A snapshot: read at commit 707a04c7ce8 on 2026-10-18T00:06:01Z by majordomus 0.29.0. Nothing on this page is read again. See it live

I2714

One build directory never serves two worktrees' jobs at once

Where it stands

Objective: Prevent a build directory set through CARGO_BUILD_BUILD_DIR from being used by jobs of two different worktrees at the same time, so that one job's build cannot replace the artifacts another job is testing.
Why: 2026-10-14 ~17:30Z: the rust job judging I1501 ran in the private build directory b6-zeta while a landing chain of another worktree and an agent built there too; about 600 doctests failed with \"no such file ... libmajordomus_cli-8669a524ae357c6a.rlib\" and projection-closure \"could not answer\". None of it was the head's defect; the 40-minute job had to be rerun. ADR 0139 keys the default build directory per worktree, but an exported CARGO_BUILD_BUILD_DIR overrides it for every worktree that inherits it.
Now: mj_cargo_bounded waits on cargo's lock and falls back to a private directory only when the shared one is busy beyond a minute; an explicitly exported directory used by two worktrees is accepted silently.
Wanted: A build records which worktree holds its build directory while it runs; a build from a different worktree that finds the directory held refuses, or moves to a directory of its own, and says so, before it compiles anything.
Done when: unknown: the record declares no `completion`
Risk: unknown: the record declares no `risk`

Two worktrees building with the same CARGO_BUILD_BUILD_DIR at once: the second refuses or relocates with a line naming the holder
One worktree's repeated builds in its own directory are unaffected

Touches: lib/rust_bin.shdocs/DEVELOPMENT_RUNTIME.md.ai/repo/adrs/0139-*.mdtest/cases
Not: unknown: the record declares no `non_scope`
Depends on: none
Priority: p1
Profile: implementation
Parallel safe: true
Owner: unknown: the record declares no `owner`

Adapter: scripts/github-sync
Repository: unknown: the derived plan's header carries no repository
External issue: unknown: a live GitHub state; this executable makes no network call, so only `scripts/github-sync --check` can answer it
State there: unknown: a live GitHub state; this executable makes no network call, so only `scripts/github-sync --check` can answer it

Level	Code	Message	Reproduce
WARN	`scope_conflict`	shares test/cases with I2716; they may not run concurrently	`majordomus plan validate`
WARN	`scope_conflict`	shares test/cases with I2717; they may not run concurrently	`majordomus plan validate`
WARN	`scope_conflict`	shares test/cases with I2718; they may not run concurrently	`majordomus plan validate`
WARN	`scope_conflict`	shares test/cases with I2720; they may not run concurrently	`majordomus plan validate`
WARN	`scope_conflict`	shares test/cases with I2723; they may not run concurrently	`majordomus plan validate`
WARN	`scope_conflict`	shares docs/DEVELOPMENT_RUNTIME.md with I2731; they may not run concurrently	`majordomus plan validate`
WARN	`scope_conflict`	shares test/cases with I2734; they may not run concurrently	`majordomus plan validate`
WARN	`scope_conflict`	shares test/cases with I2740; they may not run concurrently	`majordomus plan validate`
WARN	`scope_conflict`	shares test/cases with I2742; they may not run concurrently	`majordomus plan validate`
WARN	`scope_conflict`	shares test/cases with I2747; they may not run concurrently	`majordomus plan validate`
WARN	`scope_conflict`	shares test/cases with I2760; they may not run concurrently	`majordomus plan validate`
WARN	`scope_conflict`	shares test/cases with I2786; they may not run concurrently	`majordomus plan validate`