Inconsistency error after unapplying squash migration.

[Shehzad-Ahmed]

Just for reminder: Migrations contain parent migrations called dependencies. So when an parent migration is rolled back all of its successors are also rolled back. For the consistency django make record of all applied and rolled back(unapplied) migrations. Now before any new migration is applied consistency is checked.

Just for reminder: In Case when a squash migration is created, a list inside it is maintained which tracks all migrations it replaced called replaces.

Problem: when a squash migration is rolled back all its replaces(which can be dependencies or depended on other migrations) are marked UN-applied but squash migration migration it-self does not record UN-applied. Since the operation of rolling back squash migration becomes completed. But Then when new migrate operation is performed, it causes inconsistency error e.g below:

"django.db.migrations.exceptions.InconsistentMigrationHistory: Migration compliance.0007_auto_20180329_1238_squashed_0026_auto_20180815_0741 is applied before its dependency survey.0092_prospectfarmerviewlinkcompliancelink on database 'default' ."

[Carlton Gibson]

Hi. Thanks for the report. Are you able to put together a small sample project demonstrating this?

[Simon Charette]

​PR

[Simon Charette]

Or at least tests to demonstrate the issue.

[Carlton Gibson]

OK, I can't reproduce this with the information provided.

In my testing all combinations of migrate, showmigrations, squashmigrations and so on are behaving as expected.

Happy to look at a sample project demonstrating an issue, but short of that I'm not sure we can say anything.