## 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#12700closes#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
## Summary
Refer:
https://github.com/astral-sh/ruff/issues/13773#issuecomment-2548020368
This PR adds support for unpacking union types.
Unpacking a union type requires us to first distribute the types for all
the targets that are involved in an unpacking. For example, if there are
two targets and a union type that needs to be unpacked, each target will
get a type from each element in the union type.
For example, if the type is `tuple[int, int] | tuple[int, str]` and the
target has two elements `(a, b)`, then
* The type of `a` will be a union of `int` and `int` which are at index
0 in the first and second tuple respectively which resolves to an `int`.
* Similarly, the type of `b` will be a union of `int` and `str` which
are at index 1 in the first and second tuple respectively which will be
`int | str`.
### Refactors
There are couple of refactors that are added in this PR:
* Add a `debug_assertion` to validate that the unpack target is a list
or a tuple
* Add a separate method to handle starred expression
## Test Plan
Update `unpacking.md` with additional test cases that uses union types.
This is done using parameter type hints style.
## Summary
This PR adds initial support for `type: ignore`. It doesn't do anything
fancy yet like:
* Detecting invalid type ignore comments
* Detecting type ignore comments that are part of another suppression
comment: `# fmt: skip # type: ignore`
* Suppressing specific lints `type: ignore [code]`
* Detecting unsused type ignore comments
* ...
The goal is to add this functionality in separate PRs.
## Test Plan
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
We have a handy `to_meta_type` that does the right thing for class
instances, and also works for all of the other types that are “instances
of” something. Unless I'm missing something, this should let us get rid
of the catch-all clause in one fell swoop.
cf #14548
This tweaks the new semantics from #15026 a bit when a symbol could be
interpreted both as an attribute and a submodule of a package. For
`from...import`, we should actually prioritize the attribute, because of
how the statement itself is implemented [1].
> 1. check if the imported module has an attribute by that name
> 2. if not, attempt to import a submodule with that name and then check
the imported module again for that attribute
[1] https://docs.python.org/3/reference/simple_stmts.html#the-import-statement
## Summary
Fixes#14550.
Add `AlwaysTruthy` and `AlwaysFalsy` types, representing the set of objects whose `__bool__` method can only ever return `True` or `False`, respectively, and narrow `if x` and `if not x` accordingly.
## Test Plan
- New Markdown test for truthiness narrowing `narrow/truthiness.md`
- unit tests in `types.rs` and `builders.rs` (`cargo test --package
red_knot_python_semantic --lib -- types`)
## 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.
When importing a nested module, we were correctly creating a binding for
the top-most parent, but we were binding that to the nested module, not
to that parent module. Moreover, we weren't treating those submodules as
members of their containing parents. This PR addresses both issues, so
that nested imports work as expected.
As discussed in ~Slack~ whatever chat app I find myself in these days
😄, this requires keeping track of which modules have been imported
within the current file, so that when we resolve member access on a
module reference, we can see if that member has been imported as a
submodule. If so, we return the submodule reference immediately, instead
of checking whether the parent module's definition defines the symbol.
This is currently done in a flow insensitive manner. The `SemanticIndex`
now tracks all of the modules that are imported (via `import`, not via
`from...import`). The member access logic mentioned above currently only
considers module imports in the file containing the attribute
expression.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
Resolves#14922.
## Test Plan
Markdown tests.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Co-authored-by: Carl Meyer <carl@astral.sh>
## Summary
This is not strictly required yet, but makes these tests future-proof.
They need a `python-version` requirement as they rely on language
features that are not available in 3.9.
## Summary
Add support for `typing.TYPE_CHECKING` and
`typing_extensions.TYPE_CHECKING`.
relates to: https://github.com/astral-sh/ruff/issues/14170
## Test Plan
New Markdown-based tests
## Summary
This PR renames the `--custom-typeshed-dir`, `target-version`, and
`--current-directory` cli options to `--typeshed`,
`--python-version`, and `--project` as discussed in the CLI proposal
document.
I added aliases for `--target-version` (for Ruff compat) and
`--custom-typeshed-dir` (for Alex)
## Test Plan
Long help
```
An extremely fast Python type checker.
Usage: red_knot [OPTIONS] [COMMAND]
Commands:
server Start the language server
help Print this message or the help of the given subcommand(s)
Options:
--project <PROJECT>
Run the command within the given project directory.
All `pyproject.toml` files will be discovered by walking up the directory tree from the project root, as will the project's virtual environment (`.venv`).
Other command-line arguments (such as relative paths) will be resolved relative to the current working directory."#,
--venv-path <PATH>
Path to the virtual environment the project uses.
If provided, red-knot will use the `site-packages` directory of this virtual environment to resolve type information for the project's third-party dependencies.
--typeshed-path <PATH>
Custom directory to use for stdlib typeshed stubs
--extra-search-path <PATH>
Additional path to use as a module-resolution source (can be passed multiple times)
--python-version <VERSION>
Python version to assume when resolving types
[possible values: 3.7, 3.8, 3.9, 3.10, 3.11, 3.12, 3.13]
-v, --verbose...
Use verbose output (or `-vv` and `-vvv` for more verbose output)
-W, --watch
Run in watch mode by re-running whenever files change
-h, --help
Print help (see a summary with '-h')
-V, --version
Print version
```
Short help
```
An extremely fast Python type checker.
