plan

Added and updated mdtests.
2025-04-18 15:08:57 -07:00
Douglas Creager
787bcd1c6a
[red-knot] Handle explicit class specialization in type expressions (#17434)
You can now use subscript expressions in a type expression to explicitly
specialize generic classes, just like you could already do in value
expressions.

This still does not implement bidirectional checking, so a type
annotation on an assignment does not influence how we infer a
specialization for a (not explicitly specialized) constructor call. You
might get an `invalid-assignment` error if (a) we cannot infer a class
specialization from the constructor call (in which case you end up e.g.
trying to assign `C[Unknown]` to `C[int]`) or if (b) we can infer a
specialization, but it doesn't match the annotation.

Closes https://github.com/astral-sh/ruff/issues/17432
2025-04-18 11:49:22 -04:00
Brent Westbrook
9c47b6dbb0
[red-knot] Detect version-related syntax errors (#16379)
## Summary
This PR extends version-related syntax error detection to red-knot. The
main changes here are:

1. Passing `ParseOptions` specifying a `PythonVersion` to parser calls
2. Adding a `python_version` method to the `Db` trait to make this
possible
3. Converting `UnsupportedSyntaxError`s to `Diagnostic`s
4. Updating existing mdtests  to avoid unrelated syntax errors

My initial draft of (1) and (2) in #16090 instead tried passing a
`PythonVersion` down to every parser call, but @MichaReiser suggested
the `Db` approach instead
[here](https://github.com/astral-sh/ruff/pull/16090#discussion_r1969198407),
and I think it turned out much nicer.

All of the new `python_version` methods look like this:

```rust
fn python_version(&self) -> ruff_python_ast::PythonVersion {
    Program::get(self).python_version(self)
}
```

with the exception of the `TestDb` in `ruff_db`, which hard-codes
`PythonVersion::latest()`.

## Test Plan

Existing mdtests, plus a new mdtest to see at least one of the new
diagnostics.
2025-04-17 14:00:30 -04:00
Douglas Creager
914095d08f
[red-knot] Super-basic generic inference at call sites (#17301)
This PR adds **_very_** basic inference of generic typevars at call
sites. It does not bring in a full unification algorithm, and there are
a few TODOs in the test suite that are not discharged by this. But it
handles a good number of useful cases! And the PR does not add anything
that would go away with a more sophisticated constraint solver.

In short, we just look for typevars in the formal parameters, and assume
that the inferred type of the corresponding argument is what that
typevar should map to. If a typevar appears more than once, we union
together the corresponding argument types.

Cases we are not yet handling:

- We are not widening literals.
- We are not recursing into parameters that are themselves generic
aliases.
- We are not being very clever with parameters that are union types.

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Co-authored-by: Carl Meyer <carl@astral.sh>
2025-04-16 15:07:36 -04:00
Carl Meyer
c7b5067ef8
[red-knot] set a size limit on unions of literals (#17419)
## Summary

Until we optimize our full union/intersection representation to
efficiently handle large numbers of same-kind literal types "as a
block", set a fairly low limit on the size of unions of literals.

We will want to increase this limit once we've made the broader
efficiency improvement (tracked in
https://github.com/astral-sh/ruff/issues/17420).

## Test Plan

`cargo bench --bench red_knot`
2025-04-16 14:23:11 +00:00
Mike Perlov
3b24fe5c07
[red-knot] improve function/bound method type display (#17294)
## Summary

* Partial #17238
* Flyby from discord discussion - `todo_type!` now statically checks for
no parens in the message to avoid issues between debug & release build
tests

## Test Plan

many mdtests are changing
2025-04-14 15:56:18 -07:00
David Peter
47956db567
[red-knot] Specialize str.startswith for string literals (#17351)
## Summary

Infer precise Boolean literal types for `str.startswith` calls where the
instance and the prefix are both string literals. This allows us to
understand `sys.platform.startswith(…)` branches.

## Test Plan

New Markdown tests
2025-04-11 16:26:45 +02:00
Andrew Gallant
7e2eb591bc red_knot_python_semantic: replace one use of "old" secondary diagnostic messages
This is the first use of the new `lint()` reporter.

I somewhat skipped a step here and also modified the actual diagnostic
message itself. The snapshots should tell the story.

We couldn't do this before because we had no way of differentiating
between "message for the diagnostic as a whole" and "message for a
specific code annotation." Now we can, so we can write more precise
messages based on the assumption that users are also seeing the code
snippet.

The downside here is that the actual message text can become quite vague
in the absence of the code snippet. This occurs, for example, with
concise diagnostic formatting. It's unclear if we should do anything
about it. I don't really see a way to make it better that doesn't
involve creating diagnostics with messages for each mode, which I think
would be a major PITA.

