std.Build.Step.Run: inherit build runner cwd

Right now, if you override the build root with `--build-root`, then
`Run` steps can fail to execute because of incorrect path handling in
the compiler: `std.process.Child` gets a cwd-relative path, but also has
its cwd set to the build root. The latter behavior is really weird; it
doesn't match my expectations, nor does it match how we spawn child
`zig` processes. So, this commit makes the child process inherit the
build runner's cwd, as `LazyPath.getPath2` *expects* it to.

After investigating, this behavior dates all the way back to 2017; it
was introduced in 4543413. So, there isn't any clear/documented reason
for this; it should be safe to revert, since under the modern `LazyPath`
system it is strictly a bug AFAICT.
This commit is contained in:
mlugg 2025-05-21 01:45:05 +01:00
parent a63f7875f4
commit fe855691f6
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@ -1334,9 +1334,6 @@ fn spawnChildAndCollect(
var child = std.process.Child.init(argv, arena);
if (run.cwd) |lazy_cwd| {
child.cwd = lazy_cwd.getPath2(b, &run.step);
} else {
child.cwd = b.build_root.path;
child.cwd_dir = b.build_root.handle;
}
child.env_map = run.env_map orelse &b.graph.env_map;
child.request_resource_usage_statistics = true;