Deprecate migrate_drupal source plugins

Alternative proposal in !12617 which deprecates DrupalSqlBase but then skips the deprecation notices for core extensions of that class; any other extensions in contrib will trigger the message as normal.

Added some test coverage by removing test modules from the skip, and then expecting the deprecation in tests that use them. Let's see if anything else will fail now I copied in the other two source plugin deprecations from the original MR.

Added similar dynamic migration messages for the EmptySource plugin and I18nQueryTrait trait and skipped the core implementations of them, they should still trigger in contrib/custom code.

I like that, it’s pretty slick and much fewer lines than I was expecting to have to deal with. I’m inclined to try to get this merged in early in the 10.3 cycle so that contrib has time to deal with the fallout. It leaves the ‘hard’ problem of identifying each of the source plugins the legacy tests for the actual removal when the 12.x branch opens, but at least we don’t have to do that twice, once for @legacy annotations, and again for removal. And when we get around to doing it, we could just remove the suppressions to get a list of all affected tests easily enough.

@longwave, Do we need to add the @deprecated annotation for DrupalSqlBase, or should that just be covered with the deprecation of the whole module eventually?

We can, because that will notify people via PHPStan as well as via tests or at runtime - but I suspect the PHPStan baseline will grow quite a bit. Don't think we can engineer an ignore in the same way because the string will be fixed in the docblock and so it will be ignored by downstream too.

I'm inclined to do it, since we can generate the baseline and don't have to put it together manually, but it's ultimately up to the committers and RMs. Contrib and custom code will be far more likely to be alerted through phpstan, as contrib and custom test coverage is likely to be spotty at best.

Let's try out adding the annotation and seeing what the impact is. If we have to add a bunch of stuff to the baseline, so be it; perhaps we can figure a way of ignoring it for core only, but letting downstream users get their notifications.

+1 on adding the deprecation directly on DrupalSqlBase

Back to NR

I also took a hand at writing the CR for this.

The Needs Review Queue Bot tested this issue. It no longer applies to Drupal core. Therefore, this issue status is now "Needs work".

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Seems like a good deprecation to me. Couldn't find other examples of trait deprecations but the wording seemed fine and CR seems cleared so believe this one is good.

The test changes will need to use phpunit attributes instead of @group legacy now.

Back to RTBC for me

The Needs Review Queue Bot tested this issue. It no longer applies to Drupal core. Therefore, this issue status is now "Needs work".

This does not mean that the patch necessarily needs to be re-rolled or the MR rebased. Read the Issue Summary, the issue tags and the latest discussion here to determine what needs to be done.

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Looks like there's at least one more merge conflict.

Thanks for all the rebasing. Committed/pushed to 11.x so it doesn't have to be done again!