Allow auto-loading of plugins in certain conditions (#3762)

Ref: https://github.com/matmair/InvenTree/commit/52af1966941ce564bae485988c40b8161d6f201e

InvenTree/InvenTree/ready.py

@@ -13,7 +13,7 @@ def isImportingData():
     return 'loaddata' in sys.argv
 
 
-def canAppAccessDatabase(allow_test=False):
+def canAppAccessDatabase(allow_test: bool = False, allow_plugins: bool = False):
     """Returns True if the apps.py file can access database records.
 
     There are some circumstances where we don't want the ready function in apps.py
@@ -25,8 +25,6 @@ def canAppAccessDatabase(allow_test=False):
         'flush',
         'loaddata',
         'dumpdata',
-        'makemigrations',
-        'migrate',
         'check',
         'shell',
         'createsuperuser',
@@ -43,6 +41,12 @@ def canAppAccessDatabase(allow_test=False):
         # Override for testing mode?
         excluded_commands.append('test')
 
+    if not allow_plugins:
+        excluded_commands.extend([
+            'makemigrations',
+            'migrate',
+        ])
+
     for cmd in excluded_commands:
         if cmd in sys.argv:
             return False

InvenTree/plugin/apps.py

@@ -27,7 +27,7 @@ class PluginAppConfig(AppConfig):
     def ready(self):
         """The ready method is extended to initialize plugins."""
         if settings.PLUGINS_ENABLED:
-            if not canAppAccessDatabase(allow_test=True):
+            if not canAppAccessDatabase(allow_test=True, allow_plugins=True):
                 logger.info("Skipping plugin loading sequence")  # pragma: no cover
             else:
                 logger.info('Loading InvenTree plugins')