Implement DB migrations for allowing changing of the culprit feature (#8295)

treeherder/perf/migrations/0056_performancealertsummary_original_push.py

@@ -0,0 +1,33 @@
+# Generated by Django 5.1.3 on 2024-11-14 13:30
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+def update_summary_original_push(apps, schema_editor):
+    PerformanceAlertSummary = apps.get_model('perf', 'PerformanceAlertSummary')
+    for alert in PerformanceAlertSummary.objects.all():
+        alert.original_push = alert.push
+        alert.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("perf", "0055_remove_performancealerttesting_related_summary_and_more"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="performancealertsummary",
+            name="original_push",
+            field=models.ForeignKey(
+                default=None,
+                null=True,
+                on_delete=django.db.models.deletion.CASCADE,
+                related_name="+",
+                to="model.push",
+            ),
+        ),
+        migrations.RunPython(update_summary_original_push, reverse_code=migrations.RunPython.noop),
+    ]

treeherder/perf/models.py

@@ -272,7 +272,9 @@ class PerformanceAlertSummary(models.Model):
 
     prev_push = models.ForeignKey(Push, on_delete=models.CASCADE, related_name="+")
     push = models.ForeignKey(Push, on_delete=models.CASCADE, related_name="+")
-
+    original_push = models.ForeignKey(
+        Push, on_delete=models.CASCADE, related_name="+", null=True, default=None
+    )
     manually_created = models.BooleanField(default=False)
 
     notes = models.TextField(null=True, blank=True)
@@ -344,6 +346,9 @@ class PerformanceAlertSummary(models.Model):
             if update_fields is not None:
                 update_fields = {"bug_due_date"}.union(update_fields)
 
+        if not self.original_push:
+            self.original_push = self.push
+
         super().save(*args, update_fields=update_fields, **kwargs)
         self.__prev_bug_number = self.bug_number