The upside is that this code gets a bit simpler, and we very
specifically avoid doing extra work if this specific lint is disabled.
2025-04-10 13:21:00 -04:00
Micha Reiser
8249a72412
[red-knot] Default python-platform to current platform (#17183)
## Summary

As discussed in https://github.com/astral-sh/ruff/issues/16983 and
"mitigate" said issue for the alpha.

This PR changes the default for `PythonPlatform` to be the current
platform rather than `all`.

I'm not sure if we should be as sophisticated as supporting `ios` and
`android` as defaults but it was easy...

## Test Plan

Updated Markdown tests.

---------

Co-authored-by: David Peter <mail@david-peter.de>
2025-04-09 12:05:18 +02:00
Mike Perlov
fab7d820bd
[red-knot] Add __init__ arguments check when doing try_call on a class literal (#16512)
## Summary

* Addresses #16511 for simple cases where only `__init__` method is
bound on class or doesn't exist at all.
* fixes a bug with argument counting in bound method diagnostics

Caveats:
* No handling of `__new__` or modified `__call__` on metaclass.
* This leads to a couple of false positive errors in tests

## Test Plan

- A couple new cases in mdtests
- cargo nextest run -p red_knot_python_semantic --no-fail-fast

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
Co-authored-by: David Peter <sharkdp@users.noreply.github.com>
2025-04-08 17:26:20 -04:00
David Peter
3f00010a7a
[red-knot] Three-argument type-calls take 'str' as the first argument (#17168)
## Summary

Similar to #17163, a minor fix in the signature of `type(…)`.

## Test Plan

New MD tests
2025-04-03 15:45:08 +02:00
David Peter
130339f3d8
[red-knot] Fix str(…) calls (#17163)
## Summary

The existing signature for `str` calls had various problems, one of
which I noticed while looking at some ecosystem projects (`scrapy`,
added as a project to mypy_primer in this PR).

## Test Plan

- New tests for `str(…)` calls.
- Observed reduction of false positives in ecosystem checks
2025-04-03 13:26:32 +02:00
David Peter
ae2cf91a36
[red-knot] Decorators and properties (#17017)
## 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.
2025-04-02 09:27:46 +02:00
Mike Perlov
5c1fab0661
Fix member lookup for unions & intersections ignoring policy (#17066)
## Summary

A quick fix for how union/intersection member search ins performed in
Knot.

## Test Plan

* Added a dunder method call test for Union, which exhibits the error
* Also added an intersection error, but it is not triggering currently
due to `call` logic not being fully implemented for intersections.

---------

Co-authored-by: David Peter <mail@david-peter.de>
2025-03-31 09:40:47 +02:00
Matthew Mckee
aae4d0f3eb
[red-knot] A FunctionType can be a subtype of Callable (but never the other way around) (#16970)
## Summary

Partially fixes #16953

## Test Plan

Update is_subtype_of.md

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2025-03-25 22:04:34 +00:00
Dhruv Manilawala
0360c6b219
[red-knot] Support calling a typing.Callable (#16888)
## Summary

Part of #15382, this PR adds support for calling a variable that's
annotated with `typing.Callable`.

## Test Plan

Add test cases in a new `call/annotation.md` file.
2025-03-23 02:39:33 +05:30
Douglas Creager
c03c28d199
[red-knot] Break up call binding into two phases (#16546)
This breaks up call binding into two phases:

- **_Matching parameters_** just looks at the names and kinds
(positional/keyword) of each formal and actual parameters, and matches
them up. Most of the current call binding errors happen during this
phase.

- Once we have matched up formal and actual parameters, we can **_infer
types_** of each actual parameter, and **_check_** that each one is
assignable to the corresponding formal parameter type.

As part of this, we add information to each formal parameter about
whether it is a type form or not. Once [PEP
747](https://peps.python.org/pep-0747/) is finalized, we can hook that
up to this internal type form representation. This replaces the
`ParameterExpectations` type, which did the same thing in a more ad hoc
way.

While we're here, we add a new fluent API for building `Parameter`s,
which makes our signature constructors a bit nicer to read. We also
eliminate a TODO where we were consuming types from the argument list
instead of the bound parameter list when evaluating our special-case
known functions.

Closes #15460

---------

Co-authored-by: Micha Reiser <micha@reiser.io>
2025-03-21 09:38:11 -04:00
Douglas Creager
23ccb52fa6
[red-knot] Handle unions of callables better (#16716)
This cleans up how we handle calling unions of types. #16568 adding a
three-level structure for callable signatures (`Signatures`,
`CallableSignature`, and `Signature`) to handle unions and overloads.

