refactor: do not use StrEnum as it only appears in Python 3.11

Author: sgaist

repo2docker/app.py

@@ -478,7 +478,7 @@ def _dry_run_changed(self, change):
     ignore_file_strategy = Enum(
         ExcludesStrategy.values(),
         config=True,
-        default_value=ExcludesStrategy.theirs,
+        default_value=ExcludesStrategy.THEIRS.value,
         help="""
         Strategy to use if an extra ignore file is passed:
         - merge means that the content of the extra ignore file will be merged
@@ -888,7 +888,9 @@ def build(self):
                         self.extra_build_kwargs,
                         platform=self.platform,
                         extra_ignore_file=self.extra_ignore_file,
-                        ignore_file_strategy=self.ignore_file_strategy,
+                        ignore_file_strategy=ExcludesStrategy(
+                            self.ignore_file_strategy
+                        ),
                     ):
                         if docker_client.string_output:
                             self.log.info(l, extra=dict(phase=R2dState.BUILDING))

repo2docker/buildpacks/base.py

@@ -7,7 +7,7 @@
 import sys
 import tarfile
 import textwrap
-from enum import StrEnum, auto
+from enum import Enum
 from functools import lru_cache
 
 import escapism
@@ -206,10 +206,10 @@
 DEFAULT_NB_UID = 1000
 
 
-class ExcludesStrategy(StrEnum):
-    theirs = auto()
-    ours = auto()
-    merge = auto()
+class ExcludesStrategy(Enum):
+    THEIRS = "theirs"
+    OURS = "ours"
+    MERGE = "merge"
 
     @classmethod
     def values(cls):
@@ -594,7 +594,7 @@ def build(
         extra_build_kwargs,
         platform=None,
         extra_ignore_file=None,
-        ignore_file_strategy=ExcludesStrategy.theirs,
+        ignore_file_strategy=ExcludesStrategy.THEIRS,
     ):
         tarf = io.BytesIO()
         tar = tarfile.open(fileobj=tarf, mode="w")
@@ -640,9 +640,9 @@ def _read_excludes(filepath):
                 excludes.extend(_read_excludes(ignore_file_name))
 
         if extra_ignore_file is not None:
-            if ignore_file_strategy == ExcludesStrategy.ours:
+            if ignore_file_strategy == ExcludesStrategy.OURS:
                 excludes = extra_excludes
-            elif ignore_file_strategy == ExcludesStrategy.merge:
+            elif ignore_file_strategy == ExcludesStrategy.MERGE:
                 excludes.extend(extra_excludes)
             else:
                 # ignore means that if an ignore file exist, its content is used