Rails 3.1 asset pipeline doesn't pick up changes to @import'd sheets

I use @import'd partial sheets to organize my css/sass:

/app
  /assets
    /stylesheets
      _constants.sass
      _layout.sass
      ...
      app.css.sass

app.css.sass:
  @import _constants.sass
  // basic styles
  @import _layout.sass
  @import ...

app.css.sass has an @import rule for _layout.sass, which allows me to share mixins and variables amongst the raw sass files before they're complied down into app.css

The problem is that Rails doesn't recognize changes to the @import'd partials (_layout.sass) and won't regenerate app.css until I make a change to the actual app.css.sass file itself. This dramatically s开发者_StackOverflow社区lows down my workflow and means I have to add/remove blank lines from app.css.sass to see changes. Never had this problem in 3.0.

Is there a way of forcing sass assets to regenerate on every server request in development?

Using a depend_on directive may do what you require. This makes the given file a dependency of the base file (so the base file is regenerated when the dependency changes), but doesn't include it in the bundle.

For example:

/*
*= depend_on _layout.sass
*= depend_on _constants.sass
*/
@import _layout.sass
@import _constants.sass

See this sass and sprockets blog post as well as the sprockets documentation (especially the directives section).

The answer from nanothief led me to the solution (thank you!) but in an indirect way. Once I finally found the time to get back on here and look up the referenced post, it had been updated to say that the fix was no longer needed.

Sure enough, it appears that this bug has been fixed in Rails 3.1.0 stable with sass-rails for 3.1.0. So good! I've confirmed that updating the gems does get everything back to working correctly, tested in a couple of apps.