Scenarios in DF should apply to all extensions (install profile, theme and module)

[saltednut]

One great thing is that all extensions can install configuration via config/install - it stands to reason that if that is the case, any extension could call itself a Scenario.

The Scenarios module used in DF could listen for a key event to enable scenarios. Right now its demo content import is "listening" for only the profile installation occurrence via a hook we have added (and not successfully committed yet) to core. Invoke hook after a site install is complete

This works and we could add hooks or even events/listeners for module, theme and profile install occurrences. That might be the best, most stable, long term solution.

However, I have another idea that one could do with core in its current state that will help Modules and Themes declare themselves a scenario and act accordingly. We'd do this by defining a scenario yml file similar to the ACF catalogs like the one found here: https://github.com/acquia/acf/blob/master/acf_demo/modules/acf_demo_api/config/install/acf_catalog.catalog.acf_demo.yml - the scenarios module would listen for a config install and only act when a new "scenario" config popped in with info about things like where to find a CDF to import or what migrations need run.

The one issue with using config is that this doesn't really help install profiles. They will still likely be better off with a hook or an event listener that ensures everything they need installed is there before running the scenario enablement.

Otherwise the other ways we can ensure this will work is if:

1. All the really critical config is in the CDF so that's mostly imported for us.
2. A theme/module that used this config based scenario assumes it might fire the "content dump" at a random time while config is being imported even if all the views haven't landed yet
3. As such (re: 2) they should only ship with limited config
4. We really ought to try to get some better events in core around the extension system because this will mostly work but have hiccups and (again) doesn't really work for install profiles that have lots and lots of config and module dependencies.

[saltednut]

Just remembered that there is an event for Modules Installed otherwise config_rewrite wouldn't even work. Oof! I wrote something similar to this 2 years ago. https://git.drupalcode.org/project/config_rewrite/blob/8.x-2.x/src/EventSubscriber/ConfigRewriteInstallSubscriber.php#L34

[saltednut]

Gosh its all flooding back to me now I remember. Sam and I worked on a 2.x branch of config_rewrite that used this patch https://www.drupal.org/project/drupal/issues/2350111 - the eventsubscriber stuff is there. In 1.x we use a hook called hook_module_preinstall() -- in order to make this work with modules asap, we could use hook_module_preinstall() but sadly there's no theme equivalent to this hook that I can find.

[saltednut]

Ok actually here's the theme hook, I think? https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Render%21theme.api.php/function/hook_themes_installed/8.7.x

Example from shortcut should help, https://api.drupal.org/api/drupal/core%21modules%21shortcut%21shortcut.module/function/shortcut_themes_installed/8.7.x

[saltednut]

So to recap:

Right now we'll implement hook_module_preinstall() and hook_themes_installed() to add this functionality to the existing functionality similar to what we do for install profiles here: https://git.drupalcode.org/project/scenarios/blob/8.x-4.x/scenarios.module#L58

Only difference being we'd feed a module name or theme name in.

In the future, we'd like to move over to a system where all extensions fire the same event when they get enabled and scenarios should use an event subscriber consistently across all types of extensions.

[saltednut]

hook_modules_installed was a better call, but hook_themes_installed was the way to go here, see https://git.drupalcode.org/project/scenarios/commit/4daf46ca47f3ebd26ca4fa44f5d0de06fffad0df