Stderr empty when calling esptool with subprocess.Popen (ESPTOOL-696)

[Waganama]

Operating System

Python

Esptool Version

V4.6.1

Python Version

Python 3.11

Full Esptool Command Line that Was Run

esptool -p COM9 --chip esp32 read_mac

Esptool Output

STDOUT : b'esptool.py v4.6.1\r\nSerial port COM9\r\nConnecting......................................\r\n\r\nA fatal error occurred: Failed to connect to ESP32: No serial data received.\r\nFor troubleshooting steps visit:

https://docs.espressif.com/projects/esptool/en/latest/troubleshooting.html\r\n'

STDERR : b''

What is the Expected Behaviour?

STDOUT : b'esptool.py v4.6.1\r\nSerial port COM9\r\nConnecting......................................\r\n\r\n

STDERR : b''A fatal error occurred: Failed to connect to ESP32: No serial data received.\r\nFor troubleshooting steps visit:

https://docs.espressif.com/projects/esptool/en/latest/troubleshooting.html\r\n'"

More Information

Hello guys,
I tried to catch esptool error in stderr from subprocess.Popen with the following code :

def read_mac(self, port) :
command = [ESPTOOL_PY, '-p', port, '--chip', 'esp32', 'read_mac']
send_command(command)

def send_command(command: list[str]) :
out = subprocess.Popen([sys.executable] + command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=False)
stdout, stderr = out.communicate()

print(f'STDOUT : {stdout}')
print(f'STDERR : {stderr}')

Thanks for your help :)

Other Steps to Reproduce

No response

[radimkarnis]

Hi @Waganama,
thanks for the ticket!

It will be implemented as a part of the next major release (v5.0) since it is a breaking change for current scripts relying on reading the stdout output.

I will keep this open until then.