Tailwind v4 @source directive ignores subdirectories with .gitignore

[jhh]

What version of Tailwind CSS are you using?

v4.0.0-beta.8

What build tool (or framework if it abstracts the build tool) are you using?

None, using CLI

What version of Node.js are you using?

v20.18.1

What browser are you using?

N/A

What operating system are you using?

tested on macOS and Linux

Reproduction URL

https://github.com/jhh/tailwind-gitignore

Describe your issue

Adding a .gitignore file to a directory referenced by a @source directive in a Tailwind CSS source file causes the referenced directory to be ignored.

I discovered this because the uv Python packaging tool creates a .gitignore in the .venv directory it uses and I couldn't @source a template directory within it. Manually deleting .venv/.gitigore fixes the issue.

[e-krebs]

this is a documented behavior: https://tailwindcss.com/docs/v4-beta#automatic-source-detection

[jhh]

I went over that documentation pretty carefully while I was trying to figure out why I wasn't picking up template sources. I think this is still a bug. The docs state that "And if you ever need to explicitly add a source that’s excluded by default, you can always add it with the @source directive...", reinforced by an example @source directive pointing to a directory within node_modules (nearly always .gitignored).

Taken from the repro above, works with one .gitignore:

.
├── .gitignore # ignores ignored/ dir
├── base.css
├── ignored
│   └── template.html # works as documented, @source will pick up classes
├── package-lock.json
├── package.json
├── README.md
└── test.html

Does not work when second gitignore is present in ignored directory:

.
├── .gitignore  # ignores ignored/ dir
├── base.css
├── ignored
│   ├── .gitignore # adding this, ignores *
│   └── template.html # this will not be seen by @source
├── package-lock.json
├── package.json
├── README.md
└── test.html

[e-krebs]

according to the (limited) doc, in neither of those two cases should the template file classesnbe picked up, so that's probably where the bug is.