This workstation configures ONE Cargo target outside the checkouts for every
worktree below the project directory. A build in any worktree therefore
replaced the `qbz` another worktree had just built: a parallel session's
release build in its own worktree replaced the binary under test in the
main one.
scripts/qt-target.py now decides where builds go. When the target Cargo
resolves lies outside the worktree and nothing pins it (CARGO_TARGET_DIR or
CARGO_BUILD_TARGET_DIR), the worktree builds in its own sibling directory,
`<target>-worktrees/<worktree>`; rebuilding the same worktree still replaces
its own binary. Cargo's default target inside the checkout (macOS, CI,
Windows) and explicit overrides are untouched, and no machine path is
committed. Two checkouts that share a directory name get a stable suffix
instead of one target.
qt-run.sh, the runtime gate and direct qt-cargo.py builds and tests all use
it. qt-run.sh prints the target and the binary path, and re-points
crates/target after each successful build, never over a real directory.
The aarch64 scripts build into and install from the same target, and the
qbzd acceptance script names the build command that lands its binary there.
The first build of a profile in a new worktree target is seeded from the
shared target with copy-on-write clones, skipping incremental caches:
Cargo rewrites moved build-script paths through root-output
(custom_build.rs, "rewrite paths if the target directory has been moved"),
so unchanged crates are not compiled again and no data is duplicated.
Without clone support nothing is copied and Cargo builds from scratch.
The resolution and shortcut handling start from the uncommitted draft in
the build-storage-layout worktree. Verified on the main worktree: seeded
from the shared release target, Cargo found everything fresh in two
seconds, and crates/target now points at the worktree's own target. 33
build-gate tests cover derivation, overrides, name collisions, linking,
seeding and the runner end to end.
cc
vicrodh
e8f4dd4aa3