Ben Lindsay
Ben Lindsay

Reputation: 1796

How can I compile Bootstrap 4 scss with python webassets?

I'm trying to simply compile Bootstrap 4 with python webassets and having zero success. For now I'm just trying to do this within the bootstrap/scss directory so path issues are less of a big deal. Within this directory I have added a main.scss file with one line:

@import "bootstrap.scss";

I have a script called test_scss.py that looks like this:

from webassets import Bundle, Environment
my_env = Environment(directory='.', url='/')
css = Bundle('main.scss', filters='scss', output='all.css')
my_env.register('css_all', css)
print(my_env['css_all'].urls())

When I run this command, I get an error trace like this:

Traceback (most recent call last):
  File "./test_scss.py", line 11, in <module>
    print(my_env['css_all'].urls())
  File "/Users/benlindsay/miniconda/lib/python3.6/site-packages/webassets/bundle.py", line 806, in urls
    urls.extend(bundle._urls(new_ctx, extra_filters, *args, **kwargs))
  File "/Users/benlindsay/miniconda/lib/python3.6/site-packages/webassets/bundle.py", line 765, in _urls
    *args, **kwargs)
  File "/Users/benlindsay/miniconda/lib/python3.6/site-packages/webassets/bundle.py", line 619, in _build
    force, disable_cache=disable_cache, extra_filters=extra_filters)
  File "/Users/benlindsay/miniconda/lib/python3.6/site-packages/webassets/bundle.py", line 543, in _merge_and_apply
    kwargs=item_data)
  File "/Users/benlindsay/miniconda/lib/python3.6/site-packages/webassets/merge.py", line 276, in apply
    return self._wrap_cache(key, func)
  File "/Users/benlindsay/miniconda/lib/python3.6/site-packages/webassets/merge.py", line 218, in _wrap_cache
    content = func().getvalue()
  File "/Users/benlindsay/miniconda/lib/python3.6/site-packages/webassets/merge.py", line 251, in func
    getattr(filter, type)(data, out, **kwargs_final)
  File "/Users/benlindsay/miniconda/lib/python3.6/site-packages/webassets/filter/sass.py", line 196, in input
    self._apply_sass(_in, out, os.path.dirname(source_path))
  File "/Users/benlindsay/miniconda/lib/python3.6/site-packages/webassets/filter/sass.py", line 190, in _apply_sass
    return self.subprocess(args, out, _in, cwd=child_cwd)
  File "/Users/benlindsay/miniconda/lib/python3.6/site-packages/webassets/filter/__init__.py", line 527, in subprocess
    proc.returncode, stdout, stderr))
webassets.exceptions.FilterError: scss: subprocess returned a non-success result code: 65, stdout=b'',
stderr=b'DEPRECATION WARNING: Importing from the current working directory will
not be automatic in future versions of Sass.  To avoid future errors, you can add it
to your environment explicitly by setting `SASS_PATH=.`, by using the -I command
line option, or by changing your Sass configuration options.

Error: Invalid CSS after "...lor}: #{$value}": expected "{", was ";"
        on line 4 of /Users/benlindsay/scratch/python/webassets/test-2/bootstrap/scss/_root.scss
        from line 11 of /Users/benlindsay/scratch/python/webassets/test-2/bootstrap/scss/bootstrap.scss
        from line 1 of standard input
  Use --trace for backtrace.

If I follow the instructions and set environment variable SASS_PATH=., that gets rid of that part of the error message, but I still get the error

Error: Invalid CSS after "...lor}: #{$value}": expected "{", was ";"
        on line 4 of /Users/benlindsay/scratch/python/webassets/test-2/bootstrap/scss/_root.scss
        from line 11 of /Users/benlindsay/scratch/python/webassets/test-2/bootstrap/scss/bootstrap.scss
        from line 1 of standard input
  Use --trace for backtrace.

I don't know SCSS syntax well yet, but I'd bet a lot of money this is me doing something wrong and not an error in the Bootstrap SCSS. Any thoughts of what I'm doing wrong would be greatly appreciated.

Upvotes: 1

Views: 478

Answers (1)

Ben Lindsay
Ben Lindsay

Reputation: 1796

Turns out it actually kind of was a problem on Bootstrap's end. See https://github.com/sass/sass/issues/2383, specifically the quote:

This is a bug in our implementation—the parser shouldn't crash—but those Bootstrap styles aren't valid for Sass 3.5 as written.

Anyway, I just needed to update to the latest version of Ruby Sass (which apparently the webassets module depends on) and that fixed it.

Upvotes: 1

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