## Summary
Under preview 🧪 I've expanded rule `PYI016` to also flag type
union duplicates containing `None` and `Optional`.
## Test Plan
Examples/tests have been added. I've made sure that the existing
examples did not change unless preview is enabled.
## Relevant Issues
* https://github.com/astral-sh/ruff/issues/18508 (discussing
introducing/extending a rule to flag `Optional[None]`)
* https://github.com/astral-sh/ruff/issues/18546 (where I discussed this
addition with @AlexWaygood)
---------
Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>
Essentially this PR ensures that when we do fixes like this:
```diff
- t"{set(f(x) for x in foo)}"
+ t"{ {f(x) for x in foo} }"
```
we are correctly adding whitespace around the braces.
This logic is already in place for f-strings and just needed to be
generalized to interpolated strings.
## Summary
Garbage collect ASTs once we are done checking a given file. Queries
with a cross-file dependency on the AST will reparse the file on demand.
This reduces ty's peak memory usage by ~20-30%.
The primary change of this PR is adding a `node_index` field to every
AST node, that is assigned by the parser. `ParsedModule` can use this to
create a flat index of AST nodes any time the file is parsed (or
reparsed). This allows `AstNodeRef` to simply index into the current
instance of the `ParsedModule`, instead of storing a pointer directly.
The indices are somewhat hackily (using an atomic integer) assigned by
the `parsed_module` query instead of by the parser directly. Assigning
the indices in source-order in the (recursive) parser turns out to be
difficult, and collecting the nodes during semantic indexing is
impossible as `SemanticIndex` does not hold onto a specific
`ParsedModuleRef`, which the pointers in the flat AST are tied to. This
means that we have to do an extra AST traversal to assign and collect
the nodes into a flat index, but the small performance impact (~3% on
cold runs) seems worth it for the memory savings.
Part of https://github.com/astral-sh/ty/issues/214.
This PR implements template strings (t-strings) in the parser and
formatter for Ruff.
Minimal changes necessary to compile were made in other parts of the code (e.g. ty, the linter, etc.). These will be covered properly in follow-up PRs.
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
## Summary
Includes minor changes to the semantic type inference to help detect the
return type of function call.
Fixes#17691
## Test Plan
Snapshot tests
Summary
--
While going through the syntax errors in [this comment], I was surprised
to see the error `name 'x' is assigned to before global declaration`,
which corresponds to [load-before-global-declaration (PLE0118)] and has
also been reimplemented as a syntax error (#17135). However, it looks
like neither of the implementations consider `global` declarations in
the top-level module scope, which is a syntax error in CPython:
```python
# try.py
x = None
global x
```
```shell
> python -m compileall -f try.py
Compiling 'try.py'...
*** File "try.py", line 2
global x
^^^^^^^^
SyntaxError: name 'x' is assigned to before global declaration
```
I'm not sure this is the best or most elegant solution, but it was a
quick fix that passed all of our tests.
Test Plan
--
New PLE0118 test case.
[this comment]:
https://github.com/astral-sh/ruff/issues/7633#issuecomment-1740424031
[load-before-global-declaration (PLE0118)]:
https://docs.astral.sh/ruff/rules/load-before-global-declaration/#load-before-global-declaration-ple0118
## Summary
Based on the discussion in
https://github.com/astral-sh/ruff/pull/17298#discussion_r2033975460, we
decided to move the scope handling out of the `SemanticSyntaxChecker`
and into the `SemanticSyntaxContext` trait. This PR implements that
refactor by:
- Reverting all of the `Checkpoint` and `in_async_context` code in the
`SemanticSyntaxChecker`
- Adding four new methods to the `SemanticSyntaxContext` trait
- `in_async_context`: matches `SemanticModel::in_async_context` and only
detects the nearest enclosing function
- `in_sync_comprehension`: uses the new `is_async` tracking on
`Generator` scopes to detect any enclosing sync comprehension
- `in_module_scope`: reports whether we're at the top-level scope
- `in_notebook`: reports whether we're in a Jupyter notebook
- In-lining the `TestContext` directly into the
`SemanticSyntaxCheckerVisitor`
- This allows modifying the context as the visitor traverses the AST,
which wasn't possible before
One potential question here is "why not add a single method returning a
`Scope` or `Scopes` to the context?" The main reason is that the `Scope`
type is defined in the `ruff_python_semantic` crate, which is not
currently a dependency of the parser. It also doesn't appear to be used
in red-knot. So it seemed best to use these more granular methods
instead of trying to access `Scope` in `ruff_python_parser` (and
red-knot).