This PR updates the bindings side to mimic that structure. What used to
be called `CallOutcome` is now `Bindings`, and represents the result of
binding actual arguments against a possible union of callables.
`CallableBinding` is the result of binding a single, possibly
overloaded, callable type. `Binding` is the result of binding a single
overload.

While we're here, this also cleans up `CallError` greatly. It was
previously extracting error information from the bindings and storing it
in the error result. It is now a simple enum, carrying no data, that's
used as a status code to talk about whether the overall binding was
successful or not. We are now more consistent about walking the binding
itself to get detailed information about _how_ the binding was
unsucessful.

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Co-authored-by: Carl Meyer <carl@astral.sh>
2025-03-17 10:35:52 -04:00
Shunsuke Shibayama
78b5f0b165
[red-knot] detect invalid return type (#16540)
## 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>
2025-03-12 01:58:59 +00:00
Douglas Creager
e17cd350b6
[red-knot] Support multiple overloads when binding parameters at call sites (#16568)
This updates the `Signature` and `CallBinding` machinery to support
multiple overloads for a callable. This is currently only used for
`KnownFunction`s that we special-case in our type inference code. It
does **_not_** yet update the semantic index builder to handle
`@overload` decorators and construct a multi-signature `Overloads`
instance for real Python functions.

While I was here, I updated many of the `try_call` special cases to use
signatures (possibly overloaded ones now) and `bind_call` to check
parameter lists. We still need some of the mutator methods on
`OverloadBinding` for the special cases where we need to update return
types based on some Rust code.
2025-03-11 15:08:17 -04:00
David Peter
c60e8a037a
[red-knot] Add support for calling type[…] (#16597)
## Summary

This fixes the non-diagnostics part of #15948.

## Test Plan

New Markdown tests.

Negative diff on the ecosystem checks:

```diff
zipp (https://github.com/jaraco/zipp)
- error: lint:call-non-callable
-    --> /tmp/mypy_primer/projects/zipp/zipp/__init__.py:393:16
-     |
- 392 |     def _next(self, at):
- 393 |         return self.__class__(self.root, at)
-     |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Object of type `type[Unknown]` is not callable
- 394 |
- 395 |     def is_dir(self):
-     |
- 
- Found 9 diagnostics
+ Found 8 diagnostics

arrow (https://github.com/arrow-py/arrow)
+     |
+     |
+ warning: lint:unused-ignore-comment
+    --> /tmp/mypy_primer/projects/arrow/arrow/arrow.py:576:66
+ 574 |                 values.append(1)
+ 575 |
+ 576 |             floor = self.__class__(*values, tzinfo=self.tzinfo)  # type: ignore[misc]
+     |                                                                  -------------------- Unused blanket `type: ignore` directive
+ 577 |
+ 578 |             if frame_absolute == "week":
- error: lint:call-non-callable
-     --> /tmp/mypy_primer/projects/arrow/arrow/arrow.py:1080:16
-      |
- 1078 |           dt = self._datetime.astimezone(tz)
- 1079 |
- 1080 |           return self.__class__(
-      |  ________________^
- 1081 | |             dt.year,
- 1082 | |             dt.month,
- 1083 | |             dt.day,
- 1084 | |             dt.hour,
- 1085 | |             dt.minute,
- 1086 | |             dt.second,
- 1087 | |             dt.microsecond,
- 1088 | |             dt.tzinfo,
- 1089 | |             fold=getattr(dt, "fold", 0),
- 1090 | |         )
-      | |_________^ Object of type `type[Unknown]` is not callable
- 1091 |
- 1092 |       # string output and formatting
-      |

black (https://github.com/psf/black)
- 
-     |
-     |
- error: lint:call-non-callable
-    --> /tmp/mypy_primer/projects/black/src/blib2to3/pgen2/grammar.py:135:15
- 133 |         Copy the grammar.
- 134 |         """
- 135 |         new = self.__class__()
-     |               ^^^^^^^^^^^^^^^^ Object of type `type[@Todo]` is not callable
- 136 |         for dict_attr in (
- 137 |             "symbol2number",
- Found 328 diagnostics
+ Found 327 diagnostics
```
2025-03-10 13:24:13 +01:00
Alex Waygood
335b264fe2
[red-knot] Consistent spelling of "metaclass" and "meta-type" (#16576)
## Summary

Fixes a small nit of mine -- we are currently inconsistent in our
spelling between "metaclass" and "meta class", and between "meta type"
and "meta-type". This PR means that we consistently use "metaclass" and
"meta-type".

