This is for bypassing the package manager and directly depending on
another package via the build system. For this to work the anonymous
package must be found on the file system relative to the current
package's build.zig.
These were mostly already using the correct build API. I cleaned up the
code a bit and unconditionally disabled LTO for these tests since that
actually tests the intended behavior better.
CLI tests are now ported over to the new std.Build API and thus work
properly with concurrency.
* add `std.Build.addCheckFile` for creating a
`std.Build.CheckFileStep`.
* add `std.Build.makeTempPath`. This function is intended to be called
in the `configure` phase only. It returns an absolute directory path,
which is potentially going to be a source of API breakage in the
future, so keep that in mind when using this function.
* add `std.Build.CheckFileStep.setName`.
* `std.Build.CheckFileStep`: better error message when reading the
input file fails.
* `std.Build.RunStep`: add a `has_side_effects` flag for when you need
to override the autodetection.
* `std.Build.RunStep`: add the ability to obtain a FileSource for the
directory that contains the written files.
* `std.Build.WriteFileStep`: add a way to write bytes to an arbitrary
path - absolute or relative to the package root. Be careful with this
because it updates source files. This should not be used as part of
the normal build process, but as a utility occasionally run by a
developer with intent to modify source files and then commit those
changes to version control. A file added this way is not available
with `getFileSource`.
* RunStep: ability to set stdin
* RunStep: ability to capture stdout and stderr as a FileSource
* RunStep: add setName method
* RunStep: hash the stdio checks
The problem is that one may execute too many subprocesses concurrently
that, together, exceed an RSS value that causes the OOM killer to kill
something problematic such as the window manager. Or worse, nothing, and
the system freezes.
This is a real world problem. For example when building LLVM a simple
`ninja install` will bring your system to its knees if you don't know
that you should add `-DLLVM_PARALLEL_LINK_JOBS=1`.
In particular: compiling the zig std lib tests takes about 2G each,
which at 16x at once (8 cores + hyperthreading) is using all 32GB of my
RAM, causing the OOM killer to kill my window manager
The idea here is that you can annotate steps that might use a high
amount of system resources with an upper bound. So for example I could
mark the std lib tests as having an upper bound peak RSS of 3 GiB.
Then the build system will do 2 things:
1. ulimit the child process, so that it will fail if it would exceed
that memory limit.
2. Notice how much system RAM is available and avoid running too many
concurrent jobs at once that would total more than that.
This implements (1) not with an operating system enforced limit, but by
checking the maxrss after a child process exits.
However it does implement (2) correctly.
The available memory used by the build system defaults to the total
system memory, regardless of whether it is used by other processes at
the time of spawning the build runner. This value can be overridden with
the new --maxrss flag to `zig build`. This mechanism will ensure that
the sum total of upper bound RSS memory of concurrent tasks will not
exceed this value.
This system makes it so that project maintainers can annotate
problematic subprocesses, avoiding bug reports from users, who can
blissfully execute `zig build` without worrying about the project's
internals.
Nobody's computer crashes, and the build system uses as much parallelism
as possible without risking OOM. Users do not need to unnecessarily
resort to -j1 when the build system can figure this out for them.
* remove std.Build.updateFile. I noticed some people use it from
build.zig (declare phase) when it is intended only for use in the
make phase.
- This also was incorrectly reporting errors with std.log.
* std.Build.InstallArtifactStep
- report better errors on failure
- report whether the step was cached or not
* std.Build.InstallDirStep: report better error on failure
* std.Build.InstallFileStep: report better error on failure
* Eliminate all uses of `std.debug.print` in make() functions, instead
properly using the step failure reporting mechanism.
* Introduce the concept of skipped build steps. These do not cause the
build to fail, and they do allow their dependants to run.
* RunStep gains a new flag, `skip_foreign_checks` which causes the
RunStep to be skipped if stdio mode is `check` and the binary cannot
be executed due to it being a foreign executable.
- RunStep is improved to automatically use known interpreters to
execute binaries if possible (integrating with flags such as
-fqemu and -fwasmtime). It only does this after attempting a native
execution and receiving a "exec file format" error.
- Update RunStep to use an ArrayList for the checks rather than this
ad-hoc reallocation/copying mechanism.
- `expectStdOutEqual` now also implicitly adds an exit_code==0 check
if there is not already an expected termination. This matches
previously expected behavior from older API and can be overridden by
directly setting the checks array.
* Add `dest_sub_path` to `InstallArtifactStep` which allows choosing an
arbitrary subdirectory relative to the prefix, as well as overriding
the basename.
- Delete the custom InstallWithRename step that I found deep in the
test/ directory.
* WriteFileStep will now update its step display name after the first
file is added.
* Add missing stdout checks to various standalone test case build
scripts.
Rework std.Build.Step to have an `owner: *Build` field. This
simplified the implementation of installation steps, as well as provided
some much-needed common API for the new parallelized build system.
--verbose is now defined very concretely: it prints to stderr just
before spawning a child process.
Child process execution is updated to conform to the new
parallel-friendly make() function semantics.
DRY up the failWithCacheError handling code. It now integrates properly
with the step graph instead of incorrectly dumping to stderr and calling
process exit.
In the main CLI, fix `zig fmt` crash when there are no errors and stdin
is used.
Deleted steps:
* EmulatableRunStep - this entire thing can be removed in favor of a
flag added to std.Build.RunStep called `skip_foreign_checks`.
* LogStep - this doesn't really fit with a multi-threaded build runner
and is effectively superseded by the new build summary output.
build runner:
* add -fsummary and -fno-summary to override the default behavior,
which is to print a summary if any of the build steps fail.
* print the dep prefix when emitting error messages for steps.
std.Build.FmtStep:
* This step now supports exclude paths as well as a check flag.
* The check flag decides between two modes, modify mode, and check
mode. These can be used to update source files in place, or to fail
the build, respectively.
Zig's own build.zig:
* The `test-fmt` step will do all the `zig fmt` checking that we expect
to be done. Since the `test` step depends on this one, we can simply
remove the explicit call to `zig fmt` in the CI.
* The new `fmt` step will actually perform `zig fmt` and update source
files in place.
std.Build.RunStep:
* expose max_stdio_size is a field (previously an unchangeable
hard-coded value).
* rework the API. Instead of configuring each stream independently,
there is a `stdio` field where you can choose between
`infer_from_args`, `inherit`, or `check`. These determine whether the
RunStep is considered to have side-effects or not. The previous
field, `condition` is gone.
* when stdio mode is set to `check` there is a slice of any number of
checks to make, which include things like exit code, stderr matching,
or stdout matching.
* remove the ill-defined `print` field.
* when adding an output arg, it takes the opportunity to give itself a
better name.
* The flag `skip_foreign_checks` is added. If this is true, a RunStep
which is configured to check the output of the executed binary will
not fail the build if the binary cannot be executed due to being for
a foreign binary to the host system which is running the build graph.
Command-line arguments such as -fqemu and -fwasmtime may affect
whether a binary is detected as foreign, as well as system
configuration such as Rosetta (macOS) and binfmt_misc (Linux).
- This makes EmulatableRunStep no longer needed.
* Fix the child process handling to properly integrate with the new
bulid API and to avoid deadlocks in stdout/stderr streams by polling
if necessary.
std.Build.RemoveDirStep now uses the open build_root directory handle
instead of an absolute path.
This makes progress be exposed to the top-level caller of update().
I tossed in a bonus change: when the `zig build` subcommand sees exit
code 2, it omits the "following command failed" line, and the build
runner uses exit code 2 when there are compile errors. This tidies up
the output on build failure by a little bit.