## Test Plan
Existing parser and linter tests.
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## Summary
I decided to disable the new
[`needless_continue`](https://rust-lang.github.io/rust-clippy/master/index.html#needless_continue)
rule because I often found the explicit `continue` more readable over an
empty block or having to invert the condition of an other branch.
## Test Plan
`cargo test`
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
We add support for `return` and `raise` statements in the control flow
graph: we simply add an edge to the terminal block, push the statements
to the current block, and proceed.
This implementation will have to be modified somewhat once we add
support for `try` statements - then we will need to check whether to
_defer_ the jump. But for now this will do!
Also in this PR: We fix the `unreachable` diagnostic range so that it
lumps together consecutive unreachable blocks.
This PR contains the scaffolding for a new control flow graph
implementation, along with its application to the `unreachable` rule. At
the moment, the implementation is a maximal over-approximation: no
control flow is modeled and all statements are counted as reachable.
With each additional statement type we support, this approximation will
improve.
So this PR just contains:
- A `ControlFlowGraph` struct and builder
- Support for printing the flow graph as a Mermaid graph
- Snapshot tests for the actual graphs
- (a very bad!) reimplementation of `unreachable` using the new structs
- Snapshot tests for `unreachable`
# Instructions for Viewing Mermaid snapshots
Unfortunately I don't know how to convince GitHub to render the Mermaid
graphs in the snapshots. However, you can view these locally in VSCode
if you install an extension that supports Mermaid graphs in Markdown,
and then add this to your `settings.json`:
```json
"files.associations": {
"*.md.snap": "markdown",
}
```
## Summary
This PR implements the "greeter" approach for checking the AST for
syntax errors emitted by the CPython compiler. It introduces two main
infrastructural changes to support all of the compile-time errors:
1. Adds a new `semantic_errors` module to the parser crate with public
`SemanticSyntaxChecker` and `SemanticSyntaxError` types
2. Embeds a `SemanticSyntaxChecker` in the `ruff_linter::Checker` for
checking these errors in ruff
As a proof of concept, it also implements detection of two syntax
errors:
1. A reimplementation of
[`late-future-import`](https://docs.astral.sh/ruff/rules/late-future-import/)
(`F404`)
2. Detection of rebound comprehension iteration variables
(https://github.com/astral-sh/ruff/issues/14395)
## Test plan
Existing F404 tests, new inline tests in the `ruff_python_parser` crate,
and a linter CLI test showing an example of the `Message` output.
I also tested in VS Code, where `preview = false` and turning off syntax
errors both disable the new errors:

And on the playground, where `preview = false` also disables the errors:

Fixes#14395
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
## Summary
This PR stabilizes the preview behavior introduced in
https://github.com/astral-sh/ruff/pull/15719 to recognize all symbols
named `TYPE_CHECKING` as type-checking
checks in `if TYPE_CHECKING` conditions. This ensures compatibility with
mypy and pyright.
This PR also stabilizes the new behavior that removes `if 0:` and `if
False` to be no longer considered type checking blocks.
Since then, this syntax has been removed from the typing spec and was
only used for Python modules that don't have a `typing` module
([comment](https://github.com/astral-sh/ruff/pull/15719#issuecomment-2612787793)).
The preview behavior was first released with Ruff 0.9.5 (6th of
February), which was about a month ago. There are no open issues or PRs
for the changed behavior
## Test Plan
The snapshots for `SIM108` change because `SIM108` ignored type checking
blocks but it can no
simplify `if 0` or `if False` blocks again because they're no longer
considered type checking blocks.
The changes in the `TC005` snapshot or only due to that `if 0` and `if
False` are no longer recognized as type checking blocks
<!-- How was it tested? -->
## Summary
Follow-up to #15984.
Previously, `PLE1310` would only report when the object is a literal:
```python
'a'.strip('//') # error
foo = ''
foo.strip('//') # no error
```
After this change, objects whose type can be inferred to be either `str`
or `bytes` will also be reported in preview.
