Include .scss and .sass in stats.json hashes

[oliveryasuna]

Describe your motivation

We use SASS (.scss) stylesheets under /frontend/styles. These are imported and fully supported by Vite. It seems that the vaadin:stats Vite plugin does not generate hashes for them and store in stats.json#frontendHashes. Because of this, even with prod.bundle, the Vaadin Maven/Gradle plugins think there are new files, and thus, do not use the existing bundle.

Describe the solution you'd like

const projectFileExtensions = ['.js', '.js.map', '.ts', '.ts.map', '.tsx', '.tsx.map', '.css', '.css.map']; needs to also support .scss and .sass.

Is there a reason those file extensions are not already included? If not, happy to contribute this simple PR.

Describe alternatives you've considered

I could write a Vite plugin that computes and adds the hashes.

I could create a Gradle task that compiles the SASS files and outputs them to /frontend/styles.

Both options seem messy.

Additional context

I discovered this while investigating ways to speed up our builds, in lieu of Vaadin's proper Gradle caching support. #17941

This idea came from our recent endeavour to speed up builds. Relevant issues:

• The vaadinPrepareFrontendTask gradle task is not cached #17941
• Add support for build caching of in-place processed files gradle/gradle#27696
• Include .scss and .sass in stats.json hashes #19527
• Filter classpath scanning for FrontendDependencies #19528
• Document the Gradle plugin's filterClasspath property/closure docs#3477
• Consider switching from Reflections to a maintained library #19543

[steve-todorov]

In addition to scss and sass extensions, people might also use less so might be beneficial to add it to the extension list as well.

[oliveryasuna]

Maybe extensions should be customizable with an include/exclude pattern.

[oliveryasuna]

I opened a draft PR to demonstrate my proposal: #19550