- this fixes a bug where if we save a concretized sug-DAG where a package
had been patched by a dependent, and the dependent was not in the DAG,
we would not read in all patches correctly.
- Rather than looking up patches in the DAG, we look them up globally
from an index created from the entire repository.
- The patch cache is a bit tricky for several reasons:
- we have to cache information from packages, specifically, the patch
level and working directory.
- FilePatches need to know which package owns them, so that they can
figure out where the patch lives. The repo can change locations from
run to run, so we have to store relative paths and restore them when
the cache is reloaded.
- Patch files can change underneath the cache, because repo indexes
only update on package changes. We currently punt on this -- there
are stub methods for needs_update() that will need to check patch
files when packages are loaded. There isn't an easy way to do this
at global indexing time without making the FastPackageChecker a lot
slower. This is TBD for a future commit.
- Currently, the same patch can only be used one way in a package. That
is, if it appears twice with different level/working_dir settings,
bad things will happen. There's no package that current uses the
same patch two different ways, so we've punted on this as well, but
we may need to fix this in the future by moving a lot of the metdata
(level, working dir) to the spec, and *only* caching sha256sums in
the PatchCache. That would require some much more complicated tweaks
to the Spec, so we're holding off on that til later.
- This required patches to be refactored somewhat -- the difference
between a UrlPatch and a FilePatch is still not particularly clean.
d3ee6c977b