fix(session): guard fallback lock cleanup with reentrancy check

Oracle Public Cloud User · Oracle Public Cloud User · commit 9851714a9b6a · 2026-06-12T04:28:51.000Z
The original fallback unconditionally force-removed the lock file
whenever pid matched, which broke reentrant lock semantics — the
first release in a reentrant pair would remove the file while
another holder still expected it to exist.

Now checks sessionLockHeldByThisProcess before the fallback cleanup.
If any reentrant holder remains, the lock file is preserved as
sidecar-lock intends.
diff --git a/src/agents/session-write-lock.ts b/src/agents/session-write-lock.ts
@@ -991,12 +991,14 @@ export async function acquireSessionWriteLock(params: {
       const release = async () => {
         await innerRelease();
         // Fallback cleanup: if sidecar-lock's removeLockIfUnchanged failed
-        // due to snapshot mismatch, force-remove the lock file if we still
-        // own it (pid matches current process).
+        // due to snapshot mismatch, force-remove the lock file if no
+        // reentrant holder remains and the file still matches our pid.
         try {
-          const payload = await readLockPayload(lockPath);
-          if (payload?.pid === process.pid) {
-            await fs.rm(lockPath, { force: true });
+          if (!sessionLockHeldByThisProcess(normalizedSessionFile)) {
+            const payload = await readLockPayload(lockPath);
+            if (payload?.pid === process.pid) {
+              await fs.rm(lockPath, { force: true });
+            }
           }
         } catch {
           // Best-effort fallback on filesystem errors.
