fix: Correctly process urls when they are rewritten to contain space

[Artur-]

Description

If a CSS file contains

background: url(folder/foo.png)

and the processing of the URL causes "folder" to be rewritten to e.g. "other folder", then the end result cannot be

background: url(other folder/foo.png)

because using space without wrapping the url with ' or " is not allowed.

This rewrites the url in this case to

background: url('other folder/foo.png')

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the Commit Convention.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

[Artur-]

I wonder if this could break if used inside JS, inside a string using '.... The other approach would be to not wrap but instead encode the url, this would not break because of the wrapping but could it accidentally double encode in some cases?

[patak-dev]

I wonder if this could break if used inside JS, inside a string using '.... The other approach would be to not wrap but instead encode the url, this would not break because of the wrapping but could it accidentally double encode in some cases?

I thought the same when reviewing the PR, it would require checking where this needs to be decoded afterward. I think we could merge this as a first step, and it would be interesting if you could generate a failing test to justify going further and encode/decode

[bluwy]

LGTM. Re space encoding, perhaps it's related to #7305, but I haven't fully understand if that PR is safe yet.

[Artur-]

It would be interesting if you could generate a failing test to justify going further and encode/decode

I tried to do this but either everything is ok or I did not manage to find the failing combination. Maybe it will show up later...
Instead I hit #7510