Having the matrix of test targets for incremental compilation in the
individual test manifests has turned out to be inconvenient for a few
reasons: the tests are almost certain to accidentally get out of sync,
disabling targets entirely is annoying to do, and incr-check needs to
take care to print the target in all error messages (which currently
does not always happen).
If I recall correctly, I originally designed it this way because it
allows targets to be disabled at the granularity of individual tests,
but there's an easier approach to that: just let a test manifest that it
should be *skipped* on a certain target! As skipping is the rare case,
and also the case you want readers to notice, it makes sense for *it* to
be explicitly specified, like how unit tests use `error.SkipZigTest`.
So, `incr-check` no longer runs through a list of targets specified in
the manifest. Instead, it accepts (and, in fact, requires) a single
target on the command line, and runs the test for that specific target.
If the file contains a `#skip_target` directive for that target, then
`incr-check` exits immediately, so we can still disable targets at
individual test granularity, but you can also disable a target for all
tests by just commenting it out of the matrix in `test/tests.zig`.
As a nice bonus, this also allows the build system to run different
incremental test targets in parallel, because the targets are now
different steps.
This definitely seems like a better way to split the work between the
build system and incr-check---sorry for getting this wrong initially!
These all pass now! I have also removed the warning about the LLVM
backend not supporting incremental compilation; I expect it will work
sort of okay in practice by now.
Matthew Lugg