Apply ruff/bugbear rules (B) (#787)

* Apply ruff/bugbear rule B904

	B904 Within an `except` clause, raise exceptions with `raise ... from err` or
	     `raise ... from None` to distinguish them from errors in exception handling

* Apply ruff/bugbear rule B028

	B028 No explicit `stacklevel` keyword argument found

* Apply ruff/bugbear rule B018

	B018 Found useless expression. Either assign it to a variable or remove it.

* Do not ignore ruff/bugbear rule (B015)

https://docs.astral.sh/ruff/rules/useless-comparison/

* Do not ignore ruff/bugbear rule (B009)

https://docs.astral.sh/ruff/rules/get-attr-with-constant/

pyproject.toml

@@ -74,12 +74,7 @@ extend-select = [
     "W"
 ]
 ignore = [
-    "B009",
-    "B015",
-    "B018",
     "B027",
-    "B028",
-    "B904",
     "N818",
     "RUF003",
     "RUF012",

src/packaging/_elffile.py

@@ -48,8 +48,8 @@ def __init__(self, f: IO[bytes]) -> None:
 
         try:
             ident = self._read("16B")
-        except struct.error:
-            raise ELFInvalid("unable to parse identification")
+        except struct.error as e:
+            raise ELFInvalid("unable to parse identification") from e
         magic = bytes(ident[:4])
         if magic != b"\x7fELF":
             raise ELFInvalid(f"invalid magic: {magic!r}")
@@ -67,11 +67,11 @@ def __init__(self, f: IO[bytes]) -> None:
                 (2, 1): ("<HHIQQQIHHH", "<IIQQQQQQ", (0, 2, 5)),  # 64-bit LSB.
                 (2, 2): (">HHIQQQIHHH", ">IIQQQQQQ", (0, 2, 5)),  # 64-bit MSB.
             }[(self.capacity, self.encoding)]
-        except KeyError:
+        except KeyError as e:
             raise ELFInvalid(
                 f"unrecognized capacity ({self.capacity}) or "
                 f"encoding ({self.encoding})"
-            )
+            ) from e
 
         try:
             (

src/packaging/_manylinux.py

@@ -164,6 +164,7 @@ def _parse_glibc_version(version_str: str) -> tuple[int, int]:
             f"Expected glibc version with 2 components major.minor,"
             f" got: {version_str}",
             RuntimeWarning,
+            stacklevel=2,
         )
         return -1, -1
     return int(m.group("major")), int(m.group("minor"))

src/packaging/metadata.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import builtins
 import email.feedparser
 import email.header
 import email.message
@@ -21,9 +22,9 @@
 T = typing.TypeVar("T")
 
 
-try:
-    ExceptionGroup
-except NameError:  # pragma: no cover
+if "ExceptionGroup" in builtins.__dict__:  # pragma: no cover
+    ExceptionGroup = ExceptionGroup
+else:  # pragma: no cover
 
     class ExceptionGroup(Exception):
         """A minimal implementation of :external:exc:`ExceptionGroup` from Python 3.11.
@@ -42,9 +43,6 @@ def __init__(self, message: str, exceptions: list[Exception]) -> None:
         def __repr__(self) -> str:
             return f"{self.__class__.__name__}({self.message!r}, {self.exceptions!r})"
 
-else:  # pragma: no cover
-    ExceptionGroup = ExceptionGroup
-
 
 class InvalidMetadata(ValueError):
     """A metadata field contains invalid data."""
@@ -224,8 +222,8 @@ def _get_payload(msg: email.message.Message, source: bytes | str) -> str:
         bpayload: bytes = msg.get_payload(decode=True)
         try:
             return bpayload.decode("utf8", "strict")
-        except UnicodeDecodeError:
-            raise ValueError("payload in an invalid encoding")
+        except UnicodeDecodeError as exc:
+            raise ValueError("payload in an invalid encoding") from exc
 
