packaging: restore Python 3.7 support

version_file support is only available in setuptools_scm 8.0,
and older versions throw errors when pyproject.toml contains
configuration that the older versions do not understand.

This means that we cannot use version_file just yet if
we want to retain support for Python 3.7.

Restore the importlib.metadata version lookups alongside
the setuptools_scm version file support so that we can
swap over later once we are okay dropping support for 3.7.

Signed-off-by: David Aguilar <davvid@gmail.com>

cola/version.py

@@ -1,4 +1,14 @@
 """Provide git-cola's version number"""
+import sys
+
+try:
+    if sys.version_info < (3, 8):
+        import importlib_metadata as metadata
+    else:
+        from importlib import metadata
+except (ImportError, OSError):
+    metadata = None
+
 from .git import STDOUT
 from .decorators import memoize
 from ._version import VERSION
@@ -56,6 +66,11 @@ def version():
         pkg_version = SCM_VERSION
     else:
         pkg_version = VERSION
+        if metadata is not None:
+            try:
+                pkg_version = metadata.version('git-cola')
+            except (ImportError, OSError):
+                pass
     return pkg_version
 
 

pyproject.toml

@@ -36,4 +36,3 @@ addopts = "--ruff"
 
 [tool.setuptools_scm]
 fallback_version = "4.7.0"
-version_file = "cola/_scm_version.py"

setup.cfg

@@ -24,6 +24,7 @@ packages =
 	cola.widgets
 include_package_data = true
 install_requires =
+	importlib_metadata; python_version<"3.8"
 	polib >= 1.0.0
 	qtpy >= 1.1.0
 zip_safe = false