Data migration for the Build model

InvenTree/build/migrations/0032_auto_20211014_0632.py

@@ -0,0 +1,57 @@
+# Generated by Django 3.2.5 on 2021-10-14 06:32
+
+import re
+
+from django.db import migrations
+
+
+def build_refs(apps, schema_editor):
+    """
+    Rebuild the integer "reference fields" for existing Build objects
+    """
+
+    print("\n - Rebuilding reference field for BuildOrder model...")
+
+    BuildOrder = apps.get_model('build', 'build')
+
+    n = BuildOrder.objects.count()
+
+    for build in BuildOrder.objects.all():
+
+        ref = 0
+
+        result = re.match(r"^(\d+)", build.reference)
+
+        if result and len(result.groups()) == 1:
+            try:
+                ref = int(result.groups()[0])
+            except:
+                ref = 0
+
+        build.reference_int = ref
+        build.save()
+
+    print(f" - Updated {n} BuildOrder objects")
+    print(f" - COMPLETE! -")
+
+def unbuild_refs(apps, schema_editor):
+    """
+    Provided only for reverse migration compatibility
+    """
+    pass
+
+
+class Migration(migrations.Migration):
+
+    atomic = False
+
+    dependencies = [
+        ('build', '0031_build_reference_int'),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            build_refs,
+            reverse_code=unbuild_refs
+        )
+    ]