feat: enhance pre-push error handling and output reporting

bin/pushgate.mjs

@@ -17,7 +17,7 @@ switch (command) {
     process.stdout.write(`${HOOK_PROTOCOL}\n`);
     break;
   case "pre-push":
-    await drainStdin();
+    drainStdin();
     break;
   default:
     fail(command ? `Unsupported Pushgate command: ${command}` : "Missing Pushgate command.");
@@ -28,15 +28,13 @@ function fail(message) {
   process.exitCode = 64;
 }
 
-async function drainStdin() {
-  try {
-    for await (const _chunk of process.stdin) {
-      // Drain Git hook ref updates. Later runner layers will parse this stream.
-    }
-  } catch (error) {
+function drainStdin() {
+  process.stdin.on("error", (error) => {
     const detail = error instanceof Error ? error.message : String(error);
 
     process.stderr.write(`Failed to read pre-push input: ${detail}\n`);
     process.exitCode = 1;
-  }
+  });
+  // Drain Git hook ref updates. Later runner layers will parse this stream.
+  process.stdin.resume();
 }

hook/pre-push

@@ -44,8 +44,16 @@ if [ ! -x "$PUSHGATE_RUNNER" ]; then
   exit 1
 fi
 
-if ! RUNNER_PROTOCOL="$("$PUSHGATE_RUNNER" hook-protocol 2>/dev/null)"; then
+if ! RUNNER_PROTOCOL="$("$PUSHGATE_RUNNER" hook-protocol 2>&1)"; then
   error "Pushgate runner at ${PUSHGATE_RUNNER} could not report its hook protocol."
+  if [ -n "$RUNNER_PROTOCOL" ]; then
+    error "Runner output:"
+    while IFS= read -r line; do
+      error "  $line"
+    done <<EOF
+$RUNNER_PROTOCOL
+EOF
+  fi
   reinstall_hint
   exit 1
 fi

test/hook.test.ts

@@ -81,6 +81,25 @@ test("fails clearly when the runner hook protocol is outdated", async () => {
   });
 });
 
+test("surfaces runner output when the protocol probe cannot execute", async () => {
+  await withHarness(async (harness) => {
+    await harness.installRunnerStub();
+
+    const result = await harness.runHook({
+      env: {
+        PUSHGATE_RUNNER_PROTOCOL_ERROR: "env: node: No such file or directory",
+        PUSHGATE_RUNNER_PROTOCOL_EXIT: "127",
+      },
+      stdin: "",
+    });
+    const output = cleanHookOutput(result);
+
+    assert.equal(result.code, 1, output);
+    assert.match(output, /could not report its hook protocol/);
+    assert.match(output, /env: node: No such file or directory/);
+  });
+});
+
 test("allows a real installed-hook push through the boundary runner", async () => {
   await withHarness(async (harness) => {
     await harness.installRealRunner();

test/support/hook-harness.ts

@@ -95,6 +95,10 @@ case "\${1:-}" in
     if [ "$#" -ne 1 ]; then
       exit 64
     fi
+    if [ "$PUSHGATE_RUNNER_PROTOCOL_EXIT" -ne 0 ]; then
+      printf '%s\\n' "$PUSHGATE_RUNNER_PROTOCOL_ERROR" >&2
+      exit "$PUSHGATE_RUNNER_PROTOCOL_EXIT"
+    fi
     printf '%s\\n' "$PUSHGATE_RUNNER_PROTOCOL"
     ;;
   pre-push)
@@ -312,6 +316,8 @@ function createSandboxEnv(
     PATH: [binDir, ...systemPath].join(delimiter),
     PUSHGATE_RUNNER_EXIT: "0",
     PUSHGATE_RUNNER_PROTOCOL: "1",
+    PUSHGATE_RUNNER_PROTOCOL_ERROR: "",
+    PUSHGATE_RUNNER_PROTOCOL_EXIT: "0",
     PUSHGATE_STUB_DIR: artifactsDir,
     TERM: "dumb",
     XDG_CONFIG_HOME: join(homeDir, ".config"),