Since we (optionally) support source maps now it's possible that a later
PostCSS plugin that *still* does url rewriting might fail to do so
correctly because nodes will have preserved source locations in dev
builds where before we "pretended" that everything came from the
original file.
But, because we can't know if such a plugin is present, disabling this
behavior when source maps are enabled could cause issues *and* would be
a breaking change.
I wish everything *could just work* here but realistically we can't know
what plugins have run before our PostCSS plugin or what plugins will run
after so the best option (I think) we can offer here is to allow users
to disable url rewriting at the plugin level.
Fixes#16700
Fixes#16636
This PR enables URL rebasing for PostCSS. Furthermore it fixes an issue
where transitive imports rebased against the importer CSS file instead
of the input CSS file. While fixing this we noticed that this is also
broken in Vite right now and that our integration test swallowed that
when testing because it did not import any Tailwind CSS code and thus
was not considered a Tailwind file.
## Test plan
- Added regression integration tests
- Also validated it against the repro of
https://github.com/tailwindlabs/tailwindcss/issues/16962:
<img width="1149" alt="Screenshot 2025-03-05 at 16 41 01"
src="https://github.com/user-attachments/assets/85396659-d3d0-48c0-b1c7-6125ff8e73ac"
/>
---------
Co-authored-by: Robin Malfait <malfait.robin@gmail.com>
Co-authored-by: Jordan Pittman <jordan@cryptica.me>