 
 # The various parse_FORMAT functions here are intended to be as lenient as
@@ -535,7 +533,7 @@ def _process_name(self, value: str) -> str:
         except utils.InvalidName as exc:
             raise self._invalid_metadata(
                 f"{value!r} is invalid for {{field}}", cause=exc
-            )
+            ) from exc
         else:
             return value
 
@@ -547,7 +545,7 @@ def _process_version(self, value: str) -> version_module.Version:
         except version_module.InvalidVersion as exc:
             raise self._invalid_metadata(
                 f"{value!r} is invalid for {{field}}", cause=exc
-            )
+            ) from exc
 
     def _process_summary(self, value: str) -> str:
         """Check the field contains no newlines."""
@@ -608,7 +606,7 @@ def _process_provides_extra(
         except utils.InvalidName as exc:
             raise self._invalid_metadata(
                 f"{name!r} is invalid for {{field}}", cause=exc
-            )
+            ) from exc
         else:
             return normalized_names
 
@@ -618,7 +616,7 @@ def _process_requires_python(self, value: str) -> specifiers.SpecifierSet:
         except specifiers.InvalidSpecifier as exc:
             raise self._invalid_metadata(
                 f"{value!r} is invalid for {{field}}", cause=exc
-            )
+            ) from exc
 
     def _process_requires_dist(
         self,
@@ -629,7 +627,9 @@ def _process_requires_dist(
             for req in value:
                 reqs.append(requirements.Requirement(req))
         except requirements.InvalidRequirement as exc:
-            raise self._invalid_metadata(f"{req!r} is invalid for {{field}}", cause=exc)
+            raise self._invalid_metadata(
+                f"{req!r} is invalid for {{field}}", cause=exc
+            ) from exc
         else:
             return reqs
 

tests/test_metadata.py

@@ -427,7 +427,7 @@ def test_invalid_metadata_version(self, version):
         meta = metadata.Metadata.from_raw({"metadata_version": version}, validate=False)
 
         with pytest.raises(metadata.InvalidMetadata):
-            meta.metadata_version
+            meta.metadata_version  # noqa: B018
 
     def test_valid_version(self):
         version_str = "1.2.3"
@@ -437,7 +437,7 @@ def test_valid_version(self):
     def test_missing_version(self):
         meta = metadata.Metadata.from_raw({}, validate=False)
         with pytest.raises(metadata.InvalidMetadata) as exc_info:
-            meta.version
+            meta.version  # noqa: B018
         assert exc_info.value.field == "version"
 
     def test_invalid_version(self):
@@ -456,7 +456,7 @@ def test_invalid_summary(self):
         )
 
         with pytest.raises(metadata.InvalidMetadata) as exc_info:
-            meta.summary
+            meta.summary  # noqa: B018
         assert exc_info.value.field == "summary"
 
     def test_valid_name(self):
@@ -506,7 +506,7 @@ def test_invalid_description_content_type(self, content_type):
         )
 
         with pytest.raises(metadata.InvalidMetadata):
-            meta.description_content_type
+            meta.description_content_type  # noqa: B018
 
     def test_keywords(self):
         keywords = ["hello", "world"]
@@ -602,14 +602,14 @@ def test_invalid_dynamic_value(self):
         meta = metadata.Metadata.from_raw({"dynamic": dynamic}, validate=False)
 
         with pytest.raises(metadata.InvalidMetadata):
-            meta.dynamic
+            meta.dynamic  # noqa: B018
 
     @pytest.mark.parametrize("field_name", ["name", "version", "metadata-version"])
     def test_disallowed_dynamic(self, field_name):
         meta = metadata.Metadata.from_raw({"dynamic": [field_name]}, validate=False)
 
         with pytest.raises(metadata.InvalidMetadata):
-            meta.dynamic
+            meta.dynamic  # noqa: B018
 
     @pytest.mark.parametrize(
         "field_name",