This PR fixes an issue where an `@source` pointing to a file in a nested
folder was not scanned when a later `@source` pointed to a file in a
parent folder.
E.g.:
```css
@source "./nested/index.html";
@source "./index.html";
```
When using `@source` pointing to a specific file, then we want to make
sure that we ignore _other_ files since they are not listed explicitly.
To ensure that these patterns don't read other files, we inject a `*`
ignore pattern before it. You can think of the above being expanded to:
```rs
Ignored { base: "/project/src/nested", pattern: "*" }
Pattern { base: "/project/src/nested", pattern: "/index.html" }
Ignored { base: "/project/src", pattern: "*" }
Pattern { base: "/project/src", pattern: "/index.html" }
```
The problem with this is that the `Ignored { base: "/project/src",
pattern: "*" }` pattern results in ignoring the `nested` folder as well.
This means that we never even walk into the `nested` folder, so the
earlier `@source "./nested/index.html"` never matches anything.
We could switch the order in user land, but that's going to be hard to
maintain (and order matters for undoing/redoing earlier rules, so we
can't re-order internally either). Instead, we can scope the ignore
pattern to the _current_ path only, and not deeply nested. In other
words, the pattern should become:
```diff
- *
+ /*
```
It's a very subtle difference, but the pattern from above will now
become:
```diff
Ignored { base: "/project/src/nested", pattern: "*" }
Pattern { base: "/project/src/nested", pattern: "/index.html" }
- Ignored { base: "/project/src", pattern: "*" }
+ Ignored { base: "/project/src", pattern: "/*" }
Pattern { base: "/project/src", pattern: "/index.html" }
```
We already do this when an unrestricted root (e.g. `@source "./nested"`)
lives inside the base of a restricted pattern. This works because every
source base is also its own walk root, and a `/*` pattern only matches
direct children so it can't ignore anything when walking from the nested
root itself.
This PR extends that same check to restricted pattern bases: if another
`@source` pattern has its base nested inside the current base, we emit
`/*` instead of `*`.
Note that we only relax the pattern to `/*` when such a nested root
actually exists. Sibling folders that no `@source` points into (e.g. an
`ignore-me` folder next to `nested`) are still direct children, so they
still match `/*` and are never walked.
Fixes: #20333
## Test plan
1. Added a regression test with the reproduction setup
2. Added a similar test with another sibling folder that should still be
ignored
3. Tested it against the actual reproduction:
Before:
<img width="797" height="463" alt="image"
src="https://github.com/user-attachments/assets/893bb872-f5cf-4c5a-bfb5-2dc1043b5a39"
/>
After:
<img width="794" height="460" alt="image"
src="https://github.com/user-attachments/assets/a59aae45-68ad-4fe3-b21f-b568f535d24f"
/>
Notice that the `text-green-500` now appears as expected.
7811d74f37