From dab2ccb2c34904546da7c7f394b6011017a45fd0 Mon Sep 17 00:00:00 2001
From: Behruz Nassre Esfahani <behruz@gmail.com>
Date: Mon, 20 Jul 2026 17:52:09 -0700
Subject: [PATCH] fix: preserve sandboxed background jobs on EPERM

Treat permission-denied zero-signal probes as evidence that a process exists so the stale-job reaper does not fail live Claude jobs. Add deterministic EPERM and ESRCH coverage.\n\nRefs #79
---
 scripts/lib/process.mjs |  9 +++++----
 tests/process.test.mjs  | 30 ++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/scripts/lib/process.mjs b/scripts/lib/process.mjs
index ba532df..0e91d78 100644
--- a/scripts/lib/process.mjs
+++ b/scripts/lib/process.mjs
@@ -163,11 +163,12 @@ export function validateProcessIdentity(pid, expectedIdentity) {
   }
 }
 
-export function isProcessAlive(pid) {
+export function isProcessAlive(pid, options = {}) {
+  const killImpl = options.killImpl ?? process.kill.bind(process);
   try {
-    process.kill(pid, 0);
+    killImpl(pid, 0);
     return true;
-  } catch {
-    return false;
+  } catch (error) {
+    return error?.code === "EPERM";
   }
 }
diff --git a/tests/process.test.mjs b/tests/process.test.mjs
index b6514b6..07b1ecf 100644
--- a/tests/process.test.mjs
+++ b/tests/process.test.mjs
@@ -324,6 +324,36 @@ describe("isProcessAlive", () => {
     // PID 99999999 is extremely unlikely to exist
     assert.equal(isProcessAlive(99999999), false);
   });
+
+  it("treats EPERM as alive when the sandbox denies the probe", () => {
+    const permissionError = Object.assign(new Error("operation not permitted"), {
+      code: "EPERM",
+    });
+
+    assert.equal(
+      isProcessAlive(12345, {
+        killImpl: () => {
+          throw permissionError;
+        },
+      }),
+      true,
+    );
+  });
+
+  it("treats ESRCH as dead when the process does not exist", () => {
+    const missingError = Object.assign(new Error("no such process"), {
+      code: "ESRCH",
+    });
+
+    assert.equal(
+      isProcessAlive(12345, {
+        killImpl: () => {
+          throw missingError;
+        },
+      }),
+      false,
+    );
+  });
 });
 
 // ---------------------------------------------------------------------------