Django migration linter

Detect backward incompatible migrations for your django project. It will save you time by making sure migrations will not break anything.

Installation

pip install django-migration-linter

Usage

django-migration-linter DJANGO_PROJECT_FOLDER [GIT_COMMIT_ID] [--ignore-name-contains=IGNORE_NAME_CONTAINS] [--include-apps INCLUDE_APPS [INCLUDE_APPS ...] | --exclude-apps EXCLUDE_APPS [EXCLUDE_APPS ...]]

Parameter	Description
DJANGO_PROJECT_FOLDER	An absolute or relative path to the django project.
GIT_COMMIT_ID	If specified, only migrations since this commit will be taken into account. If not specified, all migrations will be linted.
--ignore-name-contains IGNORE_NAME_CONTAINS	Ignore migrations containing this name.
--ignore-name IGNORE_NAME [IGNORE_NAME ...]	Ignore migrations with exactly one of these names.
--include-apps INCLUDE_APPS [INCLUDE_APPS ...]	Check only migrations that are in the specified django apps.
--exclude-apps EXCLUDE_APPS [EXCLUDE_APPS ...]	Ignore migrations that are in the specified django apps.
--verbose or -v	Print more information during execution.
--database DATABASE	Specify the database for which to generate the SQL. Defaults to default.
--cache-path PATH	specify a directory that should be used to store cache-files in.
--no-cache	Don't use a cache.

Examples

3YOURMIND is running the linter on every build getting pushed through CI. Checkout the examples/ folder to see how you could integrate the linter in your test suite.

Backward incompatible migrations

The linter analyses your migrations and checks the SQL for:

• Added NOT NULL columns, which don't have a DEFAULT value
• Dropping columns
• Renaming columns
• Renaming tables
• Altering columns (which can be backward compatible and eventually ignored)

Those are the most important and frequent backward incompatible migrations. We are happy to add more if you have some.

Ignoring migrations

You can also ignore migrations by adding this to your migrations:

import django_migration_linter as linter
# ...

    operations = [
        linter.IgnoreMigration(),
        # ...
    ]
# ...

Cache

By default, the linter uses a cache to prevent linting the same migration again. The default location of the cache on Linux is /home/<username>/.cache/django-migration-linter/<version>/<ldjango-project>.pickle.

Since the linter uses hashes, modifying migration files, will re-run the linter on that migration. If you want to run the linter without cache, use the flag --no-cache. If you want to invalidate the cache, delete the cache folder.

Tests

The easiest way to run the tests is to invoke tox.

Contributing

First, thank you very much if you want to contribute to the project. Please base your work on the master branch and also target this branch in your pull request.

Blog post

Keeping Django database migrations backward compatible

License

django-migration-linter is released under the Apache 2.0 License.