* build.zig: introduce `-Dflat` option which makes the installation
match what we want to ship for our download tarballs. This allows
deleting a bunch of shell script logic from the CI.
- for example it puts the executable directly in prefix/zig rather
than prefix/bin/zig and it additionally includes prefix/LICENSE.
* build.zig: by default also install std lib documentation to doc/std/
- this can be disabled by `-Dno-autodocs` similar to how there is
already `-Dno-langref`.
* build.zig: add `std-docs` and `langref` steps which build and install
the std lib autodocs and langref to prefix/doc/std and
prefix/doc/langref.html, respectively.
* std.Build: implement proper handling of `-femit-docs` using the
LazyPath system. This is a breaking change.
- this is a partial implementation of #16351
* frontend: fixed the handling of Autodocs with regards to caching and
putting the artifacts in the proper location to integrate with the
build system.
- closes#15864
* CI: delete the logic for autodocs since it is now handled by build.zig
and is enabled by default.
- in the future we should strive to have nearly all the CI shell
script logic deleted in favor of `zig build` commands.
* CI: pass `-DZIG_NO_LIB=ON`/`-Dno-lib` except for the one command where
we want to actually generate the langref and autodocs. Generating the
langref takes 14 minutes right now (why?!) so we don't want to do that
more times than necessary.
* Autodoc: fixed use of a global variable. It works fine as a local
variable instead.
- note that in the future we will want to make Autodoc run
simultaneously using the job system, but for now the principle of
YAGNI dictates that we don't have an init()/deinit() API and instead
simply call the function that does the things.
* Autodoc: only do it when there are no compile errors
to avoid getting OOM killed. It's been happening regularly recently. We
need to have a high number of GitHub Actions runners simultaneously
active, otherwise the hardware ends up underutilized. But with zig build
running in parallel now, this sometimes results in memory usage spikes
that have been causing the runner to get killed.
This number is the total physical memory (126G) divided by the number of
runners we have active (6).
Zig's build script has several race conditions preventing proper
concurrent builds from working. By using -j1 for now, finishing this
branch (concurrent zig builds) is untangled from the separate problem of
correcting concurrency issues with zig's own build script.
In other words, let's solve one problem at a time.
Override the cache directories because they won't actually help other CI
runs which will be testing alternate versions of zig, and ultimately
would just fill up space on the hard drive for no reason.
In practice we did see one of the CI servers fill up too many files
inside ~/.cache/zig, which caused certain file system operations to
start returning ENOSPC, despite the hard drive having plenty of space
left.
