Merge with 8.18.2

1 files changed, 27 insertions, 9 deletions

diff --git a/pkg_resources.py b/pkg_resources.py
index 5af4c869..87fd2782 100644
--- a/pkg_resources.py
+++ b/pkg_resources.py
@@ -80,6 +80,13 @@ import setuptools._vendor.packaging.specifiers
 packaging = setuptools._vendor.packaging
 
 
+class PEP440Warning(RuntimeWarning):
+    """
+    Used when there is an issue with a version or specifier not complying with
+    PEP 440.
+    """
+
+
 class _SetuptoolsVersionMixin(object):
 
     def __hash__(self):
@@ -272,6 +279,9 @@ __all__ = [
     'ResolutionError', 'VersionConflict', 'DistributionNotFound',
     'UnknownExtra', 'ExtractionError',
 
+    # Warnings
+    'PEP440Warning',
+
     # Parsing functions and string utilities
     'parse_requirements', 'parse_version', 'safe_name', 'safe_version',
     'get_platform', 'compatible_platforms', 'yield_lines', 'split_sections',
@@ -2415,15 +2425,23 @@ class Distribution(object):
             self._parsed_version = parse_version(self.version)
             if isinstance(
                     self._parsed_version, packaging.version.LegacyVersion):
-                warnings.warn(
-                    "'%s (%s)' is being parsed as a legacy, non PEP 440, "
-                    "version. You may find odd behavior and sort order. In "
-                    "particular it will be sorted as less than 0.0. It is "
-                    "recommend to migrate to PEP 440 compatible versions." % (
-                        self.project_name, self.version,
-                    ),
-                    RuntimeWarning,
-                )
+                # While an empty version is techincally a legacy version and
+                # is not a valid PEP 440 version, it's also unlikely to
+                # actually come from someone and instead it is more likely that
+                # it comes from setuptools attempting to parse a filename and
+                # including it in the list. So for that we'll gate this warning
+                # on if the version is anything at all or not.
+                if self.version:
+                    warnings.warn(
+                        "'%s (%s)' is being parsed as a legacy, non PEP 440, "
+                        "version. You may find odd behavior and sort order. "
+                        "In particular it will be sorted as less than 0.0. It "
+                        "is recommend to migrate to PEP 440 compatible "
+                        "versions." % (
+                            self.project_name, self.version,
+                        ),
+                        PEP440Warning,
+                    )
 
         return self._parsed_version