## Test Plan

`uvx pre-commit run -a`
2025-03-09 12:30:32 +00:00
David Peter
820a31af5d
[red-knot] Attribute access and the descriptor protocol (#16416)
## Summary

* Attributes/method are now properly looked up on metaclasses, when
called on class objects
* We properly distinguish between data descriptors and non-data
descriptors (but we do not yet support them in store-context, i.e.
`obj.data_descr = …`)
* The descriptor protocol is now implemented in a single unified place
for instances, classes and dunder-calls. Unions and possibly-unbound
symbols are supported in all possible stages of the process by creating
union types as results.
* In general, the handling of "possibly-unbound" symbols has been
improved in a lot of places: meta-class attributes, attributes,
descriptors with possibly-unbound `__get__` methods, instance
attributes, …
* We keep track of type qualifiers in a lot more places. I anticipate
that this will be useful if we import e.g. `Final` symbols from other
modules (see relevant change to typing spec:
https://github.com/python/typing/pull/1937).
* Detection and special-casing of the `typing.Protocol` special form in
order to avoid lots of changes in the test suite due to new `@Todo`
types when looking up attributes on builtin types which have `Protocol`
in their MRO. We previously
looked up attributes in a wrong way, which is why this didn't come up
before.

closes #16367
closes #15966

## Context

The way attribute lookup in `Type::member` worked before was simply
wrong (mostly my own fault). The whole instance-attribute lookup should
probably never have been integrated into `Type::member`. And the
`Type::static_member` function that I introduced in my last descriptor
PR was the wrong abstraction. It's kind of fascinating how far this
approach took us, but I am pretty confident that the new approach
proposed here is what we need to model this correctly.

There are three key pieces that are required to implement attribute
lookups:

- **`Type::class_member`**/**`Type::find_in_mro`**: The
`Type::find_in_mro` method that can look up attributes on class bodies
(and corresponding bases). This is a partial function on types, as it
can not be called on instance types like`Type::Instance(…)` or
`Type::IntLiteral(…)`. For this reason, we usually call it through
`Type::class_member`, which is essentially just
`type.to_meta_type().find_in_mro(…)` plus union/intersection handling.
- **`Type::instance_member`**: This new function is basically the
type-level equivalent to `obj.__dict__[name]` when called on
`Type::Instance(…)`. We use this to discover instance attributes such as
those that we see as declarations on class bodies or as (annotated)
assignments to `self.attr` in methods of a class.
- The implementation of the descriptor protocol. It works slightly
different for instances and for class objects, but it can be described
by the general framework:
- Call `type.class_member("attribute")` to look up "attribute" in the
MRO of the meta type of `type`. Call the resulting `Symbol` `meta_attr`
(even if it's unbound).
- Use `meta_attr.class_member("__get__")` to look up `__get__` on the
*meta type* of `meta_attr`. Call it with `__get__(meta_attr, self,
self.to_meta_type())`. If this fails (either the lookup or the call),
just proceed with `meta_attr`. Otherwise, replace `meta_attr` in the
following with the return type of `__get__`. In this step, we also probe
if a `__set__` or `__delete__` method exists and store it in
`meta_attr_kind` (can be either "data descriptor" or "normal attribute
or non-data descriptor").
  - Compute a `fallback` type.
    - For instances, we use `self.instance_member("attribute")`
- For class objects, we use `class_attr =
self.find_in_mro("attribute")`, and then try to invoke the descriptor
protocol on `class_attr`, i.e. we look up `__get__` on the meta type of
`class_attr` and call it with `__get__(class_attr, None, self)`. This
additional invocation of the descriptor protocol on the fallback type is
one major asymmetry in the otherwise universal descriptor protocol
implementation.
- Finally, we look at `meta_attr`, `meta_attr_kind` and `fallback`, and
handle various cases of (possible) unboundness of these symbols.
- If `meta_attr` is bound and a data descriptor, just return `meta_attr`
- If `meta_attr` is not a data descriptor, and `fallback` is bound, just
return `fallback`
- If `meta_attr` is not a data descriptor, and `fallback` is unbound,
return `meta_attr`
- Return unions of these three possibilities for partially-bound
symbols.

This allows us to handle class objects and instances within the same
framework. There is a minor additional detail where for instances, we do
not allow the fallback type (the instance attribute) to completely
shadow the non-data descriptor. We do this because we (currently) don't
want to pretend that we can statically infer that an instance attribute
is always set.

Dunder method calls can also be embedded into this framework. The only
thing that changes is that *there is no fallback type*. If a dunder
method is called on an instance, we do not fall back to instance
variables. If a dunder method is called on a class object, we only look
it up on the meta class, never on the class itself.

## Test Plan

New Markdown tests.
2025-03-07 22:03:28 +01:00
David Peter
0a627ef216
[red-knot] Never is callable and iterable. Arbitrary attributes can be accessed. (#16533)
## Summary

- `Never` is callable
- `Never` is iterable
- Arbitrary attributes can be accessed on `Never`

Split out from #16416 that is going to be required.

