18ab9f6db2
The linear replay carried each commit's own lineage, so this checkpoint restores the master-owned surfaces the conflicted regions clobbered and migrates branch-owned code to master's post-rebase APIs: - rebuild subprocess-local spawn.ts on master's tree-exit-observer machinery, keeping the branch's win32 childEnv key semantics and the Linux zombie-quiescence probe; the zombie test reaps its survivor directly since a confirmed-absent verdict is a permanent no-more-signals boundary - migrate pty-local test stubs to the Inbox-model Agent interface, Session.create, runnerFailureRules, and the new turn/start payload - implement the seam's resolveExecutable/spawnTerminal abstracts in the new pwsh-local and tool-fs-search test fakes - restore code-runtime, atomic-write, pwsh-local, and app-boot to master's exact content (the net-zero code-runtime churn is pruned from this history) and drop rename-detection graft debris - re-apply the PR's architecture rows and execution-world paragraph, re-record bilingual pairings, regenerate catalogs, and reconcile the lockfile
dsh-atomic-write
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Zero-dependency atomic file replacement shared by file-backed stores that must never leave partial, symlink-hijacked, or wider-than-intended content on disk — the user-settings document (dsh-settings-local) and the credentials store (dsh-credentials-local).
Surface
import { withFileLock, writeFileAtomic } from '@deepseek-ai/dsh-atomic-write'
declare const text: string
declare const render: (previous: string) => string
await writeFileAtomic('/home/u/.dsh/settings.yaml', text, { mode: 0o600 })
// Read-modify-write against the same file from several processes.
await withFileLock('/home/u/.dsh/settings.yaml', async () => {
await writeFileAtomic('/home/u/.dsh/settings.yaml', render(text), { mode: 0o600 })
})
writeFileAtomic commits one already-rendered string. The contract, in the order failures would exploit it:
- Exclusive-create temp (
wx, random suffix): the open refuses to follow a symlink planted at a guessable temp path. - The fresh inode carries
modethrough the rename: replacing a wider-permission file narrows it without a chmod race.modeis required so the permission decision stays visible at every call site (subject to the process umask, like every fresh inode). renamereplaces a symlinked target itself, never writing through to its referent.- Same-directory sibling keeps the rename on one filesystem, so the swap stays atomic.
- Parent directories are created; on any failure the temp is removed and the failure rethrown; readers observe either the old or the new complete content.
withFileLock serializes the writers of one file across processes, for the read-render-commit cycles a bare atomic commit cannot make safe on its own. The lock is a wx-created <filename>.lock sibling, so readers never contend; waiters back off exponentially and fail with a timeout rather than block forever. A contender never removes the existing lock: age cannot distinguish a crashed owner from a paused live writer.
Model Experience
None, as this is a pure filesystem primitive; nothing here reaches a model request.
KV Cache effect
None; nothing here enters a request prefix.
Known Limitations and Deferred Work
- Atomic, not durable — no
fsyncof the file or its directory, so after a crash the rename may be observed unwound. The file-backed stores here re-read and republish on boot, keeping durability the caller's policy. - String content only — no
Bufferor stream form until a consumer needs one. - Orphaned locks require operator recovery — a process that exits while holding the lock can leave the sibling behind. Later writers time out without deleting it; an operator removes it only after verifying that no writer still owns it. File age alone is not safe evidence of abandonment.