[Question] Is there a way to force SASS compilation on every build?

[yso8]

Hi,

I am using this package in a Blazor WASM project. I am running into a situation where my generated site.css exists but contains incorrect/stale styles (eg. after switching git branches).

The Problem: It seems the compiler skips the task because it detects no changes in the source files, but I need to force a regeneration to ensure the CSS is correct. I tried adding a task in my .csproj (Target BeforeBuild/Before Sass Compiler) to remove the .css file, but it doesn't seem to trigger the SASS compiler to run again.

The Question: Is there an existing property or configuration (like true) to force the SASS compilation on every build, regardless of the file state?

I might have missed an existing option in the documentation.

Thanks

[adiessl]

Dart Sass will compile everything on every invocation by default.

This library, however, explicitly appends the --update flag before invoking the compilation:

AspNetCore.SassCompiler/AspNetCore.SassCompiler.Tasks/CompileSass.cs

Line 251 in 9748f74

processArguments.Append(" --update");

From the Dart Sass documentation:

If the --update flag is passed, Sass will only compile stylesheets whose dependencies have been modified more recently than the corresponding CSS file was generated.

---

Does manually removing the .css before triggering the build work for you? If yes, your custom task might not be triggered early enough.

Another approach you could try would be to touch the .scss file in your task to make sure the compiler thinks it has changed.

[yso8]

Sorry, I'm not very comfortable with the Dart tooling, thanks for pointing me to the code and the documentation that explain this behavior.

About your questions:

Deleting the generated file:
Manually removing the .css does work. I attempted to handle this through a task in the .csproj, but I wasn’t able to make it run early enough to bypass the compiler’s internal check.

Updating the timestamp:
As you suggested, this works perfectly.
I implemented your idea using a simple task to refresh the source file timestamp :

<Target Name="ForceCleanSass" BeforeTargets="Compile Sass">
   <Touch Files="$(ProjectDir)wwwroot\scss\site.scss" />
</Target>

That solves the immediate problem, although touching source files during build clearly feels more like a pragmatic workaround than a clean solution.

In the long term, could it be worth making the --update argument optional, perhaps via a dedicated property or do you think there would be little demand for a way to force Sass compilation without altering project files?

Thanks again for the help!

[adiessl]

In the long term, could it be worth making the --update argument optional, perhaps via a dedicated property or do you think there would be little demand for a way to force Sass compilation without altering project files?

To me, giving the user options and not forcing a default is never a bad thing. What are your thoughts, @koenvzeijl and @sleeuwen?