[1.7.x] Fixed #22293 -- Avoided renaming many-to-many tables to themselves.

Fixed this for both implementations of _alter_many_to_many, instead of
in `alter_db_table` itself (more implementations).

Backport of 1edfa155e3 from master
This commit is contained in:
Daniel Hahler 2014-03-20 05:08:28 +01:00 committed by Tim Graham
parent 345281b880
commit 21eaad68e6
3 changed files with 14 additions and 1 deletions

View File

@ -762,7 +762,8 @@ class BaseDatabaseSchemaEditor(object):
Alters M2Ms to repoint their to= endpoints.
"""
# Rename the through table
self.alter_db_table(old_field.rel.through, old_field.rel.through._meta.db_table, new_field.rel.through._meta.db_table)
if old_field.rel.through._meta.db_table != new_field.rel.through._meta.db_table:
self.alter_db_table(old_field.rel.through, old_field.rel.through._meta.db_table, new_field.rel.through._meta.db_table)
# Repoint the FK to the other side
self.alter_field(
new_field.rel.through,

View File

@ -161,6 +161,9 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
"""
Alters M2Ms to repoint their to= endpoints.
"""
if old_field.rel.through == new_field.rel.through:
return
# Make a new through table
self.create_model(new_field.rel.through)
# Copy the data across

View File

@ -347,6 +347,15 @@ class SchemaTests(TransactionTestCase):
# Ensure there is now an m2m table there
columns = self.column_classes(new_field.rel.through)
self.assertEqual(columns['tagm2mtest_id'][0], "IntegerField")
# "Alter" the field. This should not rename the DB table to itself.
with connection.schema_editor() as editor:
editor.alter_field(
Author,
new_field,
new_field,
)
# Remove the M2M table again
with connection.schema_editor() as editor:
editor.remove_field(