Missing class from precompiled output after building with Docker

[omegahm]

I have a brand new Rails (8.0.2) project with Ruby 3.4.2:

$ rails new ThisAndThat --css tailwind --js importmap --database sqlite3

I add a div with a class of max-h-8 to the layout/application.html.erb file.
If I now run tailwindcss binary, I get:

$ bundle exec tailwindcss --input app/assets/tailwind/application.css -o - | grep "max-h-8"
≈ tailwindcss v4.1.5
  .max-h-8 {
Done in 39ms

This works. So it shows in my local development just fine.

I now want to deploy my project with a Docker image. I run:

$ docker buildx build --progress plain --platform linux/amd64/v2 --tag thisandthat --load .

which builds me a Docker image. I build with that platform argument, because I am on an M2 MacBook and want to run the Docker image on a Ubuntu server.

I launch an interactive shell with:

$ docker run -it --rm thisandthat bash

and look at the compiled Tailwind CSS for the class max-h-8:

$ cat public/assets/tailwind-* | grep "max-h-8"

This comes up empty! 🚫

If I do the same with another class, say z-auto, or even max-h-[8px] it works flawlessly.

What am I missing?

[omegahm]

Installing Node and npm in the same Docker image and trying compiling the CSS yields the correct results.

I've installed Node and npm by adding the following after the assets:precompile step in Dockerfile.

RUN curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.3/install.sh | bash
ENV NVM_DIR=/root/.nvm
RUN bash -c "source $NVM_DIR/nvm.sh && nvm install 23"
RUN bash -c "source $NVM_DIR/nvm.sh && npm install tailwindcss @tailwindcss/cli"
RUN bash -c "source $NVM_DIR/nvm.sh && npx @tailwindcss/cli -i app/assets/tailwind/application.css -o - | grep \"max-h-8\""

[omegahm]

I see this is a duplicate of tailwindlabs/tailwindcss#17728 and #534. I'll follow along there instead and close this issue.

[flavorjones]

Just a note that the underlying cause seems to have been discovered, and there are some workarounds you can try.

• underlying cause: Floating point values are truncated when run on M1 with x86_64 emulation (via Docker) oven-sh/bun#19677
• explanation and workarounds: Styles aren't generated when building a Docker image for ARM64 on a 2019 Intel MacBook Pro tailwindlabs/tailwindcss#17728 (comment)