Require Python >=3.9 + optional strenum fallback

Fallback with package `strenum` is required for Python < 3.11.

Part-of: <https://gitlab.freedesktop.org/xkeyboard-config/xkeyboard-config/-/merge_requests/702>

2 files changed, 17 insertions, 6 deletions

diff --git a/rules/generate-options-symbols.py b/rules/generate-options-symbols.py
index b29b9253..5eec9b7d 100755
--- a/rules/generate-options-symbols.py
+++ b/rules/generate-options-symbols.py
@@ -7,14 +7,20 @@
 
 from __future__ import annotations
 import argparse
-from enum import StrEnum, unique
+from enum import unique
 import sys
 import xml.etree.ElementTree as ET
-
 from typing import Generator, Iterable
 from dataclasses import dataclass
 from pathlib import Path
 
+try:
+    # Available from Python 3.11
+    from enum import StrEnum
+except ImportError:
+    # Fallback to external package
+    from strenum import StrEnum
+
 
 def error(msg):
     print(f"ERROR: {msg}", file=sys.stderr)
diff --git a/rules/meson.build b/rules/meson.build
index 0978150e..414ea5f2 100644
--- a/rules/meson.build
+++ b/rules/meson.build
@@ -127,13 +127,18 @@ if get_option('compat-rules')
 endif # compat-rules
 
 MINIMUM_PYTHON_VERSION = '3.11'
+MINIMUM_PYTHON_VERSION_WITH_MODULE_FALLBACK = '3.9'
 pymod = import('python')
 python = pymod.find_installation('python3')
 if python.language_version().version_compare('<@0@'.format(MINIMUM_PYTHON_VERSION))
-    error('Minimum required Python version: @0@, but got: @1@'.format(
-        MINIMUM_PYTHON_VERSION,
-        python.language_version()
-    ))
+    # Now require strenum module as fallback
+    python = pymod.find_installation('python3', modules: ['strenum'])
+    if python.language_version().version_compare('<@0@'.format(MINIMUM_PYTHON_VERSION_WITH_MODULE_FALLBACK))
+        error('Minimum required Python version: @0@, but got: @1@'.format(
+            MINIMUM_PYTHON_VERSION_WITH_MODULE_FALLBACK,
+            python.language_version()
+        ))
+    endif
 endif
 merge_py = find_program('merge.py')
 xml2lst = find_program('xml2lst.pl')