To support this, we now run Node-Sass-style relative loads outside of
the Node importer. This allows the evaluator to check whether a
relative load succeeded and use that to determine whether the
stylesheet counts as a dependency.
See sass/sass#3065
Prior to this, the watcher handled all the logic around recompiling
stylesheets if an upstream file was deleted or added in a way that
could affect their import resolution. This left a gap where the
stylesheet graph wouldn't be aware that a newly-added file had become
upstream dependency of an existing downstream file, leading to
recompilation failures.
This commit fixes that by moving all that logic into the stylesheet
graph. The graph now has full and sole responsibility for providing a
consistent view of which stylesheets depend on one another even as the
shape of the graph changes, and the watcher is just a client of that
logic.
Closes#550
These can be passed as an ImportCache now, so they make the API more
confusing for relatively little benefit.
This also changes the const AsyncImportCache.none field to a non-const
AsyncImportCache.none() constructor. The const field didn't make sense
for a couple reasons: first, it wouldn't use a user's custom logger;
and second, it couldn't cache any relative imports, which were still
possible when the initial file was loaded from disk.
When a stylesheet is imported, the parsed stylesheet object is cached
based on its canonical URL. However, the stylesheet.span.sourceUrl was
based on the text of the import that was used to load that stylesheet.
The idea was to make the source URL in stack traces look nicer, but it
meant that relative URLs could be resolved based on the old importer's
URL before being sent to the new importer, which caused bugs.
Now stylesheet.span.sourceUrl is always the canonical URL of the
stylesheet, and thus safe to cache. We then use the import cache to
convert the canonical URL to a human-friendly URL at the point at
which we generate stack traces.
This also deprecates support for relative canonical URLs. The
semantics of these URLs were always unclear, and with the new change
in import internals the old behavior doesn't make much sense. It's
preserved for backwards-compatibility, but deprecated.
We were resolving URLs relative to the canonical URL rather than the
original URL, which broke importers for which those were different,
like the package importer.
Closes#334
