Fixed dataset_repo migration

CHANGELOG.md

@@ -39,6 +39,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Incorrect work when copy job list with "Copy" button (<https://github.com/openvinotoolkit/cvat/pull/3749>)
 - Iterating over manifest (<https://github.com/openvinotoolkit/cvat/pull/3792>)
 - Manifest removing (<https://github.com/openvinotoolkit/cvat/pull/3791>)
+- Migration of `dataset_repo` application (<https://github.com/openvinotoolkit/cvat/pull/3827>)
 
 ### Security
 

cvat/apps/dataset_repo/migrations/0006_gitdata_format.py

@@ -1,19 +1,25 @@
-# Generated by Django 2.1.3 on 2019-02-05 17:08
+# Generated by Django 3.1.13 on 2021-10-26 10:10
 
 from django.db import migrations, models
 
 
+def update_default_format_field(apps, schema_editor):
+    GitData = apps.get_model('dataset_repo', 'GitData')
+    for git_data in GitData.objects.all():
+        if not git_data.format:
+            git_data.format = 'CVAT for images 1.1' if git_data.task.mode == 'annotation' else 'CVAT for video 1.1'
+            git_data.save()
 class Migration(migrations.Migration):
+
     dependencies = [
         ('dataset_repo', '0005_auto_20201019_1100'),
     ]
 
-    replaces = [('git', '0006_gitdata_format')]
-
     operations = [
         migrations.AddField(
             model_name='gitdata',
             name='format',
-            field=models.CharField(max_length=256)
+            field=models.CharField(blank=True, max_length=256),
         ),
+        migrations.RunPython(update_default_format_field),
     ]

cvat/apps/dataset_repo/models.py

@@ -20,7 +20,7 @@ class GitData(models.Model):
     task = models.OneToOneField(Task, on_delete = models.CASCADE, primary_key = True)
     url = models.URLField(max_length = 2000)
     path = models.CharField(max_length=256)
-    format = models.CharField(max_length=256)
+    format = models.CharField(max_length=256, blank=True)
     sync_date = models.DateTimeField(auto_now_add=True)
     status = models.CharField(max_length=20, default=GitStatusChoice.NON_SYNCED)
     lfs = models.BooleanField(default=True)