## Test Plan

Tests for all properties above.
2025-03-06 15:59:19 +00:00
Carl Meyer
87d011e1bd
[red-knot] fix non-callable reporting for unions (#16387)
Minor follow-up to https://github.com/astral-sh/ruff/pull/16161

This `not_callable` flag wasn't functional, because it could never be
`false`. It was initialized to `true` and then only ever updated with
`|=`, which can never make it `false`.

Add a test that exercises the case where it _should_ be `false` (all of
the union elements are callable) but `bindings` is also empty (all union
elements have binding errors). Before this PR, the added test wrongly
emits a diagnostic that the union `Literal[f1] | Literal[f2]` is not
callable.

And add a test where a union call results in one binding error and one
not-callable error, where we currently give the wrong result (we show
only the binding error), with a TODO.

Also add TODO comments in a couple other tests where ideally we'd report
more than just one error out of a union call.

Also update the flag name to `all_errors_not_callable` to more clearly
indicate the semantics of the flag.
2025-02-26 07:06:04 -08:00
David Peter
86b01d2d3c
[red-knot] Correct modeling of dunder calls (#16368)
## Summary

Model dunder-calls correctly (and in one single place), by implementing
this behavior (using `__getitem__` as an example).

```py
def getitem_desugared(obj: object, key: object) -> object:
    getitem_callable = find_in_mro(type(obj), "__getitem__")
    if hasattr(getitem_callable, "__get__"):
        getitem_callable = getitem_callable.__get__(obj, type(obj))

    return getitem_callable(key)
```

See the new `calls/dunder.md` test suite for more information. The new
behavior also needs much fewer lines of code (the diff is positive due
to new tests).

## Test Plan

New tests; fix TODOs in existing tests.
2025-02-25 20:38:15 +01:00
David Peter
aac79e453a
[red-knot] Better diagnostics for method calls (#16362)
## Summary

Add better error messages and additional spans for method calls. Can be
reviewed commit-by-commit.

before:

```
error: lint:invalid-argument-type
 --> /home/shark/playground/test.py:6:10
  |
5 | c = C()
6 | c.square("hello")  # error: [invalid-argument-type]
  |          ^^^^^^^ Object of type `Literal["hello"]` cannot be assigned to parameter 2 (`x`); expected type `int`
7 |
8 | # import inspect
  |
```

after:

```
error: lint:invalid-argument-type
 --> /home/shark/playground/test.py:6:10
  |
5 | c = C()
6 | c.square("hello")  # error: [invalid-argument-type]
  |          ^^^^^^^ Object of type `Literal["hello"]` cannot be assigned to parameter 2 (`x`) of bound method `square`; expected type `int`
7 |
8 | # import inspect
  |
 ::: /home/shark/playground/test.py:2:22
  |
1 | class C:
2 |     def square(self, x: int) -> int:
  |                      ------ info: parameter declared in function definition here
3 |         return x * x
  |
```

## Test Plan

New snapshot test
2025-02-25 09:58:08 +01:00
David Peter
141ba253da
[red-knot] Add support for @classmethods (#16305)
## 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
2025-02-24 09:55:34 +01:00
Alex Waygood
224a36f5f3
Teach red-knot that type(x) is the same as x.__class__ (#16301) 2025-02-21 21:05:48 +00:00
Micha Reiser
5fab97f1ef
[red-knot] Diagnostics for incorrect bool usages (#16238) 2025-02-21 19:26:05 +01:00
David Peter
d2e034adcd
[red-knot] Method calls and the descriptor protocol (#16121)
## Summary

This PR achieves the following:

* Add support for checking method calls, and inferring return types from
method calls. For example:
  ```py
  reveal_type("abcde".find("abc"))  # revealed: int
  reveal_type("foo".encode(encoding="utf-8"))  # revealed: bytes
  
  "abcde".find(123)  # error: [invalid-argument-type]
  
  class C:
      def f(self) -> int:
          pass
  
  reveal_type(C.f)  # revealed: <function `f`>
  reveal_type(C().f)  # revealed: <bound method: `f` of `C`>
  
  C.f()  # error: [missing-argument]
  reveal_type(C().f())  # revealed: int
  ```
* Implement the descriptor protocol, i.e. properly call the `__get__`
method when a descriptor object is accessed through a class object or an
instance of a class. For example:
  ```py
  from typing import Literal
  
  class Ten:
def __get__(self, instance: object, owner: type | None = None) ->
Literal[10]:
          return 10
  
  class C:
      ten: Ten = Ten()
  
  reveal_type(C.ten)  # revealed: Literal[10]
  reveal_type(C().ten)  # revealed: Literal[10]
  ```
* Add support for member lookup on intersection types.
* Support type inference for `inspect.getattr_static(obj, attr)` calls.
This was mostly used as a debugging tool during development, but seems
more generally useful. It can be used to bypass the descriptor protocol.
For the example above:
  ```py
  from inspect import getattr_static
  
  reveal_type(getattr_static(C, "ten"))  # revealed: Ten
  ```
* Add a new `Type::Callable(…)` variant with the following sub-variants:
* `Type::Callable(CallableType::BoundMethod(…))` — represents bound
method objects, e.g. `C().f` above
* `Type::Callable(CallableType::MethodWrapperDunderGet(…))` — represents
`f.__get__` where `f` is a function
* `Type::Callable(WrapperDescriptorDunderGet)` — represents
`FunctionType.__get__`
* Add new known classes:
  * `types.MethodType`
  * `types.MethodWrapperType`
  * `types.WrapperDescriptorType`
  * `builtins.range`

