VersionProvider caching is broken

[emteknetnz]

Discovered during #10478

The tests in CMS4 VersionedProviderTest currently pass when they kind of should not

The following $key assignments in VersionProvider generate keys with invalid characters

Where $key is a filesystem path

$key = sprintf('%s-%s', $this->getComposerLockPath(), 'all');
$key = sprintf('%s-%s', $this->getComposerLockPath(), $module);

The contains the / character, which is invalid - https://github.com/symfony/cache-contracts/blob/main/ItemInterface.php#L43
Called via:
https://github.com/symfony/cache/blob/4.4/CacheItem.php#L170
https://github.com/symfony/cache/blob/4.4/Simple/AbstractCache.php#L77

Marked as low priority because while the caching is broken, things still work perfectly fine on the front-end. So fixing this would only net a tiny performance benefit

Non issue in CMS 5 because the cache key validation logic isn't called

PR

• VersionProvider always write to cache #10889 (CMS 5 only)

[lekoala]

Still an issue in SS5
#10889

[GuySartorelli]

#10889 resolved this for CMS 5. Still an issue for CMS 4.

[lekoala]

it's probably possible to apply the same fix to ss4 if needed