Enable CSS and JavaScript aggregation by default in the standard profile

This patch changes the default performance settings in standard.install.

Big +1 obviously.

Patch enable internal caching and set max-age to 1 day.

It works. Is there anything else needed for RTBC?

Big +1 to CSS/JS aggregation. Zero problems there.

Not sure about page cache's expiration being set to 1 day. What about sites with fast-changing content?

@Wim Leers Any preference on cache expiration time? At a guess, I would say that the common case usage isn't fast-changing content.

I'll work on fixing the tests to allow for this patch. Not too sure how to check for the help module CSS file being present though...

@catch For now I've removed the max-age setting, as it also broke the search tests.

We can always look at changing it once #1605290: Enable entity render caching with cache tag support is solved.

#7: But the max_age setting is not for internal use only. It propagates into the Cache-Control header that is sent to browsers. So partial render cache clears would not propagate to end users, which is my concern. At least, that's what the UI text says:

The maximum time a page can be cached. This is used as the value for max-age in Cache-Control headers.

If this applied not to caching headers sent to visitors, but only to internal caches, then anything goes. I'd be fine with much higher values than "one day" even (though then cache size of course becomes a concern, assuming it is not bounded nor capped in LRU manner).

Minor comment change to patch in #8.

#10: drupal-standard-profile-performance-defaults-1985084-10.patch queued for re-testing.

This seems like the kind of issue that's going to be debated for a while longer, but for what it's worth #10 does turn on all performance optimizations on install. So I'll go ahead and mark it as RTBC.

Before (un-patched installation of D8 standard profile):

After (patched installation of D8 standard profile):

This one has catch written alllll over it. :)

I'd hate to block something but I have a general uneasy feeling about this going in before the rebuild script in #1872522: Compiled data in PHP storage is cleared too late in drupal_flush_all_caches()

@catch Alsomsee my comment at #9.

This patch provides a config file instead, but depends on the fix for #1986090: Profile config does not overwrite module default config on install (system.cron.yml).

Also what happens if you have internal page caching enabled but maximum age set to 0?

After reading the code, it seems that the internal page cache is set only if max age > 0. So you must have both (use_internal checked and max_age > 0) to enable internal page caching. That's what we have in tests too.

#19: drupal-standard-profile-performance-defaults-1985084-19.patch queued for re-testing.

This would make me happy

23: drupal-standard-profile-performance-defaults-1985084-23.patch queued for re-testing.

#1986090: Profile config does not overwrite module default config on install (system.cron.yml) would make this much simpler.

This patch only covers the CSS + JS aggregation. Page caching is covered in #606840: Enable internal page cache by default

Corrected YAML format.

Added missing \Drupal:: reference.

33: drupal-standard-profile-performance-defaults-1985084-33.patch queued for re-testing.

+++ b/core/modules/help/lib/Drupal/help/Tests/HelpTest.php
@@ -64,11 +64,19 @@ public function testHelp() {
+    // Disable css aggregation so we can check if help.css exists.

+++ b/core/modules/system/lib/Drupal/system/Tests/Common/NoJavaScriptAnonymousTest.php
@@ -35,6 +35,11 @@ protected function setUp() {
+    // Disable JS aggregation so we can check for HTML5 shiv.

You can check for the presence of the HTML5 shiv by looking at drupalSettings.ajaxPageState. There are other tests that use this that you can use as an example.

I'm not sure which issue but this is now fixed.