Stop caching plugin discovery/info hooks by language

Just trying to see what happens...

So this worked, the only test fails are broken unit tests that expect calls to the language manager...

So. many. plugin. managers.

We still need a by-language cache for yaml and I also kept it for the config mapper stuff, which only uses an info hook.

Re-roll and fixing the test fail.

Nice job, looks great.

Thanks, but...

Also not sure if there's something else we can clean up based on @catch statements...

Yes, that I know, except the ones that now still need them because they manually add the langcode to the cache key, but most of them already had one, with the exception of the contextual links manager.

So what is left here? Not clear to me. Looks like catch's steps from the issue summary are done then? :)

A change record :)

Added draft change notice at https://drupal.org/node/2284277. While doing that, found the following:

+++ b/core/lib/Drupal/Core/Validation/ConstraintManager.php
@@ -41,16 +40,15 @@ class ConstraintManager extends DefaultPluginManager {
+    // @todo static discovery still uses t(), change to TranslationWrapper?
+    $this->setCacheBackend($cache_backend, 'validation_constraint_plugins');

So this will be a bug then when this is committed? It will not cache by language but will be language specific? Not sure we want to do this?! At least we need to add an issue URL in the @todo.

Wrote this for the change notice but not sure if this can be considered a bug as well, sounds like it will make plugin cache clearing for the few plugin managers that cache by language (see my list on the change notice if I identified them right):

Finally, DefaultPluginManager::clearCachedDefinitions() does not remove all cached variants for all languages but only the one cached for the specific language being used at the time.

Fixed the @todo, updated the change record a bit and made it reference this issue.

Updated the last sentence there, not clearing all languages anymore is by design because the default plugin manager has no understanding anymore of languages. If you add that manually, the easiest way to ensure the caches are cleared is to use a cache tag which all the relevant core plugin managers are doing now.

That last interdiff looks good, sorry for the premature RTBC the first time :)

Published the change record. :)

I don't know if alter hooks were discussed when this first went in, but #2509180: [meta] Various plugin definition alter() hooks incorrectly document to use t() is for doing so now.