fix: capture stderr in utils.call when capture_stdout is True (#2076)

cibuildwheel/macos.py

@@ -278,23 +278,23 @@ def setup_python(
     # Apply our environment after pip is ready
     env = environment.as_dictionary(prev_environment=env)
 
-    # check what pip version we're on
-    if not use_uv:
-        assert (venv_bin_path / "pip").exists()
-        call("which", "pip", env=env)
-        call("pip", "--version", env=env)
-        which_pip = call("which", "pip", env=env, capture_stdout=True).strip()
-        if which_pip != str(venv_bin_path / "pip"):
-            msg = "cibuildwheel: pip available on PATH doesn't match our installed instance. If you have modified PATH, ensure that you don't overwrite cibuildwheel's entry or insert pip above it."
-            raise errors.FatalError(msg)
-
     # check what Python version we're on
-    call("which", "python", env=env)
-    call("python", "--version", env=env)
     which_python = call("which", "python", env=env, capture_stdout=True).strip()
+    print(which_python)
     if which_python != str(venv_bin_path / "python"):
         msg = "cibuildwheel: python available on PATH doesn't match our installed instance. If you have modified PATH, ensure that you don't overwrite cibuildwheel's entry or insert python above it."
         raise errors.FatalError(msg)
+    call("python", "--version", env=env)
+
+    # check what pip version we're on
+    if not use_uv:
+        assert (venv_bin_path / "pip").exists()
+        which_pip = call("which", "pip", env=env, capture_stdout=True).strip()
+        print(which_pip)
+        if which_pip != str(venv_bin_path / "pip"):
+            msg = "cibuildwheel: pip available on PATH doesn't match our installed instance. If you have modified PATH, ensure that you don't overwrite cibuildwheel's entry or insert pip above it."
+            raise errors.FatalError(msg)
+        call("pip", "--version", env=env)
 
     config_is_arm64 = python_configuration.identifier.endswith("arm64")
     config_is_universal2 = python_configuration.identifier.endswith("universal2")

cibuildwheel/pyodide.py

@@ -136,22 +136,22 @@ def setup_python(
 
     env = environment.as_dictionary(prev_environment=env)
 
-    # check what pip version we're on
-    assert (venv_bin_path / "pip").exists()
-    call("which", "pip", env=env)
-    call("pip", "--version", env=env)
-    which_pip = call("which", "pip", env=env, capture_stdout=True).strip()
-    if which_pip != str(venv_bin_path / "pip"):
-        msg = "pip available on PATH doesn't match our venv instance. If you have modified PATH, ensure that you don't overwrite cibuildwheel's entry or insert pip above it."
-        raise errors.FatalError(msg)
-
     # check what Python version we're on
-    call("which", "python", env=env)
-    call("python", "--version", env=env)
     which_python = call("which", "python", env=env, capture_stdout=True).strip()
+    print(which_python)
     if which_python != str(venv_bin_path / "python"):
         msg = "python available on PATH doesn't match our venv instance. If you have modified PATH, ensure that you don't overwrite cibuildwheel's entry or insert python above it."
         raise errors.FatalError(msg)
+    call("python", "--version", env=env)
+
+    # check what pip version we're on
+    assert (venv_bin_path / "pip").exists()
+    which_pip = call("which", "pip", env=env, capture_stdout=True).strip()
+    print(which_pip)
+    if which_pip != str(venv_bin_path / "pip"):
+        msg = "pip available on PATH doesn't match our venv instance. If you have modified PATH, ensure that you don't overwrite cibuildwheel's entry or insert pip above it."
+        raise errors.FatalError(msg)
+    call("pip", "--version", env=env)
 
     log.step("Installing build tools...")
     call(

cibuildwheel/util.py

@@ -38,6 +38,7 @@ from platformdirs import user_cache_path
 
 from ._compat import tomllib
 from .architecture import Architecture
+from .errors import FatalError
 from .typing import PathOrStr, PlatformName
 
 __all__ = [
@@ -139,13 +140,32 @@ def call(
     args_ = [str(arg) for arg in args]
     # print the command executing for the logs
     print("+ " + " ".join(shlex.quote(a) for a in args_))
-    kwargs: dict[str, Any] = {}
+    # workaround platform behaviour differences outlined
-    if capture_stdout:
+    # in https://github.com/python/cpython/issues/52803
-        kwargs["universal_newlines"] = True
+    path_env = env if env is not None else os.environ
-        kwargs["stdout"] = subprocess.PIPE
+    path = path_env.get("PATH", None)
-    result = subprocess.run(args_, check=True, shell=IS_WIN, env=env, cwd=cwd, **kwargs)
+    executable = shutil.which(args_[0], path=path)
+    if executable is None:
+        msg = f"Couldn't find {args_[0]!r} in PATH {path!r}"
+        raise FatalError(msg)
+    args_[0] = executable
+    try:
+        result = subprocess.run(
+            args_,
+            check=True,
+            shell=IS_WIN,
+            env=env,
+            cwd=cwd,
+            capture_output=capture_stdout,
+            text=capture_stdout,
+        )
+    except subprocess.CalledProcessError as e:
+        if capture_stdout:
+            sys.stderr.write(e.stderr)
+        raise
     if not capture_stdout:
         return None
+    sys.stderr.write(result.stderr)
     return typing.cast(str, result.stdout)
 
 

cibuildwheel/windows.py

@@ -302,22 +302,22 @@ def setup_python(
     env = environment.as_dictionary(prev_environment=env)
 
     # check what Python version we're on
-    call("where", "python", env=env)
-    call("python", "--version", env=env)
-    call("python", "-c", "\"import struct; print(struct.calcsize('P') * 8)\"", env=env)
     where_python = call("where", "python", env=env, capture_stdout=True).splitlines()[0].strip()
+    print(where_python)
     if where_python != str(venv_path / "Scripts" / "python.exe"):
         msg = "python available on PATH doesn't match our installed instance. If you have modified PATH, ensure that you don't overwrite cibuildwheel's entry or insert python above it."
         raise errors.FatalError(msg)
+    call("python", "--version", env=env)
+    call("python", "-c", "\"import struct; print(struct.calcsize('P') * 8)\"", env=env)
 
     # check what pip version we're on
     if not use_uv:
         assert (venv_path / "Scripts" / "pip.exe").exists()
         where_pip = call("where", "pip", env=env, capture_stdout=True).splitlines()[0].strip()
+        print(where_pip)
         if where_pip.strip() != str(venv_path / "Scripts" / "pip.exe"):
             msg = "pip available on PATH doesn't match our installed instance. If you have modified PATH, ensure that you don't overwrite cibuildwheel's entry or insert pip above it."
             raise errors.FatalError(msg)
-
         call("pip", "--version", env=env)
 
     log.step("Installing build tools...")