## Performance analysis

On this branch, we do more work. We need to do more call checking, since
we now check all method calls. We also need to do ~twice as many member
lookups, because we need to check if a `__get__` attribute exists on
accessed members.

A brief analysis on `tomllib` shows that we now call `Type::call` 1780
times, compared to 612 calls before.

## Limitations

* Data descriptors are not yet supported, i.e. we do not infer correct
types for descriptor attribute accesses in `Store` context and do not
check writes to descriptor attributes. I felt like this was something
that could be split out as a follow-up without risking a major
architectural change.
* We currently distinguish between `Type::member` (with descriptor
protocol) and `Type::static_member` (without descriptor protocol). The
former corresponds to `obj.attr`, the latter corresponds to
`getattr_static(obj, "attr")`. However, to model some details correctly,
we would also need to distinguish between a static member lookup *with*
and *without* instance variables. The lookup without instance variables
corresponds to `find_name_in_mro`
[here](https://docs.python.org/3/howto/descriptor.html#invocation-from-an-instance).
We currently approximate both using `member_static`, which leads to two
open TODOs. Changing this would be a larger refactoring of
`Type::own_instance_member`, so I chose to leave it out of this PR.

## Test Plan

* New `call/methods.md` test suite for method calls
* New tests in `descriptor_protocol.md`
* New `call/getattr_static.md` test suite for `inspect.getattr_static`
* Various updated tests
2025-02-20 23:22:26 +01:00
Micha Reiser
4ed5db0d42
Refactor CallOutcome to Result (#16161) 2025-02-18 13:34:39 +01:00
Carl Meyer
dcabb948f3
[red-knot] add special case for float/complex (#16166)
When adjusting the existing tests, I aimed to avoid dealing with the
special case in other tests if it's not necessary to do so (that is,
avoid using `float` and `complex` as examples where we just need "some
type"), and keep the tests for the special case mostly collected in the
mdtest dedicated to that purpose.

Fixes https://github.com/astral-sh/ruff/issues/14932
2025-02-14 12:24:10 -08:00
David Peter
1feb3cf41a
[red-knot] Use Unknown | T_inferred for undeclared public symbols (#15674)
## Summary

Use `Unknown | T_inferred` as the type for *undeclared* public symbols.

## Test Plan

- Updated existing tests
- New test for external `__slots__` modifications.
- New tests for external modifications of public symbols.
2025-01-24 12:47:48 +01:00
Carl Meyer
d54c19b983
[red-knot] remove CallOutcome::Cast variant (#15461)
## Summary

Simplification follow-up to #15413.

There's no need to have a dedicated `CallOutcome` variant for every
known function, it's only necessary if the special-cased behavior of the
known function includes emitting extra diagnostics. For `typing.cast`,
there's no such need; we can use the regular `Callable` outcome variant,
and update the return type according to the cast. (This is the same way
we already handle `len`.)

One reason to avoid proliferating unnecessary `CallOutcome` variants is
that currently we have to explicitly add emitting call-binding
diagnostics, for each outcome variant. So we were previously wrongly
silencing any binding diagnostics on calls to `typing.cast`. Fixing this
revealed a separate bug, that we were emitting a bogus error anytime
more than one keyword argument mapped to a `**kwargs` parameter. So this
PR also adds test and fix for that bug.

