chore: add ruff TC (#980)

* chore: add ruff TC

Signed-off-by: Henry Schreiner <[email protected]>

* chore: coverage should skip type checking blocks

Signed-off-by: Henry Schreiner <[email protected]>

* Refactor import of Self for compatibility

---------

Signed-off-by: Henry Schreiner <[email protected]>

Author: henryiii

pyproject.toml

@@ -64,7 +64,7 @@ source_pkgs = ["packaging"]
 [tool.coverage.report]
 show_missing = true
 fail_under = 100
-exclude_also = ["@abc.abstractmethod", "@abc.abstractproperty"]
+exclude_also = ["@abc.abstractmethod", "@abc.abstractproperty", "if typing.TYPE_CHECKING:"]
 
 [tool.pytest.ini_options]
 minversion = "6.2"
@@ -123,6 +123,7 @@ extend-select = [
     "SLOT",  # flake8-slots
     "T10",   # flake8-debugger
     "T20",   # flake8-print
+    "TC",    # flake8-type-checking
     "TRY",   # tryceratops
     "UP",    # pyupgrade
     "W",

src/packaging/licenses/__init__.py

@@ -142,6 +142,6 @@ def canonicalize_license_expression(
     normalized_expression = " ".join(normalized_tokens)
 
     return cast(
-        NormalizedLicenseExpression,
+        "NormalizedLicenseExpression",
         normalized_expression.replace("( ", "(").replace(" )", ")"),
     )

src/packaging/markers.py

@@ -356,7 +356,7 @@ def _repair_python_full_version(
     Work around platform.python_version() returning something that is not PEP 440
     compliant for non-tagged Python builds.
     """
-    python_full_version = cast(str, env["python_full_version"])
+    python_full_version = cast("str", env["python_full_version"])
     if python_full_version.endswith("+"):
         env["python_full_version"] = f"{python_full_version}local"
     return env

src/packaging/metadata.py

@@ -20,7 +20,9 @@
 
 from . import licenses, requirements, specifiers, utils
 from . import version as version_module
-from .licenses import NormalizedLicenseExpression
+
+if typing.TYPE_CHECKING:
+    from .licenses import NormalizedLicenseExpression
 
 T = typing.TypeVar("T")
 
@@ -498,7 +500,7 @@ def parse_email(data: bytes | str) -> tuple[RawMetadata, dict[str, list[str]]]:
             # Check to see if we've already got a description, if so then both
             # it, and this body move to unparsable.
             if "description" in raw:
-                description_header = cast(str, raw.pop("description"))
+                description_header = cast("str", raw.pop("description"))
                 unparsed.setdefault("description", []).extend(
                     [description_header, payload]
                 )
@@ -511,7 +513,7 @@ def parse_email(data: bytes | str) -> tuple[RawMetadata, dict[str, list[str]]]:
     # literal key names, but we're computing our key names on purpose, but the
     # way this function is implemented, our `TypedDict` can only have valid key
     # names.
-    return cast(RawMetadata, raw), unparsed
+    return cast("RawMetadata", raw), unparsed
 
 
 _NOT_FOUND = object()
@@ -574,7 +576,7 @@ def __get__(self, instance: Metadata, _owner: type[Metadata]) -> T:
         except KeyError:
             pass
 
-        return cast(T, value)
+        return cast("T", value)
 
     def _invalid_metadata(
         self, msg: str, cause: Exception | None = None
@@ -589,7 +591,7 @@ def _process_metadata_version(self, value: str) -> _MetadataVersion:
         # Implicitly makes Metadata-Version required.
         if value not in _VALID_METADATA_VERSIONS:
             raise self._invalid_metadata(f"{value!r} is not a valid metadata version")
-        return cast(_MetadataVersion, value)
+        return cast("_MetadataVersion", value)
 
     def _process_name(self, value: str) -> str:
         if not value:

src/packaging/pylock.py

@@ -3,11 +3,9 @@
 import dataclasses
 import logging
 import re
-import sys
 from collections.abc import Mapping, Sequence
 from dataclasses import dataclass
 from datetime import datetime
-from pathlib import Path
 from typing import (
     TYPE_CHECKING,
     Any,
@@ -22,10 +20,9 @@
 from .version import Version
 
 if TYPE_CHECKING:  # pragma: no cover
-    if sys.version_info >= (3, 11):
-        from typing import Self
-    else:
-        from typing_extensions import Self
+    from pathlib import Path
+
+    from typing_extensions import Self
 
 _logger = logging.getLogger(__name__)
 

src/packaging/utils.py

@@ -48,7 +48,7 @@ def canonicalize_name(name: str, *, validate: bool = False) -> NormalizedName:
         raise InvalidName(f"name is invalid: {name!r}")
     # This is taken from PEP 503.
     value = _canonicalize_regex.sub("-", name).lower()
-    return cast(NormalizedName, value)
+    return cast("NormalizedName", value)
 
 
 def is_normalized_name(name: str) -> bool:
@@ -127,7 +127,7 @@ def parse_wheel_filename(
             raise InvalidWheelFilename(
                 f"Invalid build number: {build_part} in {filename!r}"
             )
-        build = cast(BuildTag, (int(build_match.group(1)), build_match.group(2)))
+        build = cast("BuildTag", (int(build_match.group(1)), build_match.group(2)))
     else:
         build = ()
     tags = parse_tag(parts[-1])