Fixes three NameErrors which were introduced by the previous commit,
leading to it being reverted.
These NameErrors slipped through because the script was not tested on
any themes that had zero SCSS overrides.
Instead of using libsass-python's `sass` module, which is incompatible
with Python 3.11, we now directly use libsass-python's `_sass` module,
which directly binds to the underlying C++ libsass library.
This ensures that the Sass build will not a blocker for the edx-platform
Python 3.11 upgrade, which needs to land in Redwood.
For more details, see the docstring at scripts/compile_sass.py#L167
This PR implements much of the static assets rework ADR [1], including:
* `npm run build[-dev]`, and its subcommands,
* `npm run webpack[-dev]` and
* `npm run compile-sass[-dev]`.
This is backwards-compatible. `paver update_assets` should not be affected.
The new command warns that it is "experimental" for a few reasons:
* `npm run build` will fail in the webpack phase unless you first
run `xmodule_assets`. This will be changed soon [2].
* We have tested the new build, but not quite so thoroughly that we'd
recommend it as the production default yet. Once the xmodule_assets
work lands, we'll share this on the forums so early adopters can try it
out.
* The commands lack some top-level documentation. Once they stabilize more,
we'll add a section to the README that explains how and when to use `npm run
build` and its subcommands and its env vars.
* `npm run watch` is not yet implemented.
References:
1. https://github.com/openedx/edx-platform/blob/master/docs/decisions/0017-reimplement-asset-processing.rst
2. https://github.com/openedx/edx-platform/pull/32685
Part of: https://github.com/openedx/edx-platform/issues/31604
