perf: use version.__replace__ in specifier comparison

[notatallshaw]

Takes advantage of being able to strip parts of a Version and get a Version without having to revalidate a version string.

Not had chance to benchmark this yet, but should significantly improve performance of specifier comparison when local, pre, post, or dev parts are involved.

[henryiii]

Would this also make sense to add to this PR?

diff --git a/src/packaging/specifiers.py b/src/packaging/specifiers.py
index f027aeb..2ba5541 100644
--- a/src/packaging/specifiers.py
+++ b/src/packaging/specifiers.py
@@ -420,7 +420,7 @@ class Specifier(BaseSpecifier):
         if spec.endswith(".*"):
             # In the case of prefix matching we want to ignore local segment.
             normalized_prospective = canonicalize_version(
-                prospective.public, strip_trailing_zero=False
+                _public_version(prospective), strip_trailing_zero=False
             )
             # Get the normalized version string ignoring the trailing .*
             normalized_spec = canonicalize_version(spec[:-2], strip_trailing_zero=False)

Also _canonical_spec access self._spec[1] directly and converts it to a version inside canonicalize_version, maybe that should use _get_spec_version instead? Also maybe _spec[1] could be cached separately, as _get_spec_version will change the cache to a different value if a different version is passed into it? Unless it's always called with the same value. I also see it used directly in a few other places, like .prerelease.

Full patch:

diff --git a/src/packaging/specifiers.py b/src/packaging/specifiers.py
index f027aeb..18edd34 100644
--- a/src/packaging/specifiers.py
+++ b/src/packaging/specifiers.py
@@ -285,11 +285,13 @@ class Specifier(BaseSpecifier):
             # The == specifier can include a trailing .*, if it does we
             # want to remove before parsing.
             if operator == "==" and version.endswith(".*"):
-                version = version[:-2]
+                version_object = Version(version[:-2])
+            else:
+                version_object = self._get_spec_version(version)

             # Parse the version, and if it is a pre-release than this
             # specifier allows pre-releases.
-            if Version(version).is_prerelease:
+            if version_object.is_prerelease:
                 return True

         return False
@@ -351,7 +353,7 @@ class Specifier(BaseSpecifier):
             return operator, version

         canonical_version = canonicalize_version(
-            version,
+            version if version.endswith(".*") else self._get_spec_version(version),
             strip_trailing_zero=(operator != "~="),
         )

@@ -420,7 +422,7 @@ class Specifier(BaseSpecifier):
         if spec.endswith(".*"):
             # In the case of prefix matching we want to ignore local segment.
             normalized_prospective = canonicalize_version(
-                prospective.public, strip_trailing_zero=False
+                _public_version(prospective), strip_trailing_zero=False
             )
             # Get the normalized version string ignoring the trailing .*
             normalized_spec = canonicalize_version(spec[:-2], strip_trailing_zero=False)

[notatallshaw]

Would this also make sense to add to this PR?

Yes, turns out there were two places I was missing public and base version calls where I could have been using them.

Also _canonical_spec access self._spec[1] directly and converts it to a version inside canonicalize_version, maybe that should use _get_spec_version instead? Also maybe _spec[1] could be cached separately, as _get_spec_version will change the cache to a different value if a different version is passed into it? Unless it's always called with the same value. I also see it used directly in a few other places, like .prerelease.

I would need to carefully go over this, the one-element cache is always called with the same value at the moment (assuming you don't mutate the specifier, in which case the cache invalidates itself when you call _get_spec_version), I need to validate that it would always be the same version under _canonical_spec.