fix(desktop): first Windows update attempt no longer fails on the app's own dying backends (#74805, salvage #78037) - #95313
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…ackend processes (#74805) taskkill /T /F returns when termination is INITIATED, not completed, and the pre-handoff unlock gate only probed the venv hermes.exe shim — which the 'python.exe -m hermes_cli.main serve' backend need not hold at all. The gate could therefore pass on its first iteration with zero dwell while the killed pythons were still unmapping .pyd files; the venv-blocker scan (no liveness filter) then reported those dying processes as holders and aborted the hand-off. Every first update attempt from the footbar failed; the manual retry succeeded because the process table had settled by then. The unlock gate now lives in backend-release-gate.ts (dependency-free, backend-child.ts pattern) and requires BOTH the shim unlocked AND every signalled PID to have actually left the process table; stragglers collected per-pass are killed and join the watch set. On deadline the old shim-only criterion survives as the escape hatch — lingering PIDs past 15s are the venv-blocker re-scan's job. applyUpdates additionally re-scans up to 2x with a 1.5s settle before aborting on 'blocked', so untracked grandchildren an AV driver holds in teardown stop failing the update while a REAL holder still aborts on the third scan. Surgical reapply of PR #78037 fix 1 by @3x3xX3N0N onto the post-#87599 code shape (stopBackendTreesForUpdate extraction, stopSafeBlockers re-scan path). The re-scan settle idea was first submitted by @MaheshBhushan (#74831); the killed-PID tracking seam matches @webtecnica's #74956. Co-authored-by: MaheshBhushan <128616744+MaheshBhushan@users.noreply.github.com> Co-authored-by: webtecnica <75556242+webtecnica@users.noreply.github.com> Co-authored-by: Hermes <hermes@nousresearch.com>
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Summary
The first Windows update attempt from the Desktop no longer fails on the app's own dying backend processes (#74805; salvage of #78037 fix 1 by @3x3xX3N0N, reworked onto current main with his authorship preserved). Fleet relevance (#91277): the Desktop is the fleet's control seat — a first-attempt-always-fails local update poisons every rollout that starts there.
Root cause:
taskkill /T /Freturns when termination is INITIATED, and the pre-handoff unlock gate only probed the venvhermes.exeshim — which thepython.exe -m hermes_cli.main servebackend need not hold at all. The gate passed with zero dwell while killed pythons were still unmapping.pydfiles; the venv-blocker scan (no liveness filter) reported those dying processes as holders and aborted. Every first attempt failed; the manual retry succeeded because the table had settled.Changes
apps/desktop/electron/backend-release-gate.ts(new, dependency-free per thebackend-child.tspattern): the gate now requires BOTH the shim unlocked AND every signalled PID to have actually left the process table; per-pass stragglers are killed and join the watch set; on deadline the old shim-only criterion survives as the escape hatch (lingering residue is the re-scan's job, a REAL holder still fails the shim probe)apps/desktop/electron/main.ts:releaseBackendLockseeds and delegates to the gate;applyUpdatesre-scans up to 2x with a 1.5s settle before aborting onblocked(covers the plain path AND the post-stopSafeBlockerspath)taskkill, realprocess.kill(pid,0)probe)Attribution: @3x3xX3N0N's design (exit-wait + re-scan dwell, #78037 fix 1); re-scan settle first submitted by @MaheshBhushan (#74831); killed-PID tracking seam matches @webtecnica's #74956 — both credited via Co-authored-by.
Validation
tsc -p tsconfig.jsoncleanLive repro: windows-latest — before: with the merge-base shim-only gate the #74805 shape passes the gate at t=0 while a real killed PID is still enumerable (contract tests fail proving it); after: the gate dwells until the PID genuinely leaves the live process table (9/9). Ephemeral single-use lane per the live-repro-gate rule; no workflow files in this diff.
Fixes #74805. Closes out #78037 fix 1; supersedes #74831 and #74956 (credit above).
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