#26624: Error when running sqlmigrate after dropping index (of index_together)
without actually migrating
----------------------------------+--------------------------------------
Reporter: akki | Owner: <default>
Type: Bug | Status: new
Component: Migrations | Version: master
Severity: Normal | Resolution:
Keywords: sqlmigrate index | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
----------------------------------+--------------------------------------
Changes (by akki):
* needs_docs: => 0
* needs_tests: => 0
* needs_better_patch: => 0
Old description:
> I get an error when I run `sqlmigrate` for a migration which drops an
> `index_together` constraint until actually migrating the previous
> migration.
>
> Steps to reproduce the bug:
>
> 1) Create app with the following models:
> {{{
> #!python
> from django.db import models
>
> class Brand(models.Model):
> name = models.CharField(max_length=100, db_index=True)
> value = models.IntegerField(blank=True, null=True, default=0)
>
> class Meta:
> index_together = (
> ('name', 'value'),
> )
> }}}
>
> Run `python manage.py makemigrations`.
> Then see the sql statements using `python manage.py sqlmigrate <app_name>
> 0001_initial`.
> Everything works fine.
>
> 2) Remove the `index_together` part (and the whole `Meta` class).
>
> Now run `python manage.py makemigrations`.
> Then see the sql statements using `python manage.py sqlmigrate <app_name>
> <migration_name>` and an error is thrown.
>
> {{{
>
> Traceback (most recent call last):
> File "manage.py", line 22, in <module>
> execute_from_command_line(sys.argv)
> File "d:\git\django\django\core\management\__init__.py", line 367, in
> execute_from_command_line
> utility.execute()
> File "d:\git\django\django\core\management\__init__.py", line 359, in
> execute
> self.fetch_command(subcommand).run_from_argv(self.argv)
> File "d:\git\django\django\core\management\base.py", line 305, in
> run_from_argv
> self.execute(*args, **cmd_options)
> File "d:\git\django\django\core\management\commands\sqlmigrate.py",
> line 33, in execute
> return super(Command, self).execute(*args, **options)
> File "d:\git\django\django\core\management\base.py", line 356, in
> execute
> output = self.handle(*args, **options)
> File "d:\git\django\django\core\management\commands\sqlmigrate.py",
> line 62, in handle
> sql_statements = executor.collect_sql(plan)
> File "d:\git\django\django\db\migrations\executor.py", line 177, in
> collect_sql
> state = migration.apply(state, schema_editor, collect_sql=True)
> File "d:\git\django\django\db\migrations\migration.py", line 129, in
> apply
> operation.database_forwards(self.app_label, schema_editor, old_state,
> project_state)
> File "d:\git\django\django\db\migrations\operations\models.py", line
> 557, in database_forwards
> getattr(new_model._meta, self.option_name, set()),
> File "d:\git\django\django\db\backends\base\schema.py", line 345, in
> alter_index_together
> self._delete_composed_index(model, fields, {'index': True},
> self.sql_delete_index)
> File "d:\git\django\django\db\backends\base\schema.py", line 358, in
> _delete_composed_index
> ", ".join(columns),
> ValueError: Found wrong number (0) of constraints for ert_brand(name,
> value)
> }}}
>
> But the problem gets rectified if we migrate the first migration (i.e.
> 0001_initial in this case).
New description:
I get an error when I run `sqlmigrate` for a migration which drops an
`index_together` constraint until actually migrating the previous
migration. It happens for postgres and not for sqlite.
Steps to reproduce the bug:
1) Create app with the following models:
{{{
#!python
from django.db import models
class Brand(models.Model):
name = models.CharField(max_length=100, db_index=True)
value = models.IntegerField(blank=True, null=True, default=0)
class Meta:
index_together = (
('name', 'value'),
)
}}}
Run `python manage.py makemigrations`.
Then see the sql statements using `python manage.py sqlmigrate <app_name>
0001_initial`.
Everything works fine.
2) Remove the `index_together` part (and the whole `Meta` class).
Now run `python manage.py makemigrations`.
Then see the sql statements using `python manage.py sqlmigrate <app_name>
<migration_name>` and an error is thrown.
{{{
Traceback (most recent call last):
File "manage.py", line 22, in <module>
execute_from_command_line(sys.argv)
File "d:\git\django\django\core\management\__init__.py", line 367, in
execute_from_command_line
utility.execute()
File "d:\git\django\django\core\management\__init__.py", line 359, in
execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "d:\git\django\django\core\management\base.py", line 305, in
run_from_argv
self.execute(*args, **cmd_options)
File "d:\git\django\django\core\management\commands\sqlmigrate.py", line
33, in execute
return super(Command, self).execute(*args, **options)
File "d:\git\django\django\core\management\base.py", line 356, in
execute
output = self.handle(*args, **options)
File "d:\git\django\django\core\management\commands\sqlmigrate.py", line
62, in handle
sql_statements = executor.collect_sql(plan)
File "d:\git\django\django\db\migrations\executor.py", line 177, in
collect_sql
state = migration.apply(state, schema_editor, collect_sql=True)
File "d:\git\django\django\db\migrations\migration.py", line 129, in
apply
operation.database_forwards(self.app_label, schema_editor, old_state,
project_state)
File "d:\git\django\django\db\migrations\operations\models.py", line
557, in database_forwards
getattr(new_model._meta, self.option_name, set()),
File "d:\git\django\django\db\backends\base\schema.py", line 345, in
alter_index_together
self._delete_composed_index(model, fields, {'index': True},
self.sql_delete_index)
File "d:\git\django\django\db\backends\base\schema.py", line 358, in
_delete_composed_index
", ".join(columns),
ValueError: Found wrong number (0) of constraints for ert_brand(name,
value)
}}}
But the problem gets rectified if we migrate the first migration (i.e.
0001_initial in this case).
--
--
Ticket URL: <https://code.djangoproject.com/ticket/26624#comment:1>
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