## Test Plan
`cargo nextest run` and `cargo insta test`.
## Summary
This change resolves#15814 to ensure that `SIM401` is only triggered on
known dictionary types. Before, the rule was getting triggered even on
types that _resemble_ a dictionary but are not actually a dictionary.
I did this using the `is_known_to_be_of_type_dict(...)` functionality.
The logic for this function was duplicated in a few spots, so I moved
the code to a central location, removed redundant definitions, and
updated existing calls to use the single definition of the function!
## Test Plan
Since this PR only modifies an existing rule, I made changes to the
existing test instead of adding new ones. I made sure that `SIM401` is
triggered on types that are clearly dictionaries and that it's not
triggered on a simple custom dictionary-like type (using a modified
version of [the code in the issue](#15814))
The additional changes to de-duplicate `is_known_to_be_of_type_dict`
don't break any existing tests -- I think this should be fine since the
logic remains the same (please let me know if you think otherwise, I'm
excited to get feedback and work towards a good fix 🙂).
---------
Co-authored-by: Junhson Jean-Baptiste <junhsonjb@naan.mynetworksettings.com>
Co-authored-by: Micha Reiser <micha@reiser.io>
Closes#15681
## Summary
This changes `analyze::typing::is_type_checking_block` to recognize all
symbols named "TYPE_CHECKING".
This matches the current behavior of mypy and pyright as well as
`flake8-type-checking`.
It also drops support for detecting `if False:` and `if 0:` as type
checking blocks. This used to be an option for
providing backwards compatibility with Python versions that did not have
a `typing` module, but has since
been removed from the typing spec and is no longer supported by any of
the mainstream type checkers.
## Test Plan
`cargo nextest run`
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
Previously an error was emitted any time the configuration required both
an import of a module and an alias for that module. However, required
imports could themselves contain an alias, which may or may not agree
with the required alias.
To wit: requiring `import pandas as pd` does not conflict with the
`flake8-import-conventions.alias` config `{"pandas":"pd"}`.
This PR refines the check before throwing an error.
Closes#15911
## Summary
Fixes https://github.com/astral-sh/ruff/issues/15812 by visiting the
second argument as a type definition.
## Test Plan
New F401 tests based on the report.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
Resolves#12717.
This change incorporates the logic added in #15588.
## Test Plan
`cargo nextest run` and `cargo insta test`.
---------
Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com>
The AST generator creates a reference enum for each syntax group — an
enum where each variant contains a reference to the relevant syntax
node. Previously you could customize the name of the reference enum for
a group — primarily because there was an existing `ExpressionRef` type
that wouldn't have lined up with the auto-derived name `ExprRef`. This
follow-up PR is a simple search/replace to switch over to the
auto-derived name, so that we can remove this customization point.
In the following situation:
```python
class Grandparent:
__slots__ = "a"
class Parent(Grandparent): ...
class Child(Parent):
__slots__ = "a"
```
the message for `W0244` now specifies that `a` is overwriting a slot
from `Grandparent`.
To implement this, we introduce a helper function `iter_super_classes`
which does a breadth-first traversal of the superclasses of a given
class (as long as they are defined in the same file, due to the usual
limitations of the semantic model).
Note: Python does not allow conflicting slots definitions under multiple
inheritance. Unless I'm misunderstanding something, I believe It follows
that the subposet of superclasses of a given class that redefine a given
slot is in fact totally ordered. There is therefore a unique _nearest_
superclass whose slot is being overwritten. So, you know, in case anyone
was super worried about that... you can just chill.
This is a followup to #9640 .
## Summary
This fixes the infinite loop reported in #14389 by raising an error to
the user about conflicting ICN001 (`unconventional-import-alias`) and
I002 (`missing-required-import`) configuration options.
## Test Plan
Added a CLI integration test reproducing the old behavior and then
confirming the fix.
Closes#14389
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Closes#14000
## Summary
For typing context bindings we know that they won't be available at
runtime. We shouldn't recommend a fix, that will result in name errors
at runtime.
## Test Plan
`cargo nextest run`
## Summary
Part 1 of the big change introduced in #14828. This temporarily causes
all fixes for `round(...)` to be considered unsafe, but they will
eventually be enhanced.
## Test Plan
`cargo nextest run` and `cargo insta test`.