shell.system() hangs executing Python

[davidm-ro]

python-hanging.zip

See the attached sample Train script for a repro (macOS 15.5, using Python 3.11.4.)

Both these commands will never return and you need to press Ctrl+C to terminate the train script:

shell.system("python3 -c \"print('Hello World')\"", ".");

shell.system("python3 test.py --validate-only", ".");

Expected:

Both those print 'Hello world' and train moves on.

Observed:

You'll see the following printed to console, and nothing else. You'll need to press Ctrl+C to continue.

  shell.system()(python3 -c "print('Hello World')" WD: /Users/work/...) { ...

and the same behaviour for the second one too.

Files

I can't attach train or Python files, so they are:

python-hanging.train:

// Bug Report: shell.system() hangs when executing Python scripts
// 
// Expected: Python script should execute and return output
// Actual: shell.system() hangs indefinitely when calling Python scripts
// 
// This affects any Python script execution, making it impossible to use
// Python-based systems with Train.

log("Testing simple Python command...");
try {
    var result = shell.system("python3 -c \"print('Hello World')\"", ".");
    log("Result: " + result);
} catch (e) {
    log("Error: " + e);
}

log("Testing Python script file...");
try {
    var result = shell.system("python3 test.py --validate-only", ".");
    log("Result: " + result);
} catch (e) {
    log("Error: " + e);
}

log("Test completed - if you see this, the bug was fixed");

and test.py:

#!/usr/bin/env python3

def main():
    print("Hello, World!")

if __name__ == "__main__":
    main()