Patch maintenance policy

Drupal core and contributed project code sometimes needs patching to fix specific issues. The policy outlines how we deal with patches and maintain them in a variety of situations.

1.0 Where patches are defined

We currently aim to include patches in the module, project or theme that requires the project to be patched.

For example, the locacalgov profile requires drupal/core (Drupal core):

So patches for drupal/core live in the localgov profile's composer.json.

2.0 Applying patches

We crrently use the composer-patches plugin to manage patches with composer. See https://github.com/cweagans/composer-patches

This supports nesting of patches in composer.json files of projects that we require from the main composer.json file or our project.

This may change.

3.0 Testing patches

To test a pull request with changes to patches, we sometimes need to run a composer require with an alias, to require a dev branch while pretending to composer we are on a recent tagged release.

For example, here's a historical change to a patch in the localgov profile.

This is a merge request from the 'fix/redirect-1.10-patch' branch.

To test this branch, from the composer root of our LocalGov Drupal project, we can run.

composer require "localgovdrupal/localgov:dev-fix/redirect-1.10-patch as 3.0.10" -W

This will fetch the fix/redirect-1.10-patch branch but alias it as 3.0.10, the current latest release of the localgov profile.

4.0 Patching major versions of Drupal core

Sometimes we have a patch required for one version of Drupal that is not needed for a more recent version.

In this case, we aim to maintain the patch for currently supported versions of Drupal core and use patches-ignore in our composer root composer.json.

For example, the 2.1.3 release of localgov/localgov_services includes a patch for Drupal core.

"patches": {
    "drupal/core": {
        "node_access filters out accessible nodes when node is left joined (1349080)": "https://git.drupalcode.org/project/drupal/-/commit/c271adb.diff"
    }
}

This is needed for Druapl 9, but not needed for Drupal 10. However localgov_services still supports both Drupal 9 and 10.

To work around this, we keep the patch in localgov_services for now, and tell composer to ignore it in our root composer.json like this:

"patches-ignore": {
    "localgovdrupal/localgov_services": {
        "drupal/core": {
            "node_access filters out accessible nodes when node is left joined (1349080)" : "https://git.drupalcode.org/project/drupal/-/commit/c271adb.diff"
        }
    }
},

See https://github.com/localgovdrupal/localgov_project/blob/3.1.1/composer.json#L71-L77

It is important to note that the localgovdrupal/localgov_project composer file is meant as both a starting point and a reference for ongoing LocalGov Drupal codebases. Most people will use this as a starting point and evolve and maintain their own root composer.json file as the project evolves.

As far as we know, patches-ignore only works in the root composer.json file.