Usage: red_knot [OPTIONS] [COMMAND]
Commands:
server Start the language server
help Print this message or the help of the given subcommand(s)
Options:
--project <PROJECT> Run the command within the given project directory
--venv-path <PATH> Path to the virtual environment the project uses
--typeshed-path <PATH> Custom directory to use for stdlib typeshed stubs
--extra-search-path <PATH> Additional path to use as a module-resolution source (can be passed multiple times)
--python-version <VERSION> Python version to assume when resolving types [possible values: 3.7, 3.8, 3.9, 3.10, 3.11, 3.12, 3.13]
-v, --verbose... Use verbose output (or `-vv` and `-vvv` for more verbose output)
-W, --watch Run in watch mode by re-running whenever files change
-h, --help Print help (see more with '--help')
-V, --version Print version
```
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
Regression test(s) for something that broken while implementing #14759.
We have similar tests for other control flow elements, but feel free to
let me know if this seems superfluous.
## Test Plan
New mdtests
## Summary
Using `typing.LiteralString` breaks as soon as we understand
`sys.version_info` branches, as it's only available in 3.11 and later.
## Test Plan
Made sure it didn't fail on my #14759 branch anymore.
We support using `typing.Type[]` as a base class (and we have tests for
it), but not yet `builtins.type[]`. At some point we should fix that,
but I don't think it';s worth spending much time on now (and it might be
easier once we've implemented generics?). This PR just adds a failing
test with a TODO.
This adds support for `type[Any]`, which represents an unknown type (not
an instance of an unknown type), and `type`, which we are choosing to
interpret as `type[object]`.
Closes#14546
## Summary
This is the second PR out of three that adds support for
enabling/disabling lint rules in Red Knot. You may want to take a look
at the [first PR](https://github.com/astral-sh/ruff/pull/14869) in this
stack to familiarize yourself with the used terminology.
This PR adds a new syntax to define a lint:
```rust
declare_lint! {
/// ## What it does
/// Checks for references to names that are not defined.
///
/// ## Why is this bad?
/// Using an undefined variable will raise a `NameError` at runtime.
///
/// ## Example
///
/// ```python
/// print(x) # NameError: name 'x' is not defined
/// ```
pub(crate) static UNRESOLVED_REFERENCE = {
summary: "detects references to names that are not defined",
status: LintStatus::preview("1.0.0"),
default_level: Level::Warn,
}
}
```
A lint has a name and metadata about its status (preview, stable,
removed, deprecated), the default diagnostic level (unless the
configuration changes), and documentation. I use a macro here to derive
the kebab-case name and extract the documentation automatically.
This PR doesn't yet add any mechanism to discover all known lints. This
will be added in the next and last PR in this stack.
## Documentation
I documented some rules but then decided that it's probably not my best
use of time if I document all of them now (it also means that I play
catch-up with all of you forever). That's why I left some rules
undocumented (marked with TODO)
## Where is the best place to define all lints?
I'm not sure. I think what I have in this PR is fine but I also don't
love it because most lints are in a single place but not all of them. If
you have ideas, let me know.
## Why is the message not part of the lint, unlike Ruff's `Violation`
I understand that the main motivation for defining `message` on
`Violation` in Ruff is to remove the need to repeat the same message
over and over again. I'm not sure if this is an actual problem. Most
rules only emit a diagnostic in a single place and they commonly use
different messages if they emit diagnostics in different code paths,
requiring extra fields on the `Violation` struct.
That's why I'm not convinced that there's an actual need for it and
there are alternatives that can reduce the repetition when creating a
diagnostic:
* Create a helper function. We already do this in red knot with the
`add_xy` methods
* Create a custom `Diagnostic` implementation that tailors the entire
diagnostic and pre-codes e.g. the message
Avoiding an extra field on the `Violation` also removes the need to
allocate intermediate strings as it is commonly the place in Ruff.
Instead, Red Knot can use a borrowed string with `format_args`
## Test Plan
`cargo test`
This adds support for `type[a.X]`, where the `type` special form is
applied to a qualified name that resolves to a class literal. This works
for both nested classes and classes imported from another module.
Closes#14545
## Summary
Inferred and declared types for function parameters, in the function
body scope.
Fixes#13693.
## Test Plan
Added mdtests.
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
`typing.Never` and `typing.LiteralString` are only conditionally
exported from `typing` for Python versions 3.11 and later. We run the
Markdown tests with the default Python version of 3.9, so here we change
the import to `typing_extensions` instead, and add a new test to make
sure we'll continue to understand the `typing`-version of these symbols
for newer versions.
This didn't cause problems so far, as we don't understand
`sys.version_info` branches yet.
## Test Plan
New Markdown tests to make sure this will continue to work in the
future.
## Summary
This adds support for specifying the target Python version from a
Markdown test. It is a somewhat limited ad-hoc solution, but designed to
be future-compatible. TOML blocks can be added to arbitrary sections in
the Markdown block. They have the following format:
````markdown
```toml
[tool.knot.environment]
target-version = "3.13"
```
````
So far, there is nothing else that can be configured, but it should be
straightforward to extend this to things like a custom typeshed path.
This is in preparation for the statically-known branches feature where
we are going to have to specify the target version for lots of tests.
## Test Plan
- New Markdown test that fails without the explicitly specified
`target-version`.
- Manually tested various error paths when specifying a wrong
`target-version` field.
- Made sure that running tests is as fast as before.
## Summary
This is related to #13778, more specifically
https://github.com/astral-sh/ruff/issues/13778#issuecomment-2513556004.
This PR adds various test cases where a keyword is being where an
identifier is expected. The tests are to make sure that red knot doesn't
panic, raises the syntax error and the identifier is added to the symbol
table. The final part allows editor related features like renaming the
symbol.
