refactor(core): Replace pickle with JSON serialization in native Python runner (#19123)

packages/@n8n/task-runner-python/src/task_executor.py

@@ -6,7 +6,6 @@ import json
 import os
 import sys
 import tempfile
-import pickle
 
 from src.errors import (
     TaskResultMissingError,
@@ -27,7 +26,7 @@ from typing import Any, Set
 from multiprocessing.context import SpawnProcess
 
 MULTIPROCESSING_CONTEXT = multiprocessing.get_context("spawn")
-MAX_PRINT_STATEMENTS_ALLOWED = 100
+MAX_PRINT_ARGS_ALLOWED = 100
 
 PrintArgs = list[list[Any]]  # Args to all `print()` calls in a Python code task
 
@@ -105,8 +104,8 @@ class TaskExecutor:
 
             result_file = returned["result_file"]
             try:
-                with open(result_file, "rb") as f:
-                    result = pickle.load(f)
+                with open(result_file, "r", encoding="utf-8") as f:
+                    result = json.load(f)
             finally:
                 os.unlink(result_file)
 
@@ -227,9 +226,13 @@ class TaskExecutor:
         queue: multiprocessing.Queue, result: list[Any], print_args: PrintArgs
     ):
         with tempfile.NamedTemporaryFile(
-            mode="wb", delete=False, prefix="n8n_result_"
+            mode="w",
+            delete=False,
+            prefix="n8n_result_",
+            suffix=".json",
+            encoding="utf-8",
         ) as f:
-            pickle.dump(result, f)
+            json.dump(result, f, default=str, ensure_ascii=False)
             result_file = f.name
 
         print_args_to_send = TaskExecutor._truncate_print_args(print_args)
@@ -302,13 +305,13 @@ class TaskExecutor:
     def _truncate_print_args(print_args: PrintArgs) -> PrintArgs:
         """Truncate print_args to prevent pipe buffer overflow."""
 
-        if not print_args or len(print_args) <= MAX_PRINT_STATEMENTS_ALLOWED:
+        if not print_args or len(print_args) <= MAX_PRINT_ARGS_ALLOWED:
             return print_args
 
-        truncated = print_args[:MAX_PRINT_STATEMENTS_ALLOWED]
+        truncated = print_args[:MAX_PRINT_ARGS_ALLOWED]
         truncated.append(
             [
-                f"[Output truncated - {len(print_args) - MAX_PRINT_STATEMENTS_ALLOWED} more print statements]"
+                f"[Output truncated - {len(print_args) - MAX_PRINT_ARGS_ALLOWED} more print statements]"
             ]
         )