OpenOCD not starting since Python Platformio process spawn fails

[mhaberler]

Platform: MacOS M1, Vscode
Arduino 3.2 rc2

had the following situation several times, did not see a clear pattern why (it's not Arduino versions):

• cd to the project dir in terminal
• start VSCode with code .
• build/flash works perfectly fine
• starting debug session - Debug Console shows: 'Could not start debugger process > Error: spawn platformio ENOENT'

It turns out that if you activate the pio python environment before starting Vscode with code ., then debugging works fine

NB this has no effect on other aspects of the build - all working fine despite NOT activating the pio Python environment

MacBookPro networking/cores3-read-qrcode logcanvas $ pio
zsh: command not found: pio
MacBookPro networking/cores3-read-qrcode logcanvas $ source /Users/mah/.platformio/penv/bin/activate
(penv) MacBookPro networking/cores3-read-qrcode logcanvas $ pio
Usage: pio [OPTIONS] COMMAND [ARGS]...

Options:
  --version          Show the version and exit.
...
  upgrade   Upgrade PlatformIO Core to the latest version
(penv) MacBookPro networking/cores3-read-qrcode logcanvas $ code .

now starting a debug session works fine, even with latest 3.2rc2

TLDR; activate the platformio Python environment before starting VSCode

Michael

[Jason2866]

Thx a lot for this finding. Will investigate how to implement the activating of the pio python environment without doing harm elsewhere ;-)

[Jason2866]

Honestly currently i have no idea to fix this nice without (ugly) side effects. The Python process spawn needs system env var set to work. Dont want to modify the system env, which is a can of worms to set for all platforms and unset when closing VSC.
Another workaround is to install Platformio in the default system Python. For calling the Debugger (OpenOCD) it is working too to have a Platformio version which is in path which needs just be done one time.

[mhaberler]

not a big issue as there is a workaround

I'm willing to try a few things like Python Environments on VSCode

how would I install pioarduino from the command line?

[Jason2866]

We both use a Apple Silicon Mac so this should work

pip install -U https://github.com/Jason2866/platformio-core/archive/refs/tags/v6.1.18.zip --break-system-packages

[mhaberler]

will report

[mhaberler]

semi-related: it seems the MacOS Python version must be the 3.11 Framework version (whose install package is not online anymore on python.org)

I tried the 3.13 Framework and headed straight to the pits

[mhaberler]

with the activate the platformio Python environment before starting VSCodeworkaround the first debug session also properly downloads [email protected] and debugging works

[Jason2866]

Using python v3.13 with Mac (and in CI runs) works without issues.

[mhaberler]

do you mean v3.13 installed as default Python (Framework)? this is after which I got stuck

and afaict, the pioarduino plugin then installs its own version anyway?

[Jason2866]

Can't reproduce. Works when system uses 3.13 and/ or Platformio python env is 3.13
Or do I misunderstand you and OpenOCD starts correctly with Python v3.9 (without the workaround)?

[mhaberler]

no, that was 3.11

I'll dump 3.11 and switch to 3.13m long overdue anyway
Time machine will save me just in case ;)

[Jason2866]

It is a strange issue. This simple test sketch does not show the error. Debugger starts correctly.
https://github.com/Jason2866/test-pio-debug

[mhaberler]

I tried your repo

first, it initially did start the debugger

it did not stop at setup - however, with tbreak app_main it stops there (old but unrelated)
also old but unrelated: trying to terminate a stuck debug session may leave Python instances hanging in the background
example after exiting VSCode (pretty sure this is a MacOS only issue):

MacBookPro networking/test-pio-debug main $ ps -ax |grep Pyth
29704 ??         0:54.29 /Library/Frameworks/Python.framework/Versions/3.13/Resources/Python.app/Contents/MacOS/Python /Users/mah/.platformio/penv/bin/platformio debug -e esp32s3 --load-mode manual --interface gdb --interpreter=mi2 -q

I also noticed if you change the VSCode profile the spawn error can be made to reappear

I had some success by wiping .vscode and starting over

the causal chain is still unclear to me

[Jason2866]

I think the issue is caused by not activating the Python venv. It looks this works most of the time.
But this is not the way a Python venv should be used. My googling all ended that this error ("spawn") is typical for an not activated Python env. More precisely the not set PATH env variable. In my tests it was enough to set the PATH env to the venv Python to make the error go away. Using a Python venv without activating seems to work most of the time... It is a Platformio concept design bug. Since it is horrible to implement to activate and deactivate a Python venv correctly for all OS i leave this faulty behaviour as it is.

TLDR The Python venv needs to be activated to use the Debugger.