Do some
background-image: url(whatever.svg);
in your css module and it comes out like
background-image: url(https:/w/extensions/whatever/whatever.svg);
Only it seems to do this regardless of what protocol the rest of the site is/supports and results in no image on sites lacking ssl?
@ashley did some digging and found cd54c03e86e6a2a0caa6c6943b22dfa052e874bd, which appears to be responsible.
In "general" local file paths in CSS do not come out that way. I'll need a bit more information about your config and the module in question to narrow this down.
Does the site in question generally still work? E.g. the various uses of relative/local file paths in core extensions that reference a PNG or SVG file, are those also broken?
What do these look like? $wgServer, $wgScriptPath, $wgResourceBasePath, $wgExtensionAssetsPath, $wgStylePath.
What class of module is used here, a plain ResourceLoaderFileModule defined in extension.json, or something else?
Okay, I spoke too soon. I can now reproduce this consistenty on my localhost and also on Beta Cluster. On the latter, the icons seem to work due to an unintentional feature where by a domain-less URL with a scheme in front is interpreted as path URL, which is definitely not intentional.
The main issue is that the domain is missing. The protocol just comes along for the ride for internal relative protocol URL expansion, which will be stripped again once the domain is inserted correctly.
Change 643383 had a related patch set uploaded (by Krinkle; owner: Krinkle):
[mediawiki/core@master] resourceloader: Fix malformed "https:/w/resources" mapping in CSSMin
Change 643383 merged by jenkins-bot:
[mediawiki/core@master] resourceloader: Fix malformed "https:/w/resources" mapping in CSSMin
Change 643160 had a related patch set uploaded (by Krinkle; owner: Krinkle):
[mediawiki/core@wmf/1.36.0-wmf.19] resourceloader: Fix malformed "https:/w/resources" mapping in CSSMin
Change 643161 had a related patch set uploaded (by Krinkle; owner: Krinkle):
[mediawiki/core@wmf/1.36.0-wmf.18] resourceloader: Fix malformed "https:/w/resources" mapping in CSSMin
Change 643161 merged by jenkins-bot:
[mediawiki/core@wmf/1.36.0-wmf.18] resourceloader: Fix malformed "https:/w/resources" mapping in CSSMin
Mentioned in SAL (#wikimedia-operations) [2020-11-25T20:49:24Z] <krinkle@deploy1001> Synchronized php-1.36.0-wmf.18/includes/libs/CSSMin.php: I26ed3e5e9a - fix T268308 (duration: 00m 59s)