Refactor migration dependencies to avoid issue when going backward

djangocms_blog/migrations/0001_initial.py

@@ -17,14 +17,23 @@ ACTUAL_FILER_IMAGE_MODEL = FILER_IMAGE_MODEL or 'filer.Image'
 
 class Migration(migrations.Migration):
 
+    if 'cmsplugin_filer' not in thumbnail_model:
+        filer_dependencies = [
+            ('filer', '0003_thumbnailoption'),
+            ('cmsplugin_filer_image', '0006_auto_20160427_1438')
+        ]
+    else:
+        filer_dependencies = [
+            ('filer', '__first__'),
+            ('cmsplugin_filer_image', '__first__'),
+        ]
+
     dependencies = [
         migrations.swappable_dependency(settings.AUTH_USER_MODEL),
         migrations.swappable_dependency(ACTUAL_FILER_IMAGE_MODEL),
-        ('cms', '__latest__'),
-        ('taggit', '__latest__'),
-        ('filer', '__latest__'),
-        ('cmsplugin_filer_image', '__latest__'),
-    ]
+        ('cms', '__first__'),
+        ('taggit', '__first__'),
+    ] + filer_dependencies
 
     operations = [
         migrations.CreateModel(

djangocms_blog/migrations/0002_post_sites.py

@@ -7,7 +7,7 @@ from django.db import models, migrations
 class Migration(migrations.Migration):
 
     dependencies = [
-        ('sites', '__latest__'),
+        ('sites', '__first__'),
         ('djangocms_blog', '0001_initial'),
     ]
 

djangocms_blog/migrations/0009_latestpostsplugin_tags_new.py

@@ -31,7 +31,7 @@ def migrate_tags_reverse(apps, schema_editor):
 class Migration(migrations.Migration):
 
     dependencies = [
-        ('taggit', '__latest__'),
+        ('taggit', '__first__'),
         ('djangocms_blog', '0008_auto_20150814_0831'),
     ]
 

djangocms_blog/migrations/0010_auto_20150923_1151.py

@@ -10,7 +10,7 @@ from django.db import models, migrations
 class Migration(migrations.Migration):
 
     dependencies = [
-        ('cms', '__latest__'),
+        ('cms', '__first__'),
         ('djangocms_blog', '0009_latestpostsplugin_tags_new'),
     ]
 

djangocms_blog/models.py

@@ -32,18 +32,12 @@ from .settings import get_setting
 BLOG_CURRENT_POST_IDENTIFIER = get_setting('CURRENT_POST_IDENTIFIER')
 BLOG_CURRENT_NAMESPACE = get_setting('CURRENT_NAMESPACE')
 
-try:
-    from cmsplugin_filer_image.models import ThumbnailOption  # NOQA
-except ImportError:
+try:  # pragma: no cover
     from filer.models import ThumbnailOption  # NOQA
-try:
-    thumbnail_model = '%s.%s' % (
-        ThumbnailOption._meta.app_label, ThumbnailOption._meta.model_name
-    )
-except AttributeError:
-    thumbnail_model = '%s.%s' % (
-        ThumbnailOption._meta.app_label, ThumbnailOption._meta.module_name
-    )
+    thumbnail_model = 'filer.ThumbnailOption'
+except ImportError:  # pragma: no cover
+    from cmsplugin_filer_image.models import ThumbnailOption  # NOQA
+    thumbnail_model = 'cmsplugin_filer_image.ThumbnailOption'
 
 
 try: