[red-knot] knot_extensions Python API

.github/workflows/sync_typeshed.yaml

@@ -46,6 +46,10 @@ jobs:
           cp -r typeshed/stdlib ruff/crates/red_knot_vendored/vendor/typeshed/stdlib
           rm -rf ruff/crates/red_knot_vendored/vendor/typeshed/stdlib/@tests
           git -C typeshed rev-parse HEAD > ruff/crates/red_knot_vendored/vendor/typeshed/source_commit.txt
+          # Patch the typeshed stubs to include `knot_extensions`
+          ln -s ../../../knot_extensions/knot_extensions.pyi ruff/crates/red_knot_vendored/vendor/typeshed/stdlib/
+          echo "# Patch applied for red_knot:" >> ruff/crates/red_knot_vendored/vendor/typeshed/stdlib/VERSIONS
+          echo "knot_extensions: 3.0-" >> ruff/crates/red_knot_vendored/vendor/typeshed/stdlib/VERSIONS
       - name: Commit the changes
         id: commit
         if: ${{ steps.sync.outcome == 'success' }}

crates/red_knot_vendored/knot_extensions/README.md

@@ -0,0 +1,3 @@
+The `knot_extensions.pyi` file in this directory will be symlinked into
+the `vendor/typeshed/stdlib` directory every time we sync our `typeshed`
+stubs (see `.github/workflows/sync_typeshed.yaml`).

crates/red_knot_vendored/knot_extensions/knot_extensions.pyi

@@ -0,0 +1,24 @@
+from typing import _SpecialForm, Any, LiteralString
+
+# Special operations
+def static_assert(condition: object, msg: LiteralString | None = None) -> None: ...
+
+# Types
+Unknown = object()
+
+# Special forms
+Not: _SpecialForm
+Intersection: _SpecialForm
+TypeOf: _SpecialForm
+
+# Predicates on types
+#
+# Ideally, these would be annotated using `TypeForm`, but that has not been
+# standardized yet (https://peps.python.org/pep-0747).
+def is_equivalent_to(type_a: Any, type_b: Any) -> bool: ...
+def is_subtype_of(type_derived: Any, typ_ebase: Any) -> bool: ...
+def is_assignable_to(type_target: Any, type_source: Any) -> bool: ...
+def is_disjoint_from(type_a: Any, type_b: Any) -> bool: ...
+def is_fully_static(type: Any) -> bool: ...
+def is_singleton(type: Any) -> bool: ...
+def is_single_valued(type: Any) -> bool: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/VERSIONS

@@ -341,4 +341,5 @@ zipfile._path: 3.12-
 zipimport: 3.0-
 zlib: 3.0-
 zoneinfo: 3.9-
+# Patch applied for red_knot:
 knot_extensions: 3.0-

crates/red_knot_vendored/vendor/typeshed/stdlib/knot_extensions.pyi

@@ -0,0 +1 @@
+../../../knot_extensions/knot_extensions.pyi