Summary

Fix index introspection on PostgreSQL 18.

Review Request #14923 — Created March 17, 2026 and submitted June 19, 2026, 11:21 a.m.

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Owner

david

Repository

Django Evolution

Branch

master

Bugs

Depends On

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django-evolution

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Description

PostgreSQL 18 stores NOT NULL constraints in pg_constraint (with
contype='n'). Django's get_constraints() includes these in its
results, but with all type flags (index, unique, primary_key, check,
foreign_key) set to False. get_constraints_for_table() was passing
through all constraint entries unconditionally, causing these NOT NULL
constraints to be tracked as regular non-unique indexes in
DatabaseState (e.g., "tests_testmodel_int_field1_not_null").

This caused two categories of failures:

ChangeField operations that modified db_index or unique would
find unexpected NOT NULL indexes in the database state, causing
assertion failures.
ChangeMeta(indexes) operations would see NOT NULL constraint
entries instead of the actual Django-managed indexes, generating
incorrect DROP/CREATE INDEX SQL.

The fix filters get_constraints_for_table() to only include entries
where index, unique, or primary_key is True. This excludes NOT NULL
constraints, check constraints, and foreign key constraint entries --
none of which should be tracked as indexes in DatabaseState. (Foreign
key fields still have their actual indexes captured via separate
index=True entries, and check constraints are handled through Django's
Meta.constraints system.)

Testing Done

Ran dbtests-minmax

Commits

Summary	ID
Fix index introspection on PostgreSQL 18. PostgreSQL 18 stores `NOT NULL` constraints in `pg_constraint` (with `contype='n'`). Django's `get_constraints()` includes these in its results, but with all type flags (index, unique, primary_key, check, foreign_key) set to False. `get_constraints_for_table()` was passing through all constraint entries unconditionally, causing these NOT NULL constraints to be tracked as regular non-unique indexes in `DatabaseState` (e.g., "tests_testmodel_int_field1_not_null"). This caused two categories of failures: 1. `ChangeField` operations that modified `db_index` or `unique` would find unexpected `NOT NULL` indexes in the database state, causing assertion failures. 2. `ChangeMeta(indexes)` operations would see `NOT NULL` constraint entries instead of the actual Django-managed indexes, generating incorrect `DROP/CREATE INDEX SQL`. The fix filters `get_constraints_for_table()` to only include entries where index, unique, or primary_key is True. This excludes NOT NULL constraints, check constraints, and foreign key constraint entries -- none of which should be tracked as indexes in DatabaseState. (Foreign key fields still have their actual indexes captured via separate `index=True` entries, and check constraints are handled through Django's `Meta.constraints` system.) Testing Done: Ran dbtests-minmax	wyzwxmuzpkxnwrpzokqqzpoosrtoznnm

Summary

Fix index introspection on PostgreSQL 18.

PostgreSQL 18 stores `NOT NULL` constraints in `pg_constraint` (with `contype='n'`). Django's `get_constraints()` includes these in its results, but with all type flags (index, unique, primary_key, check, foreign_key) set to False. `get_constraints_for_table()` was passing through all constraint entries unconditionally, causing these NOT NULL constraints to be tracked as regular non-unique indexes in `DatabaseState` (e.g., "tests_testmodel_int_field1_not_null"). This caused two categories of failures: 1. `ChangeField` operations that modified `db_index` or `unique` would find unexpected `NOT NULL` indexes in the database state, causing assertion failures. 2. `ChangeMeta(indexes)` operations would see `NOT NULL` constraint entries instead of the actual Django-managed indexes, generating incorrect `DROP/CREATE INDEX SQL`. The fix filters `get_constraints_for_table()` to only include entries where index, unique, or primary_key is True. This excludes NOT NULL constraints, check constraints, and foreign key constraint entries -- none of which should be tracked as indexes in DatabaseState. (Foreign key fields still have their actual indexes captured via separate `index=True` entries, and check constraints are handled through Django's `Meta.constraints` system.) Testing Done: Ran dbtests-minmax

wyzwxmuzpkxnwrpzokqqzpoosrtoznnm

Issues

Description	From	Last Updated
We're ultimately going to want to look up other details on constraints, so I think this method is most helpful …	chipx86	June 4, 2026, 3:28 p.m.
This will need unit tests for DatabaseState.rescan_tables with the different types of checks, and the ChangeField and ChangeMeta failures.	chipx86	June 4, 2026, 3:28 p.m.

flake8 passed.

