From ce6c4b89404fb11d61d0deffc1891f5d68c4b0b3 Mon Sep 17 00:00:00 2001
From: "sonika.rathi" <sonika.rathi@espressif.com>
Date: Tue, 7 Jul 2026 09:41:10 +0200
Subject: [PATCH] fix(storage): stabilize parttool pytest serial handoff

---
 .../parttool/pytest_parttool_example.py       | 26 +++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/examples/storage/parttool/pytest_parttool_example.py b/examples/storage/parttool/pytest_parttool_example.py
index 567329a4092..999c6ac4552 100644
--- a/examples/storage/parttool/pytest_parttool_example.py
+++ b/examples/storage/parttool/pytest_parttool_example.py
@@ -1,8 +1,10 @@
-# SPDX-FileCopyrightText: 2022-2025 Espressif Systems (Shanghai) CO LTD
+# SPDX-FileCopyrightText: 2022-2026 Espressif Systems (Shanghai) CO LTD
 # SPDX-License-Identifier: Unlicense OR CC0-1.0
+import logging
 import os
 import subprocess
 import sys
+import time
 
 import pytest
 from pytest_embedded import Dut
@@ -19,12 +21,32 @@ def test_examples_parttool(dut: Dut) -> None:
     # Close connection to DUT
     dut.serial.close()
 
+    # Allow the OS to fully release the serial port. pytest-embedded's
+    # QueueFeederThread may still hold the port FD when close() returns.
+    time.sleep(2)
+
     # Run the example python script
     idf_path = os.getenv('IDF_PATH')
     assert idf_path is not None
     script_path = os.path.join(idf_path, 'examples', 'storage', 'parttool', 'parttool_example.py')
     binary_path = os.path.join(dut.app.binary_path, 'parttool.bin')
-    subprocess.check_call([sys.executable, script_path, '--binary', binary_path, '--port', dut.serial.port])
+
+    # Retry the subprocess to handle transient serial port contention.
+    # parttool_example.py opens the serial port independently via esptool,
+    # and may fail if pytest-embedded's QueueFeederThread has not fully
+    # released the port file descriptor yet.
+    last_err = None
+    for attempt in range(3):
+        try:
+            subprocess.check_call([sys.executable, script_path, '--binary', binary_path, '--port', dut.serial.port])
+            break
+        except subprocess.CalledProcessError as e:
+            last_err = e
+            logging.warning('parttool subprocess attempt %d/3 failed: %s', attempt + 1, e)
+            time.sleep(3)
+    else:
+        assert last_err is not None
+        raise last_err
 
     # following tests check the external interface (parsing) of the parttool commands
     with open('custom.bin', 'wb') as f: