Fix crashes when warnings would be produced by running Python

Fixes python-poetry#6664

src/poetry/utils/env.py

@@ -1476,7 +1476,13 @@ def run_pip(self, *args: str, **kwargs: Any) -> int | str:
 
  def run_python_script(self, content: str, **kwargs: Any) -> int | str:
  return self.run(
- self._executable, "-I", "-W", "ignore", "-", input_=content, **kwargs
+ self._executable,
+ "-W",
+ "ignore",
+ "-",
+ input_=content,
+ stderr=subprocess.DEVNULL,
+ **kwargs,
  )
 
  def _run(self, cmd: list[str], **kwargs: Any) -> int | str:
@@ -1486,6 +1492,7 @@ def _run(self, cmd: list[str], **kwargs: Any) -> int | str:
  call = kwargs.pop("call", False)
  input_ = kwargs.pop("input_", None)
  env = kwargs.pop("env", dict(os.environ))
+ stderr = kwargs.pop("stderr", subprocess.STDOUT)
 
  try:
  if self._is_windows:
@@ -1501,18 +1508,16 @@ def _run(self, cmd: list[str], **kwargs: Any) -> int | str:
  output = subprocess.run(
  command,
  stdout=subprocess.PIPE,
- stderr=subprocess.STDOUT,
+ stderr=stderr,
  input=encode(input_),
  check=True,
  **kwargs,
  ).stdout
  elif call:
- return subprocess.call(
- command, stderr=subprocess.STDOUT, env=env, **kwargs
- )
+ return subprocess.call(command, stderr=stderr, env=env, **kwargs)
  else:
  output = subprocess.check_output(
- command, stderr=subprocess.STDOUT, env=env, **kwargs
+ command, stderr=stderr, env=env, **kwargs
  )
  except CalledProcessError as e:
  raise EnvCommandError(e, input=input_)