## Test Plan

Existing `cast` tests pass unchanged, added new test for `**kwargs` bug.
2025-01-13 10:58:53 -08:00
Carl Meyer
a95deec00f
[red-knot] handle synthetic 'self' argument in call-binding diagnostics (#15362) 2025-01-09 00:36:48 -08:00
David Peter
235fdfc57a
[red-knot] knot_extensions Python API (#15103)
## Summary

Adds a type-check-time Python API that allows us to create and
manipulate types and to test various of their properties. For example,
this can be used to write a Markdown test to make sure that `A & B` is a
subtype of `A` and `B`, but not of an unrelated class `C` (something
that requires quite a bit more code to do in Rust):
```py
from knot_extensions import Intersection, is_subtype_of, static_assert

class A: ...
class B: ...

type AB = Intersection[A, B]

static_assert(is_subtype_of(AB, A))
static_assert(is_subtype_of(AB, B))

class C: ...
static_assert(not is_subtype_of(AB, C))
```

I think this functionality is also helpful for interactive debugging
sessions, in order to query various properties of Red Knot's type
system. Which is something that otherwise requires a custom Rust unit
test, some boilerplate code and constant re-compilation.

## Test Plan

- New Markdown tests
- Tested the modified typeshed_sync workflow locally
2025-01-08 12:52:07 +01:00
Shaygan Hooshyari
03ff883626
Display Union of Literals as a Literal (#14993)
## Summary

Resolves #14988

Display union of Literals like other type checkers do.

With this change we lose the sorting behavior. And we show the types as
they appeared. So it's deterministic and tests should not be flaky.
This is similar to how Mypy [reveals the
type](https://mypy-play.net/?mypy=latest&python=3.12&gist=51ad03b153bfca3b940d5084345e230f).

In some cases this makes it harder to know what is the order in revealed
type when writing tests but since it's consistent after the test fails
we know the order.

## Test Plan

I adjusted mdtests for this change. Basically merged the int and string
types of the unions.

In cases where we have types other than numbers and strings like this
[one](https://github.com/astral-sh/ruff/pull/14993/files#diff-ac50bce02b9f0ad4dc7d6b8e1046d60dad919ac52d0aeb253e5884f89ea42bfeL51).
We only group the strings and numbers as the issue suggsted.

```
def _(flag: bool, flag2: bool):
    if flag:
        f = 1
    elif flag2:
        f = "foo"
    else:
        def f() -> int:
            return 1
    # error: "Object of type `Literal[1, "foo", f]` is not callable (due to union elements Literal[1], Literal["foo"])"
    # revealed: Unknown | int
    reveal_type(f())
```

[pyright
example](https://pyright-play.net/?code=GYJw9gtgBALgngBwJYDsDmUkQWEMoAySMApiAIYA2AUNQCYnBQD6AFMJeWgFxQBGYMJQA0UDlwBMvAUICU3alCWYm4nouWamAXigBGDUpKUkqzmimHNYqLoBEwQXavGAziQXXlDVa1lQAWgA%2BTBQYTy9rEBIYAFcQFH0rAGIoMnAQXjsAeT4AKxIAY3wwJngEEigAAyJSCkoAbT1RBydRYABdKsxXKBQwfEKqTj5KStY6WMqYMChYlCQwROMSCBIw3tqyKiaO0S36htawOw7ZZ01U6IA3EioSOl4AVRQAa36Ad0SAH1CYKxud0ozHKJHYflk1CAA)

[mypy
example](https://mypy-play.net/?mypy=latest&python=3.12&gist=31c8bdaa5521860cfeca4b92841cb3b7)

---------

Co-authored-by: Carl Meyer <carl@oddbird.net>
2025-01-08 00:58:38 +00:00
Carl Meyer
f2a86fcfda
[red-knot] add call checking (#15200)
## Summary

This implements checking of calls.

I ended up following Micha's original suggestion from back when the
signature representation was first introduced, and flattening it to a
single array of parameters. This turned out to be easier to manage,
because we can represent parameters using indices into that array, and
represent the bound argument types as an array of the same length.

Starred and double-starred arguments are still TODO; these won't be very
useful until we have generics.

The handling of diagnostics is just hacked into `return_ty_result`,
which was already inconsistent about whether it emitted diagnostics or
not; now it's even more inconsistent. This needs to be addressed, but
could be a follow-up.

The new benchmark errors here surface the need for intersection support
in `is_assignable_to`.

Fixes #14161.

## Test Plan

Added mdtests.
2025-01-07 20:39:45 +00:00
David Peter
000948ad3b
[red-knot] Statically known branches (#15019)
## Summary

This changeset adds support for precise type-inference and
boundness-handling of definitions inside control-flow branches with
statically-known conditions, i.e. test-expressions whose truthiness we
can unambiguously infer as *always false* or *always true*.

