fix(dev): ignore invalid backend pid files

scripts/dev-process.sh

@@ -35,6 +35,10 @@ is_running() {
   local pid
   pid="$(cat "$pid_file" 2>/dev/null || true)"
   [[ "$pid" =~ ^[0-9]+$ ]] || return 1
+  (( pid > 1 )) || {
+    rm -f "$pid_file"
+    return 1
+  }
 
   if kill -0 "$pid" 2>/dev/null; then
     return 0

scripts/tests/dev-process-test.sh

@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+DEV_PROCESS="$REPO_ROOT/scripts/dev-process.sh"
+TMP_DIR="$(mktemp -d)"
+PID_FILE="$TMP_DIR/process.pid"
+LOG_FILE="$TMP_DIR/process.log"
+
+cleanup() {
+  bash "$DEV_PROCESS" stop --pid-file "$PID_FILE" >/dev/null 2>&1 || true
+  rm -rf "$TMP_DIR"
+}
+trap cleanup EXIT
+
+echo "0" >"$PID_FILE"
+if bash "$DEV_PROCESS" status --pid-file "$PID_FILE" >/dev/null 2>&1; then
+  echo "expected PID 0 to be treated as not running" >&2
+  exit 1
+fi
+
+if [[ -f "$PID_FILE" ]]; then
+  echo "expected invalid PID file to be removed" >&2
+  exit 1
+fi
+
+bash "$DEV_PROCESS" start \
+  --pid-file "$PID_FILE" \
+  --log-file "$LOG_FILE" \
+  --cwd "$REPO_ROOT" \
+  -- /bin/sh -lc 'sleep 30'
+
+bash "$DEV_PROCESS" status --pid-file "$PID_FILE" >/dev/null
+
+bash "$DEV_PROCESS" stop --pid-file "$PID_FILE"
+
+if [[ -f "$PID_FILE" ]]; then
+  echo "expected PID file to be removed after stop" >&2
+  exit 1
+fi