Symptom
A session only mints its own worktree when another live session already claims the checkout. Two sessions started at nearly the same time both observe the checkout as unclaimed and both run directly on the shared primary working tree, so their edits can collide. Whether an otherwise identical launch lands on an isolated worktree or the primary checkout depends purely on registry timing — the same command can report either worktree: .graff/worktrees/... or no worktree at all.
Root cause
src/session_start.zig:145 calls task_workspace.maybeAutoIsolate(...) during boot.shouldAutoIsolate (src/task_workspace.zig:64-67) gates entirely on claimed, which comes from checkoutClaimed (src/task_workspace.zig:307) — documented read-only: // Read-only: does not announce.- This session's own presence record is written much later, in
presence.announce (src/session_run.zig:365).
The decision is therefore check-then-mint across processes with no lock and no self-claim: every session started inside that window sees "unclaimed" and skips isolation.
Fix
Take the claim before deciding: announce (atomically register-and-check under the registry) first, then mint the worktree if the checkout is contended — so the check and the mint cannot interleave across processes.
Symptom
A session only mints its own worktree when another live session already claims the checkout. Two sessions started at nearly the same time both observe the checkout as unclaimed and both run directly on the shared primary working tree, so their edits can collide. Whether an otherwise identical launch lands on an isolated worktree or the primary checkout depends purely on registry timing — the same command can report either
worktree: .graff/worktrees/...or no worktree at all.Root cause
src/session_start.zig:145callstask_workspace.maybeAutoIsolate(...)during boot.shouldAutoIsolate(src/task_workspace.zig:64-67) gates entirely onclaimed, which comes fromcheckoutClaimed(src/task_workspace.zig:307) — documented read-only:// Read-only: does not announce.presence.announce(src/session_run.zig:365).The decision is therefore check-then-mint across processes with no lock and no self-claim: every session started inside that window sees "unclaimed" and skips isolation.
Fix
Take the claim before deciding: announce (atomically register-and-check under the registry) first, then mint the worktree if the checkout is contended — so the check and the mint cannot interleave across processes.