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fix(engine): add cross-process merge guard to prevent concurrent merges

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Multiple engine processes (dashboard + serve) share the same SQLite database
but each has its own in-memory merge queue. Without a cross-process check,
two processes can start merging different tasks simultaneously.

Added store.getActiveMergingTask() as a DB-level check before any merge
starts. The drainMergeQueue defers with pollIntervalMs delay, and both
aiMergeTask and processPullRequestMergeTask have safety-net checks.
Also moved stale merge status cleanup to run regardless of autoMerge setting.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
gsxdsm
2026-04-13 20:21:58 -07:00
parent 42c25a0fab
commit c430f95c1d
7 changed files with 70 additions and 3 deletions
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38
packages/engine/src/project-engine.ts
View File

@@ -471,6 +471,36 @@ export class ProjectEngine {
}
const settings = await store.getSettings();
// Cross-process guard: check if another process is already merging a
// task for this project. The in-memory mergeQueue serializes within
// this process, but multiple processes (e.g. dashboard + serve) share
// the same SQLite database and can race.
const activeMergingTask = store.getActiveMergingTask(taskId);
if (activeMergingTask) {
const retryMs = settings.pollIntervalMs ?? 15_000;
runtimeLog.log(
`Merge deferred for ${taskId} — ${activeMergingTask} is already merging (cross-process guard, retry in ${retryMs / 1000}s)`,
);
// Temporarily remove the manual resolver so the finally block
// doesn't prematurely resolve it. The re-enqueue will restore it.
if (manualResolver) {
this.manualMergeResolvers.delete(taskId);
}
// Re-queue after the poll interval so we retry once the other merge finishes
setTimeout(() => {
if (this.shuttingDown) {
manualResolver?.reject(new Error("Engine shutting down"));
return;
}
if (manualResolver) {
this.manualMergeResolvers.set(taskId, manualResolver);
}
this.internalEnqueueMerge(taskId);
}, retryMs);
continue;
}
const mergeStrategy = this.options.getMergeStrategy?.(settings) ?? "direct";
if (mergeStrategy === "pull-request" && this.options.processPullRequestMerge) {
@@ -679,14 +709,13 @@ export class ProjectEngine {
private async startupMergeSweep(store: TaskStore): Promise<void> {
try {
const settings = await store.getSettings();
if (!settings.autoMerge) return;
const tasks = await store.listTasks({ column: "in-review" });
// Clear stale "merging"/"merging-pr" statuses left by a prior crash.
// No merge is actually running at startup, so any task still marked
// as merging is a leftover from a previous engine lifecycle.
// This runs unconditionally (regardless of autoMerge setting) because
// stale statuses block manual merges too.
const staleStatuses = new Set(["merging", "merging-pr"]);
for (const t of tasks) {
if (t.status && staleStatuses.has(t.status)) {
@@ -697,6 +726,9 @@ export class ProjectEngine {
}
}
const settings = await store.getSettings();
if (!settings.autoMerge) return;
const eligible = tasks.filter((t) => this.canMergeTask(t as any));
if (eligible.length > 0) {
runtimeLog.log(`Auto-merge startup sweep: enqueueing ${eligible.length} task(s)`);