This branch also includes:
- `sys.platform` support
- statically-known branches handling for Boolean expressions and while
  loops
- new `target-version` requirements in some Markdown tests which were
  now required due to the understanding of `sys.version_info` branches.

closes #12700 
closes #15034 

## Performance

### `tomllib`, -7%, needs to resolve one additional module (sys)

| Command | Mean [ms] | Min [ms] | Max [ms] | Relative |
|:---|---:|---:|---:|---:|
| `./red_knot_main --project /home/shark/tomllib` | 22.2 ± 1.3 | 19.1 |
25.6 | 1.00 |
| `./red_knot_feature --project /home/shark/tomllib` | 23.8 ± 1.6 | 20.8
| 28.6 | 1.07 ± 0.09 |

### `black`, -6%

| Command | Mean [ms] | Min [ms] | Max [ms] | Relative |
|:---|---:|---:|---:|---:|
| `./red_knot_main --project /home/shark/black` | 129.3 ± 5.1 | 119.0 |
137.8 | 1.00 |
| `./red_knot_feature --project /home/shark/black` | 136.5 ± 6.8 | 123.8
| 147.5 | 1.06 ± 0.07 |

## Test Plan

- New Markdown tests for the main feature in
  `statically-known-branches.md`
- New Markdown tests for `sys.platform`
- Adapted tests for `EllipsisType`, `Never`, etc
2024-12-21 11:33:10 +01:00
Dhruv Manilawala
dcdc6e7c64
[red-knot] Avoid undeclared path when raising conflicting declarations (#14958)
## Summary

This PR updates the logic when raising conflicting declarations
diagnostic to avoid the undeclared path if present.

The conflicting declaration diagnostics is added when there are two or
more declarations in the control flow path of a definition whose type
isn't equivalent to each other. This can be seen in the following
example:

```py
if flag:
	x: int
x = 1  # conflicting-declarations: Unknown, int
```

After this PR, we'd avoid considering "Unknown" as part of the
conflicting declarations. This means we'd still flag it for the
following case:

```py
if flag:
	x: int
else:
	x: str
x = 1  # conflicting-declarations: int, str
```

A solution that's local to the exception control flow was also explored
which required updating the logic for merging the flow snapshot to avoid
considering declarations using a flag. This is preserved here:
https://github.com/astral-sh/ruff/compare/dhruv/control-flow-no-declarations?expand=1.

The main motivation to avoid that is we don't really understand what the
user experience is w.r.t. the Unknown type and the
conflicting-declaration diagnostics. This makes us unsure on what the
right semantics are as to whether that diagnostics should be raised or
not and when to raise them. For now, we've decided to move forward with
this PR and could decide to adopt another solution or remove the
conflicting-declaration diagnostics in the future.

Closes: #13966 

## Test Plan

Update the existing mdtest case. Add an additional case specific to
exception control flow to verify that the diagnostic is not being raised
now.
2024-12-17 09:49:39 +05:30
InSync
15fe540251
Improve mdtests style (#14884)
Co-authored-by: Alex Waygood <alex.waygood@gmail.com>
2024-12-10 13:05:51 +00:00
David Peter
47f39ed1a0
[red-knot] Meta data for Type::Todo (#14500)
## 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.
2024-11-21 09:59:47 +01:00
Carl Meyer
a48d779c4e
[red-knot] function signature representation (#14304)
## Summary

Add a typed representation of function signatures (parameters and return
type) and infer it correctly from a function.

Convert existing usage of function return types to use the signature
representation.

This does not yet add inferred types for parameters within function body
scopes based on the annotations, but it should be easy to add as a next
step.

Part of #14161 and #13693.

## Test Plan

Added tests.
2024-11-14 23:34:24 +00:00
David Peter
4f74db5630
[red-knot] Improve Symbol API for callable types (#14137)
## Summary

- Get rid of `Symbol::unwrap_or` (unclear semantics, not needed anymore)
- Introduce `Type::call_dunder`
- Emit new diagnostic for possibly-unbound `__iter__` methods
- Better diagnostics for callables with possibly-unbound /
possibly-non-callable `__call__` methods

part of: #14022 

closes #14016

## Test Plan

- Updated test for iterables with possibly-unbound `__iter__` methods.
- New tests for callables
2024-11-07 19:58:31 +01:00
Micha Reiser
6aaf1d9446
[red-knot] Remove lint-phase (#13922)
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
2024-10-25 18:40:52 +00:00
Alex Waygood
3eb454699a
[red-knot] Format mdtest Python snippets more concisely (#13905) 2024-10-24 11:09:31 +00:00
Alex Waygood
36cb1199cc
[red-knot] Autoformat mdtest Python snippets using blacken-docs (#13809) 2024-10-19 15:57:06 +01:00
David Peter
c2f7c39987
[red-knot] mdtest suite: formatting and cleanup (#13806)
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
2024-10-18 11:07:53 +02:00
Alex
d77480768d
[red-knot] Port type inference tests to new test framework (#13719)
## Summary

Porting infer tests to new markdown tests framework.

Link to the corresponding issue: #13696

---------

Co-authored-by: Carl Meyer <carl@astral.sh>
2024-10-15 11:23:46 -07:00