FIX Class manifest is not caching enums

[lekoala]

Description

Fix #11531

Enums were not being added to cache, but validated and required

Manual testing steps

See related issue

Basically, this will ensure that validateItemCache will actually return true
Currently it will always return false unless i've missed something somewhere...

Issues

Fixes #11531

Pull request checklist

• The target branch is correct
  • See picking the right version
• All commits are relevant to the purpose of the PR (e.g. no debug statements, unrelated refactoring, or arbitrary linting)
  • Small amounts of additional linting are usually okay, but if it makes it hard to concentrate on the relevant changes, ask for the unrelated changes to be reverted, and submitted as a separate PR.
• The commit messages follow our commit message guidelines
• The PR follows our contribution guidelines
• Code changes follow our coding conventions
• This change is covered with tests (or tests aren't necessary for this change)
• Any relevant User Help/Developer documentation is updated; for impactful changes, information is added to the changelog for the intended release
• CI is green

[lekoala]

Actually now i see why enums are not there

silverstripe-framework/src/Core/Manifest/ClassManifest.php

Lines 694 to 701 in f40b1a4

	if ($changed && $this->cache) {
	$cache = [
	'classes' => $classes,
	'interfaces' => $interfaces,
	'traits' => $traits,
	];
	$this->cache->set($key, $cache);
	}

[lekoala]

For reference, it's due to this PR
d3f1043

which seems to have forgotten to store the enums in the cache

@kinglozzer did I miss something here?

[kinglozzer]

I can’t remember (or think of) any reason why they shouldn’t be included in the cache, so it’s probably just an oversight in the original PR

[lekoala]

an additionnal improvement would be to not store empty arrays and simply consider missing keys as empty arrays.
this should reduce the cache size by a large margin, because it's currently storing a lot of empty traits => [] and enums => []

[lekoala]

since i made benchmarks for my other PR, i took the opportunity to benchmark this as well

without the fix

manifest (no cache folder)
Time: 8s
Peak memory: 16.000Mb
Memory: 16.00Mb

manifest (regenerate cache)
Time: 7s
Peak memory: 16.000Mb
Memory: 16.00Mb

with the fix

manifest (no cache folder)
Time: 9s
Peak memory: 16.000Mb
Memory: 16.00Mb

manifest (regenerate cache)
Time: 640ms
Peak memory: 14.000Mb
Memory: 14.00Mb

The missing cache key makes the cache regeneration take 7s instead of 640ms... (with a regular hard drive (no ssd) and a file based cache... this could be less worse on a better hard drive)