id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
35199	Makemigrations raises KeyError when removing a field from Meta.unique_together when its a list	Paco Martínez	nobody	"Having a model like this, with a **unique_together** with a **list of lists**:

{{{
from django.db import models

class MyModel(models.Model):
    field1 = models.CharField(max_length=50)
    field2 = models.ForeignKey()
    field3 = models.ForeignKey()

    class Meta:
        unique_together=[['field1', 'field2', 'field3']]
}}}


If we want to remove one of the fields from the constraint like:

{{{
    class Meta:
        unique_together=[['field1', 'field2']]
}}}

When we run the ''makemigrations'' command, it raises a KeyError. This is the traceback:
{{{
Traceback (most recent call last):
  File ""/code/manage.py"", line 26, in <module>
    main()
  File ""/code/manage.py"", line 22, in main
    execute_from_command_line(sys.argv)
  File ""/usr/local/lib/python3.12/site-packages/django/core/management/__init__.py"", line 442, in execute_from_command_line
    utility.execute()
  File ""/usr/local/lib/python3.12/site-packages/django/core/management/__init__.py"", line 436, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File ""/usr/local/lib/python3.12/site-packages/django/core/management/base.py"", line 412, in run_from_argv
    self.execute(*args, **cmd_options)
  File ""/usr/local/lib/python3.12/site-packages/django/core/management/base.py"", line 458, in execute
    output = self.handle(*args, **options)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ""/usr/local/lib/python3.12/site-packages/django/core/management/base.py"", line 106, in wrapper
    res = handle_func(*args, **kwargs)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ""/usr/local/lib/python3.12/site-packages/django/core/management/commands/makemigrations.py"", line 233, in handle
    changes = autodetector.changes(
              ^^^^^^^^^^^^^^^^^^^^^
  File ""/usr/local/lib/python3.12/site-packages/django/db/migrations/autodetector.py"", line 46, in changes
    changes = self._detect_changes(convert_apps, graph)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ""/usr/local/lib/python3.12/site-packages/django/db/migrations/autodetector.py"", line 192, in _detect_changes
    self.generate_removed_altered_unique_together()
  File ""/usr/local/lib/python3.12/site-packages/django/db/migrations/autodetector.py"", line 1506, in generate_removed_altered_unique_together
    self._generate_removed_altered_foo_together(operations.AlterUniqueTogether)
  File ""/usr/local/lib/python3.12/site-packages/django/db/migrations/autodetector.py"", line 1481, in _generate_removed_altered_foo_together
    for (
  File ""/usr/local/lib/python3.12/site-packages/django/db/migrations/autodetector.py"", line 1462, in _get_altered_foo_together_operations
    field = new_model_state.get_field(field_name)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ""/usr/local/lib/python3.12/site-packages/django/db/migrations/state.py"", line 765, in get_field
    return self.fields[field_name]
           ~~~~~~~~~~~^^^^^^^^^^^^
KeyError: 'field1'

}}}

This does NOT happen when the unique_together option is a **tuple**. It works as expected creating the migration."	Bug	closed	Migrations	4.2	Normal	invalid	migrations, unique_together, makemigrations	Paco Martínez	Unreviewed	0	0	0	0	0	0