"watch" command does not support nested bundles (anymore) about webassets

[ryansully]

I first noticed this issue when applying debug=False to a compiled CSS bundle, applying compression and data URI filters intended for production further up while registering the bundle, and noticing that all filters were being applied in debug mode instead of just the compiled CSS filter.

I came up with a nasty workaround in the meantime: include an empty CSS file at a bundle level just above the compiled CSS bundle, at the same level as or before applying other filters. Somehow this causes only the compiled CSS bundle to be filtered/compiled, while not applying other filters.

Of course this isn't optimal, requiring an empty/dummy CSS file to be created and referenced everywhere you want to isolate the compiled CSS filter from other CSS filters, as well as adding extra unnecessary overhead during an assets build. Hopefully this provides an idea or motivation for a more permanent solution.

[miracle2k]

Interesting. That's actually a separate problem, but I see what it is. These outer bundles which only define filters but no content or output are not "built" directly, but only push their filters down to the nested ones (I call them container bundles).

Still, I would love to see an code snippet as an example of your configuration, to ensure I'm understanding correctly.

[ryansully]

scss_bundle = Bundle('scss/styles1.scss',
    'scss/styles2.scss',
    filters='pyscss', debug=False,
    output='gen/scss/styles.css')

This will compile with compression and data URIs:

css_compressed_bundle = Bundle(scss_bundle,
    filters='yui_css,datauri',
    output='gen/css/compressed_bundle.css')

This will only compile SCSS, without compression and data URIs:

css_compiled_only_bundle = Bundle(scss_bundle,
    'css/empty.css',  # empty css file
    filters='yui_css,datauri',
    output='gen/css/compiled_only_bundle.css')

Note that everything works as intended when environment.debug == False, this issue only occurs when debug == True.

[miracle2k]

Ryan, I can't reproduce this now (https://gist.github.com/2835601 works for me), but the build code did receive some modifications recently, so maybe this was fixed by accident. Still, allow me to add two notes:

• You cannot test such a thing by calling bundle.build() while environment.debug=True; it would just pretend that debug=False, because build() with debug=True makes no sense. Instead, bundle.urls() needs to be used for testing.

• Using recent master, you can do

  scss_bundle = Bundle('scss/*.scss',
  filters='pyscss,yui_css,datauri', output='gen/css/compiled.css')

  without needing a nested bundle at all, so this should also obsolete the empty.css workaround.