From 8dc594c05580275f8b071fe4b1128be77f9be391 Mon Sep 17 00:00:00 2001
From: Manuel Barkhau <mbarkhau@gmail.com>
Date: Thu, 4 May 2023 14:37:15 +0000
Subject: [PATCH] Fix #200 - Use looseversion if pkg_resources doesn't work

---
 CHANGELOG.md           |  7 +++++++
 requirements/pypi.txt  |  4 +++-
 src/bumpver/version.py | 10 ++++++++--
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b712217..556262d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,12 @@
 # Changelog for https://github.com/mbarkhau/bumpver
 
+## BumpVer 2023.1121
+
+- Fix [#200][gh_i200]: Fix compatability with packaging 23.0.
+
+[gh_i200]: https://github.com/mbarkhau/bumpver/issues/200
+
+
 ## BumpVer 2022.1120
 
 - Fix [#196][gh_i196]: Add `--pin-increments`.
diff --git a/requirements/pypi.txt b/requirements/pypi.txt
index 391d643..243a810 100644
--- a/requirements/pypi.txt
+++ b/requirements/pypi.txt
@@ -15,7 +15,9 @@ toml
 lexid
 colorama>=0.4
 
+# looseversion is needed to parse non PEP440 versions
+looseversion; python_version >= "3.5"
+
 # setuptools is needed for pkg_resources.parse_version
 # Support for Python 2 was dropped with v45
 setuptools<45.0.0; python_version < "3.5"
-setuptools>=45.0.0; python_version >= "3.5"
diff --git a/src/bumpver/version.py b/src/bumpver/version.py
index 90aff43..0eff7ac 100644
--- a/src/bumpver/version.py
+++ b/src/bumpver/version.py
@@ -11,9 +11,15 @@ MaybeInt = typ.Optional[int]
 
 def parse_version(version: str) -> typ.Any:
     # pylint: disable=import-outside-toplevel; lazy import to speed up --help
-    import pkg_resources
 
-    return pkg_resources.parse_version(version)
+    try:
+        import pkg_resources
+
+        return pkg_resources.parse_version(version)
+    except (ImportError, pkg_resources.extern.packaging.version.InvalidVersion):
+        import looseversion
+
+        return looseversion.LooseVersion(version)
 
 
 class V1CalendarInfo(typ.NamedTuple):