The change to use `builtins.storePath` was good - for when the store
path *is* already part of the nix store. In all my tests so far, that
was already the case, because I was iterating on the solution and the
Eval results stayed the same.
But when this is run on a entirely new commit, these the values for
`afterDir` and `combinedDir` are *not* in the store, yet. As part of
running `eval.full` on a new commit they will be created. `eval.full` is
linked up, so that the values passed around there will actually be
derivations, which might not be realized, yet.
Checking whether the input is a path or not fixes this for both cases.
Due to how we pass in existing store paths via CLI arguments for the
diff and combine scripts, Nix didn't register a dependency on the store
paths properly. This meant that some of the derivations that were built,
didn't have the right store paths made available in the sandbox -
leading to all kinds of "not found" errors.
We worked around this in CI by resolving the symlinks to the nix store
beforehand. We tried to work around this locally by storing the nix
store path in BASELINE, but this didn't fully work. By explicitly
registering these store paths as dependencies, this should work across
the board - without any magic required by the caller.
When a package's attrpath is renamed it is currently treated as a
rebuild, even though the outpath already exists and is already cached.
This also happens when adding new names for packagesets that already
exist, for example when starting to eval `perlPackages` in CI, which is
just the same as `perl540Packages` currently. It would also happen when
`perlPackages` is switched from `perl540Packages` to `perl999Packages`.
Assuming that `perl999Packages` had already been built before, this
doesn't really cause any rebuilds.
This moves the diff of outpaths into the outpaths job, mainly as a
preparation to allow future improvements. For example, this will allow
running the purity release checks only on changed outpaths instead of
the whole eval.
This also removes the inefficiency introduced in the last commit about
uploading the intermediate paths twice. Now, only the diff is passed on.
Also, technically, the diff is now run in parallel across 4 jobs. This
should be *slightly* faster than before, where outpaths from all systems
were combined first and then diffed. It's probably only a few seconds,
though.
