use the canonical parsers from packaging for getting the package name

Author: RonnyPfannschmidt

src/setuptools_scm/_integration/pyproject_reading.py

@@ -7,6 +7,7 @@
 from typing import Sequence
 
 from .. import _log
+from .._requirement_cls import extract_package_name
 from .toml import TOML_RESULT
 from .toml import read_toml_content
 
@@ -75,12 +76,7 @@ def has_build_package(
     requires: Sequence[str], build_package_names: Sequence[str]
 ) -> bool:
     for requirement in requires:
-        import re
-
-        # Remove extras like [toml] first
-        clean_req = re.sub(r"\[.*?\]", "", requirement)
-        # Split on version operators and take first part
-        package_name = re.split(r"[><=!~]", clean_req)[0].strip().lower()
+        package_name = extract_package_name(requirement).lower()
         if package_name in build_package_names:
             return True
     return False

src/setuptools_scm/_integration/setuptools.py

@@ -39,25 +39,6 @@ def _warn_on_old_setuptools(_version: str = setuptools.__version__) -> None:
         )
 
 
-def _extract_package_name(requirement: str) -> str:
-    """Extract the package name from a requirement string.
-
-    Examples:
-        'setuptools_scm' -> 'setuptools_scm'
-        'setuptools-scm>=8' -> 'setuptools-scm'
-        'setuptools_scm[toml]>=7.0' -> 'setuptools_scm'
-    """
-    # Split on common requirement operators and take the first part
-    # This handles: >=, <=, ==, !=, >, <, ~=
-    import re
-
-    # Remove extras like [toml] first
-    requirement = re.sub(r"\[.*?\]", "", requirement)
-    # Split on version operators
-    package_name = re.split(r"[><=!~]", requirement)[0].strip()
-    return package_name
-
-
 def _assign_version(
     dist: setuptools.Distribution, config: _config.Configuration
 ) -> None:

src/setuptools_scm/_requirement_cls.py

@@ -0,0 +1,32 @@
+from __future__ import annotations
+
+try:
+    from packaging.requirements import Requirement
+    from packaging.utils import canonicalize_name
+except ImportError:
+    from setuptools.extern.packaging.requirements import (  # type: ignore[import-not-found,no-redef]
+        Requirement as Requirement,
+    )
+    from setuptools.extern.packaging.utils import (  # type: ignore[import-not-found,no-redef]
+        canonicalize_name as canonicalize_name,
+    )
+
+from . import _log
+
+log = _log.log.getChild("requirement_cls")
+
+
+def extract_package_name(requirement_string: str) -> str:
+    """Extract the canonical package name from a requirement string.
+
+    This function uses packaging.requirements.Requirement to properly parse
+    the requirement and extract the package name, handling all edge cases
+    that the custom regex-based approach might miss.
+
+    Args:
+        requirement_string: The requirement string to parse
+
+    Returns:
+        The package name as a string
+    """
+    return canonicalize_name(Requirement(requirement_string).name)

testing/test_integration.py

@@ -18,11 +18,12 @@
 
 import setuptools_scm._integration.setuptools
 
+from setuptools_scm._requirement_cls import extract_package_name
+
 if TYPE_CHECKING:
     import setuptools
 
 from setuptools_scm import Configuration
-from setuptools_scm._integration.setuptools import _extract_package_name
 from setuptools_scm._integration.setuptools import _warn_on_old_setuptools
 from setuptools_scm._overrides import PRETEND_KEY
 from setuptools_scm._overrides import PRETEND_KEY_NAMED
@@ -826,7 +827,7 @@ def test_pyproject_build_system_requires_priority_over_tool_section(
 )
 def test_extract_package_name(base_name: str, requirements: str) -> None:
     """Test the _extract_package_name helper function"""
-    assert _extract_package_name(f"{base_name}{requirements}") == base_name
+    assert extract_package_name(f"{base_name}{requirements}") == "setuptools-scm"
 
 
 def test_build_requires_integration_with_config_reading(wd: WorkDir) -> None: