# --------------------- DIAGNOSTICS: Prove temp file is created & readable ---------------------
        print("\n--- TEMP FILE DIAGNOSTICS ---")
        print(f"Current working directory: {os.getcwd()}")
        print(f"Temp dir in use: {tempfile.tempdir}")

        if os.path.exists(jcl_path):  # jcl_path is the variable holding your temp file name/path
            print(f"File exists: YES  →  {jcl_path}")
            print(f"File size: {os.path.getsize(jcl_path)} bytes")
            
            # Show basic permissions (octal, e.g. 0o644 = rw-r--r--)
            st = os.stat(jcl_path)
            print(f"Permissions (octal): {oct(st.st_mode & 0o777)}")
            print(f"Owner UID: {st.st_uid} (your user should match os.getuid())")
            
            # Try reading it back to prove readability
            try:
                with open(jcl_path, 'r') as f:
                    content = f.read()
                print("File is readable! First 200 chars of content:")
                print(repr(content[:200]))  # repr() shows escapes/newlines clearly
                print(f"... (total lines: {content.count('\n') + 1})")
            except Exception as e:
                print(f"Read failed: {e}")
        else:
            print("File exists: NO  → something went wrong creating it")
        print("--- END DIAGNOSTICS ---\n")