PostCSS/Tailwind JIT not recompiling correctly in watch mode

Describe the bug

We use tailwindcss/postcss as part of our svelte-preprocess config (sveltePreprocess({ postcss: true })), and with esbuild-svelte, if we add new tailwind classes (ie. not appearing in our existing code), watch triggers an incremental build but tailwindcss doesn’t seem to be re-running…or if it is, it’s not noticing the new classes.

The issue is fixed by restarting the esbuild-svelte process (the first build always runs tailwind correctly), so it’s not very severe as there is an easy workaround.

To Reproduce Steps to reproduce the behavior:

1. Start using a new tailwindcss class in a .svelte file (eg. invisible)
2. Hit save
3. Wait for incremental build to finish and refresh the browser

Expected behavior New tailwind class works (eg. the element disappears due to the invisible class)

Environment (please complete the following information):

• esbuild-svelte version: esbuild-svelte@0.6.0
• esbuild version: esbuild@0.13.13
• Svelte preprocessors used (if any): svelte-preprocess@4.9.8, with postcss: true

Additional context

Maybe there’s something simple I’m missing? I know this might not be an esbuild-svelte issue, but I’m sure others will eventually run into the same problem. I’m happy to post more of the config if that’ll help, or even a small repro. I just wanted to hear your thoughts first before spending time on that (in case there’s something obvious).

Thanks again for your work on this project!

[EMH333]

Ah that’s an interesting metric! I’ll look at adding a filter to the caching logic (for both true and "overzealous", though one will block and the other will allow caching… that’ll be fun) at some point in the future, but leave it at this for now

[tyler-boyd]

Thanks, it works! Definitely wise to keep it behind an option, as running tailwind is fairly expensive (the build time with cache: "overzealous" is about halfway between true and false)