Installer - Use Riverlea's Minetta by default - #31985

🤖 Thank you for contributing to CiviCRM! ❤️ We will need to test and review this PR. 👷

➡️ Online demo of this PR 🔗

I can see the expediency of this.

But it feels like its "set Minetta as the theme" rather than "make Minetta the default". And it will force everyone to an explicit setting, and I have a sense retaining some distinction between folks on the implicit default for the setting vs people who have explicit chosen a value.

Possible third way: #31986

@ufundo Step back and consider the general architecture of Civi and Riverlea. Civi is deployed in many environments (CMS's, standalone, frontend/backend, etc). Riverlea is a base-theme with a library of sub-themes, and it's bundled-in. What's the point of bundling-in an entire library of themes? (Clearly, 3 themes is more work than 1 theme!)

Well, different themes work better in different cases. Prime example: the typical UIs in WordPress, Drupal, and Joomla look different. (The ideal default for WP-admin differs from the ideal default for Joomla-admin.) In the end-game, we're juggling multiple recommendations.

The ultimate default requires logic, which could be in a few different places:

• That logic could be runtime logic. (The current theme_xxx=default accommodates that -- you can reinterpret default in subjective ways.)
  • Of course, as you astutely pointed out, we've never had the gumption to actually change the interpretation of theme_xxx=default.
  • The lesson I see is: the theme is a big deal. Changing theme_xxx is a much more visible/complicated/subjective affair than changing (say) max_attachments. If we exercise the prerogative to change default, then the blast-radius will be too big.
• That logic could be in the installer / upgrader / status-checks. (These tools manage an explicit value -- which we can compute/override/preserve in various ways.)
  • This model is more work (for us) than a declarative default (like Civi\Core\Themes::DEFAULT_THEME = greenwich or like Core.setting.php with default=>minetta in Riverlea rollout - set Minetta as default, freeze previous default of Greenwich, sidestep DEFAULT_THEME #31986).
  • It's also more work (for us) than runtime-computation (like theme_xxx=default).
  • But it is nevertheless a predictable/familiar game.
  • This model gives more precise control over the blast-radius. Transitions can be staged.
  • It's more proportionate to the expectations/requirements for themes.

(^^ Edited a little for clarity.)

I can see the expediency of this... But... force everyone to an explicit setting

• Yeah, it is expedient.
• It's also future-aligned. The value should be explicit (augmented by installer/upgrader/status-checks) -- because the theme-setting is a big deal, and we should be able to control the blast-radius anytime we revise it.
• I suspect you feel a bit underwhelmed looking at this patch -- because it's not comprehensive.
  • This doesn't clear-out the tight coupling to Greenwich.
  • I completely agree with that goal.
  • We should do that.
  • It doesn't need to be at the time of 6.0 freeze. It's more complicated. (I'd rather push that to 6.1 or 6.2 than ship a rushed/partial/buggy variant in 6.0.)

The value should be explicit (augmented by installer/upgrader/status-checks)

Interesting. This is the crux for me.

I am not underwhelmed by this patch, I'm worried it overreaches... the "making minetta the explicit setting" is a one-line patch, but is something we cannot step back from.

I'm fairly convinced by what you've said above...

we should be able to control the blast-radius anytime we revise it

So was thinking about this some more. I think making it explicit is in practice always going to restrict the blast radius of future changes. That may be appropriate - but it's not "this change allows us to choose whatever blast radius we want going forward".

One group we are foregoing the ability to blast is "people who only have Minetta because the 6.0 upgrader gave it to them".

Ok, I'm a still a little nervous, but (as Mike Skinner once said) let's push things forward d