AAP-17690 Inventory variables sourced from git project are not getting deleted after being removed from source (#15928) (#6946)

* Delete existing all-group vars on inventory sync (with overwrite-vars=True) instead of merging them.

* Implementation of inv var handling with file as db.

* Improve serialization to file of inv vars for src update

* Include inventory-level variable editing into inventory source update handling

* Add group vars to inventory source update handling

* Add support for overwrite_vars to new inventory source handling

* Persist inventory var history in the database instead of a file.

* Remove logging which was needed during development.

* Remove further debugging code and improve comments

* Move special handling for user edits of variables into serializers

* Relate the inventory variable history model to its inventory

* Allow for inventory variables to have the value 'None'

* Fix KeyError in new inventory variable handling

* Add unique-together constraint for new model InventoryGroupVariablesWithHistory

* Use only one special invsrc_id for initial update and manual updates

* Fix internal server error when creating a new inventory

* Print the empty string for a variable with value 'None'

* Fix comment which incorrectly states old behaviour

* Fix inventory_group_variables_update tests which did not take the new handling of None into account

* Allow any type for Ansible-core variable values

* Refactor misleading method names

* Fix internal server error when savig vars from group form

* Remove superfluous json conversion in front of JSONField

* Call variable update from create/update instead from validate

* Use group_id instead of group_name in model InventoryGroupVariablesWithHistory

* Disable new variable update handling for all regular (non-'all') groups

* Add live test to verify AAP-17690 (inv var deleted from source)

* Add functional tests to verify inventory variables update logic

* Fix migration which was corrupted by a rebase

* Add a more complex live test and resolve linter complaints

* Force overwrite_vars=False for updates from source on all-group

* Change behavior with respect to overwrite_vars

awx/main/migrations/0199_inventorygroupvariableswithhistory_and_more.py

@@ -0,0 +1,32 @@
+# Generated by Django 4.2.20 on 2025-04-24 09:08
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main', '0198_alter_inventorysource_source_and_more'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='InventoryGroupVariablesWithHistory',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('variables', models.JSONField()),
+                ('group', models.ForeignKey(null=True, on_delete=django.db.models.deletion.CASCADE, related_name='inventory_group_variables', to='main.group')),
+                (
+                    'inventory',
+                    models.ForeignKey(null=True, on_delete=django.db.models.deletion.CASCADE, related_name='inventory_group_variables', to='main.inventory'),
+                ),
+            ],
+        ),
+        migrations.AddConstraint(
+            model_name='inventorygroupvariableswithhistory',
+            constraint=models.UniqueConstraint(
+                fields=('inventory', 'group'), name='unique_inventory_group', violation_error_message='Inventory/Group combination must be unique.'
+            ),
+        ),
+    ]