URLManifestItem.url shouldn't contain non-URL-unit characters

[gsnedders]

Rendered

[gsnedders]

(There's also the variant of this RFC where all we do is url.replace(" ", "%20") which avoids the "space separated URLs" problem. But it still carries the same risks.)

[foolip]

One question here is whether we should disallow test file paths that contain spaces, or whether we should just escape these in the URL.

Given how few such files there are, let's just disallow them.

[foolip]

I don't think banning spaces in test names is worthwhile.

I just searched for spaces in filenames and found two cases that don't seem intentional:

https://github.com/web-platform-tests/wpt/pull/46253 https://github.com/web-platform-tests/wpt/pull/46254

Is there much of a downside to banning spaces?