Fix migration path. (#128)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: jackton1

migration_fixer/management/commands/makemigrations.py

@@ -3,7 +3,6 @@
 """
 
 import os
-import pathlib
 from functools import partial
 
 from django.apps import apps
@@ -17,6 +16,7 @@
 from migration_fixer.utils import (
     fix_numbered_migration,
     get_filename,
+    get_migration_module_path,
     migration_sorter,
     no_translations,
     sibling_nodes,
@@ -178,12 +178,7 @@ def handle(self, *app_labels, **options):
                     for app_label in conflicts:
                         conflict = conflicts[app_label]
                         migration_module, _ = loader.migrations_module(app_label)
-                        migration_absolute_path = os.path.join(
-                            *migration_module.split(".")
-                        )
-                        migration_path = pathlib.Path(
-                            os.path.join(settings.BASE_DIR, migration_absolute_path)
-                        )
+                        migration_path = get_migration_module_path(migration_module)
 
                         with migration_path:
                             if self.verbosity >= 2:
@@ -200,9 +195,9 @@ def handle(self, *app_labels, **options):
                                     diff.b_path
                                     for diff in diff_index
                                     if (
-                                        migration_absolute_path
+                                        str(migration_path)
                                         in getattr(diff.a_blob, "abspath", "")
-                                        or migration_absolute_path
+                                        or str(migration_path)
                                         in getattr(diff.b_blob, "abspath", "")
                                     )
                                 ]

migration_fixer/utils.py

@@ -1,5 +1,6 @@
 import os
 import re
+from importlib import import_module
 from itertools import count
 from pathlib import Path
 from typing import Callable, List, Optional
@@ -127,6 +128,20 @@ def get_filename(path: str) -> str:
     return os.path.splitext(os.path.basename(path))[0]
 
 
+def get_migration_module_path(migration_module_path: str) -> Path:
+    try:
+        migration_module = import_module(migration_module_path)
+    except ImportError as e:
+        if "bad magic number" in str(e):
+            raise ImportError(
+                f"Couldn't import {migration_module_path} as it appears to be a stale .pyc file."
+            ) from e
+        else:
+            raise
+
+    return Path(os.path.dirname(os.path.abspath(migration_module.__file__)))
+
+
 def sibling_nodes(graph: MigrationGraph, app_name: Optional[str] = None) -> List[str]:
     """
     Return all sibling nodes that have the same parent