#34881: Model-rename migration fails with IntegrityError if m2m relations to
self
exist
----------------------------+--------------------------------------
Reporter: dennisvang | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: dev
Severity: Normal | Resolution:
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
----------------------------+--------------------------------------
Changes (by Natalia Bidart):
* cc: Simon Charette, Mariusz Felisiak (added)
* version: 4.2 => dev
* component: Uncategorized => Migrations
Comment:
Assuming a simpler model for `Person` where the M2M is implicit, and doing
the rename, does indeed work. The SQL for the migration is:
* 0003 (renamed `SimplerPerson` to `SimplerPersonFoo`)
{{{#!sql
BEGIN;
--
-- Rename model SimplerPerson to SimplerPersonFoo
--
ALTER TABLE "ticket_34881_simplerperson" RENAME TO
"ticket_34881_simplerpersonfoo";
CREATE TABLE "ticket_34881_simplerpersonfoo_parents_or_children" ("id"
integer NOT NULL PRIMARY KEY AUTOINCREMENT, "from_simplerpersonfoo_id"
bigint NOT NULL REFERENCES "ticket_34881_simplerpersonfoo" ("id")
DEFERRABLE INITIALLY DEFERRED, "to_simplerpersonfoo_id" bigint NOT NULL
REFERENCES "ticket_34881_simplerpersonfoo" ("id") DEFERRABLE INITIALLY
DEFERRED);
INSERT INTO "ticket_34881_simplerpersonfoo_parents_or_children" (id,
from_simplerpersonfoo_id, to_simplerpersonfoo_id) SELECT id,
from_simplerperson_id, to_simplerperson_id FROM
"ticket_34881_simplerperson_parents_or_children";
DROP TABLE "ticket_34881_simplerperson_parents_or_children";
CREATE UNIQUE INDEX
"ticket_34881_simplerpersonfoo_parents_or_children_from_simplerpersonfoo_id_to_simplerpersonfoo_id_f05f0b12_uniq"
ON "ticket_34881_simplerpersonfoo_parents_or_children"
("from_simplerpersonfoo_id", "to_simplerpersonfoo_id");
CREATE INDEX
"ticket_34881_simplerpersonfoo_parents_or_children_from_simplerpersonfoo_id_6d3cdfb4"
ON "ticket_34881_simplerpersonfoo_parents_or_children"
("from_simplerpersonfoo_id");
CREATE INDEX
"ticket_34881_simplerpersonfoo_parents_or_children_to_simplerpersonfoo_id_83aff647"
ON "ticket_34881_simplerpersonfoo_parents_or_children"
("to_simplerpersonfoo_id");
COMMIT;
}}}
It's worth noting that the content of the explicit M2M (`Relation`) has
these rows:
{{{
sqlite> SELECT * FROM ticket_34881_relation;
1|1|3
2|2|3
3|1|4
4|2|4
}}}
While the rows for the implicit one include:
{{{
sqlite> SELECT * FROM ticket_34881_simplerperson_parents_or_children;
1|3|1
2|3|2
3|1|3
4|2|3
5|4|1
6|4|2
7|1|4
8|2|4
}}}
It may look like a valid issue but I'll cc Simon and Mariusz for a second
opinion.
--
Ticket URL: <https://code.djangoproject.com/ticket/34881#comment:10>
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