On 03/08/2016 03:54 PM, Stephen Finucane wrote:
At the moment a patch is split into two model entries: a Patch and a
linked Comment. The original rationale for this was that a Patch is
really a sub-class of Comment. A comment is a record of the text
content of an incoming mail, while a patch is that, plus the patch
content too. Hence the separation and a one-to-one relationship when a
patch is present. However, this decision was made before Django added
support for model inheritance and is no longer necessary. This change
flatten the models in preparation for some email subclassing work. This
is achieved by copying over the non-duplicated fields from the Comment
to the linked Patch, then deleting the Comment.
The migrations are broken into two steps: a schema migration and a data
migration, per the recommendations of the Django documentation [1]. SQL
migration scripts, where necessary, will need to be created manually as
there appears to be no way to do this in a way that is
RDBMS-independant [2][3].
[1] https://docs.djangoproject.com/en/1.9/topics/migrations/#data-migrations
[2] https://stackoverflow.com/q/6856849/
[3] https://stackoverflow.com/q/224732/
Signed-off-by: Stephen Finucane <[email protected]>
Reviewed-by: Andy Doan <[email protected]>
diff --git a/patchwork/migrations/0007_move_comment_content_to_patch_content.py
b/patchwork/migrations/0007_move_comment_content_to_patch_content.py
+from django.db import migrations, models
Hate to nitpick over migration warnings since they are usually machine
generated, but "models" is an unused import for this module.
+def copy_comment_field(apps, schema_editor):
+ Comment = apps.get_model('patchwork', 'Comment')
+ Patch = apps.get_model('patchwork', 'Patch')
+
+ for patch in Patch.objects.all():
+ # this can only return one entry due to the unique_together
+ # constraint
+ comment = Comment.objects.get(patch=patch, msgid=patch.msgid)
+ patch.content = comment.content
+ patch.save()
This should work based on the normal flow of patchwork. However, I've
found a place where instance can't complete this migration. We've added
some hacks to track AOSP contributions[1]. We don't actually create a
comment linked to the patch, we just use the "content" field to point to
the AOSP change. I *think* if you changed this to
Comment.objects.filter(....) and if count() == 1 it wouldn't break my
instance. However, I'm not sure that's fair to ask you to add baggage to
deal with me when its probably possible for me to add an internal
migration to "fix" our AOSP stuff. Thought it would hurt to ask though.
1: http://patches.linaro.org/patch/7669/
-andy
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