Revert "fix(build): set CARGO_TARGET_DIR per package"

src/fromager/vendor_rust.py

@@ -115,18 +115,6 @@ def _detect_rust_build_backend(
     return None
 
 
-def has_rust_build_backend(req: Requirement, project_dir: pathlib.Path) -> bool:
-    """Return ``True`` if the project uses a Rust build backend.
-
-    Checks whether the project's ``pyproject.toml`` declares ``maturin``
-    or ``setuptools-rust`` as its build backend.
-    """
-    pyproject_toml = dependencies.get_pyproject_contents(project_dir)
-    if not pyproject_toml:
-        return False
-    return _detect_rust_build_backend(req, pyproject_toml) is not None
-
-
 def vendor_generic_rust_package(
     req: Requirement,
     manifests: list[pathlib.Path],

src/fromager/wheels.py

@@ -30,7 +30,6 @@
     requirements_file,
     resolver,
     sbom,
-    vendor_rust,
 )
 from .pkgmetadata.pep376 import verbatim_dist_name
 
@@ -335,12 +334,6 @@ def build_wheel(
         build_env=build_env,
     )
 
-    # Isolate Rust build artifacts per package to prevent CARGO_TARGET_DIR
-    # collisions during parallel builds and EXDEV (cross-device rename)
-    # failures.
-    if vendor_rust.has_rust_build_backend(req, sdist_root_dir):
-        extra_environ.setdefault("CARGO_TARGET_DIR", str(sdist_root_dir / "target"))
-
     if pbi.build_ext_parallel:
         logger.warning(
             "%s: build_ext_parallel is deprecated and will be removed in a "

tests/test_wheels.py

@@ -337,123 +337,3 @@ def test_validate_wheel_file(
     else:
         with pytest.raises(ValueError):
             wheels.validate_wheel_filename(req, version, wheel_file)
-
-
-@patch("fromager.wheels.add_extra_metadata_to_wheels")
-@patch("fromager.wheels.overrides.find_and_invoke")
-@patch("fromager.wheels.vendor_rust.has_rust_build_backend", return_value=True)
-@patch("fromager.wheels.packagesettings.get_extra_environ", return_value={})
-def test_build_wheel_sets_cargo_target_dir_for_rust_packages(
-    mock_get_extra_environ: Mock,
-    mock_has_rust: Mock,
-    mock_find_and_invoke: Mock,
-    mock_add_metadata: Mock,
-    tmp_path: pathlib.Path,
-    tmp_context: context.WorkContext,
-) -> None:
-    """CARGO_TARGET_DIR is set per package for Rust builds."""
-    req = Requirement("some-rust-pkg==1.0.0")
-    sdist_root = tmp_path / "some_rust_pkg-1.0.0"
-    sdist_root.mkdir()
-    build_env = build_environment.BuildEnvironment(
-        ctx=tmp_context,
-        req=req,
-        sdist_root_dir=sdist_root,
-    )
-
-    wheel_file = tmp_context.wheels_build / "some_rust_pkg-1.0.0-py3-none-any.whl"
-    wheel_file.parent.mkdir(parents=True, exist_ok=True)
-    wheel_file.touch()
-    mock_add_metadata.return_value = wheel_file
-
-    wheels.build_wheel(
-        ctx=tmp_context,
-        req=req,
-        sdist_root_dir=sdist_root,
-        version=Version("1.0.0"),
-        build_env=build_env,
-    )
-
-    extra_environ = mock_find_and_invoke.call_args.kwargs["extra_environ"]
-    assert extra_environ["CARGO_TARGET_DIR"] == str(sdist_root / "target")
-
-
-@patch("fromager.wheels.add_extra_metadata_to_wheels")
-@patch("fromager.wheels.overrides.find_and_invoke")
-@patch("fromager.wheels.vendor_rust.has_rust_build_backend", return_value=True)
-@patch(
-    "fromager.wheels.packagesettings.get_extra_environ",
-    return_value={"CARGO_TARGET_DIR": "/custom/target"},
-)
-def test_build_wheel_does_not_override_explicit_cargo_target_dir(
-    mock_get_extra_environ: Mock,
-    mock_has_rust: Mock,
-    mock_find_and_invoke: Mock,
-    mock_add_metadata: Mock,
-    tmp_path: pathlib.Path,
-    tmp_context: context.WorkContext,
-) -> None:
-    """Per-package CARGO_TARGET_DIR from settings takes precedence."""
-    req = Requirement("some-rust-pkg==1.0.0")
-    sdist_root = tmp_path / "some_rust_pkg-1.0.0"
-    sdist_root.mkdir()
-    build_env = build_environment.BuildEnvironment(
-        ctx=tmp_context,
-        req=req,
-        sdist_root_dir=sdist_root,
-    )
-
-    wheel_file = tmp_context.wheels_build / "some_rust_pkg-1.0.0-py3-none-any.whl"
-    wheel_file.parent.mkdir(parents=True, exist_ok=True)
-    wheel_file.touch()
-    mock_add_metadata.return_value = wheel_file
-
-    wheels.build_wheel(
-        ctx=tmp_context,
-        req=req,
-        sdist_root_dir=sdist_root,
-        version=Version("1.0.0"),
-        build_env=build_env,
-    )
-
-    extra_environ = mock_find_and_invoke.call_args.kwargs["extra_environ"]
-    assert extra_environ["CARGO_TARGET_DIR"] == "/custom/target"
-
-
-@patch("fromager.wheels.add_extra_metadata_to_wheels")
-@patch("fromager.wheels.overrides.find_and_invoke")
-@patch("fromager.wheels.vendor_rust.has_rust_build_backend", return_value=False)
-@patch("fromager.wheels.packagesettings.get_extra_environ", return_value={})
-def test_build_wheel_skips_cargo_target_dir_for_non_rust_packages(
-    mock_get_extra_environ: Mock,
-    mock_has_rust: Mock,
-    mock_find_and_invoke: Mock,
-    mock_add_metadata: Mock,
-    tmp_path: pathlib.Path,
-    tmp_context: context.WorkContext,
-) -> None:
-    """Non-Rust packages do not get CARGO_TARGET_DIR."""
-    req = Requirement("pure-python-pkg==1.0.0")
-    sdist_root = tmp_path / "pure_python_pkg-1.0.0"
-    sdist_root.mkdir()
-    build_env = build_environment.BuildEnvironment(
-        ctx=tmp_context,
-        req=req,
-        sdist_root_dir=sdist_root,
-    )
-
-    wheel_file = tmp_context.wheels_build / "pure_python_pkg-1.0.0-py3-none-any.whl"
-    wheel_file.parent.mkdir(parents=True, exist_ok=True)
-    wheel_file.touch()
-    mock_add_metadata.return_value = wheel_file
-
-    wheels.build_wheel(
-        ctx=tmp_context,
-        req=req,
-        sdist_root_dir=sdist_root,
-        version=Version("1.0.0"),
-        build_env=build_env,
-    )
-
-    extra_environ = mock_find_and_invoke.call_args.kwargs["extra_environ"]
-    assert "CARGO_TARGET_DIR" not in extra_environ