std_output / std_error is not always captured as expected

[ttytm]

Describe the bug

I can't get the expected output of some system commands whose output I want to reuse after executing them in a V program.

I'm running into this when using os.execute or using an os.Process.

Reproduction Steps

• V on Windows

  // main.v
  import os
  
  println(os.execute('fc /lnwt mod.txt mod2.txt').output) // Prints a blank line.
  // os.system('fc /lnwt mod.txt mod2.txt') // Results in the correct output in the terminal.

• python example

  # main.py
  import subprocess
  
  def run_fc(file1, file2):
     cmd = f'fc /lnwt {file1} {file2}'
     result = subprocess.run(cmd, stderr=subprocess.STDOUT, stdout=subprocess.PIPE)
     return result.stdout.decode()
  
  output = run_fc('mod.txt', 'mod2.txt')
  print(output) # Prints the expected output.

• other V example (not limited to windows):

  println(os.execute('${@VEXE} -prod run ${@VEXEROOT}/examples/hello_world.v').output)
  /*
  ❯ v run main.v
  Hello, World!
  
  */
  
  os.system('${@VEXE} -prod run ${@VEXEROOT}/examples/hello_world.v')
  /*
  ❯ v run main.v
  Note: building an optimized binary takes much longer. It shouldn't be used with `v run`.
  Use `v run` without optimization, or build an optimized binary with -prod first, then run it separately.
  Hello, World!
  */

Expected Behavior

Full std_output and std_error in output

Current Behavior

No or limited string in output.

Possible Solution

No response

Additional Information/Context

No response

V version

weekly.2024.18.2

Environment details (OS name and version, etc.)

x64 linux, windows 11 VM

Note

You can use the 👍 reaction to increase the issue's priority for developers.

Please note that only the 👍 reaction to the issue itself counts as a vote.
Other reactions and those to comments will not be taken into account.

[spytheman]

Try reverting c7fb755 locally, to see if that will help?

It is a recent change to os.execute .

[spytheman]

Although c7fb755 was in vlib/os/os_nix.c.v, and you are reporting it for windows 🤔 .
Perhaps we should investigate the vlib/os/os_windows.c.v version more instead.

[spytheman]

Does os.raw_execute work?

[ttytm]

Thanks for looking into it @spytheman.

Can't get it working when reverting.

raw_execute doesn't work either. execute is very close to raw_execute on windows

v/vlib/os/os_windows.c.v

Lines 289 to 297 in 58527cc

	pub fn execute(cmd string) Result {
	if cmd.contains(';') || cmd.contains('&&') || cmd.contains('||') || cmd.contains('\n') {
	return Result{
	exit_code: -1
	output: ';, &&, || and \\n are not allowed in shell commands'
	}
	}
	return unsafe { raw_execute(cmd) }
	}