JSHint passed.

The issue has been resolved. Show all issues

We're ultimately going to want to look up other details on constraints, so I think this method is most helpful as an unfiltered wrapper around introspection.get_constraints() (even once the legacy DB implementation is removed, this takes care of cursor setup and normalization).

I think the approach I'd prefer here is to include the other fields we need in the results, and then filter at the call site that handles indexing. That keeps the filtering where it's needed and frees us up to perform lookups for things like Check Constraints and primary key lookup later.

The issue has been resolved. Show all issues

This will need unit tests for DatabaseState.rescan_tables with the different types of checks, and the ChangeField and ChangeMeta failures.

Commits:

	Summary	ID
	Fix index introspection on PostgreSQL 18. PostgreSQL 18 stores `NOT NULL` constraints in `pg_constraint` (with `contype='n'`). Django's `get_constraints()` includes these in its results, but with all type flags (index, unique, primary_key, check, foreign_key) set to False. `get_constraints_for_table()` was passing through all constraint entries unconditionally, causing these NOT NULL constraints to be tracked as regular non-unique indexes in `DatabaseState` (e.g., "tests_testmodel_int_field1_not_null"). This caused two categories of failures: 1. `ChangeField` operations that modified `db_index` or `unique` would find unexpected `NOT NULL` indexes in the database state, causing assertion failures. 2. `ChangeMeta(indexes)` operations would see `NOT NULL` constraint entries instead of the actual Django-managed indexes, generating incorrect `DROP/CREATE INDEX SQL`. The fix filters `get_constraints_for_table()` to only include entries where index, unique, or primary_key is True. This excludes NOT NULL constraints, check constraints, and foreign key constraint entries -- none of which should be tracked as indexes in DatabaseState. (Foreign key fields still have their actual indexes captured via separate `index=True` entries, and check constraints are handled through Django's `Meta.constraints` system.) Testing Done: Ran dbtests-minmax	wyzwxmuzpkxnwrpzokqqzpoosrtoznnm
	Fix index introspection on PostgreSQL 18. PostgreSQL 18 stores `NOT NULL` constraints in `pg_constraint` (with `contype='n'`). Django's `get_constraints()` includes these in its results, but with all type flags (index, unique, primary_key, check, foreign_key) set to False. `get_constraints_for_table()` was passing through all constraint entries unconditionally, causing these NOT NULL constraints to be tracked as regular non-unique indexes in `DatabaseState` (e.g., "tests_testmodel_int_field1_not_null"). This caused two categories of failures: 1. `ChangeField` operations that modified `db_index` or `unique` would find unexpected `NOT NULL` indexes in the database state, causing assertion failures. 2. `ChangeMeta(indexes)` operations would see `NOT NULL` constraint entries instead of the actual Django-managed indexes, generating incorrect `DROP/CREATE INDEX SQL`. The fix filters `get_constraints_for_table()` to only include entries where index, unique, or primary_key is True. This excludes NOT NULL constraints, check constraints, and foreign key constraint entries -- none of which should be tracked as indexes in DatabaseState. (Foreign key fields still have their actual indexes captured via separate `index=True` entries, and check constraints are handled through Django's `Meta.constraints` system.) Testing Done: Ran dbtests-minmax	wyzwxmuzpkxnwrpzokqqzpoosrtoznnm

Diff:

Revision 2 (+538 -14)

Show changes

	django_evolution/db/common.py
	django_evolution/db/state.py
	django_evolution/tests/test_change_field.py
	django_evolution/tests/test_change_meta.py
	django_evolution/tests/test_database_state.py

Checks run (2 succeeded)

flake8 passed.

JSHint passed.

Ship it!

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Status:: Completed
Change Summary:: Pushed to release-3.x (128a72d)