test(e2e): port rules_pycross sdist-build cases

e2e/cases/MODULE.bazel

@@ -104,6 +104,10 @@ include("//multi-project-hub:setup.MODULE.bazel")
 include("//oci:setup.MODULE.bazel")
 include("//pbs-cc-toolchain:setup.MODULE.bazel")
 include("//pth-namespace-547:setup.MODULE.bazel")
+include("//pycross-distutils-probe:setup.MODULE.bazel")
+include("//pycross-patches:setup.MODULE.bazel")
+include("//pycross-pure-python:setup.MODULE.bazel")
+include("//pycross-setuptools:setup.MODULE.bazel")
 include("//pytest-anyio-plugin:setup.MODULE.bazel")
 include("//pytest-main-867:setup.MODULE.bazel")
 include("//pytest-mock-530:setup.MODULE.bazel")

e2e/cases/pycross-distutils-probe/BUILD.bazel

@@ -0,0 +1,18 @@
+# Ported from rules_pycross tests/e2e/build_setuptools's distutils probe.
+# See __test__.py for what the probe asserts.
+
+load("@aspect_rules_py//py:defs.bzl", "py_test")
+
+py_test(
+    name = "test",
+    srcs = ["__test__.py"],
+    data = ["@aspect_rules_py//uv/private/pep517_whl:build_helper.py"],
+    dep_group = "pycross_distutils_probe",
+    main = "__test__.py",
+    python_version = "3.12",
+    deps = [
+        "@pypi_pycross_distutils_probe//build",
+        "@pypi_pycross_distutils_probe//setuptools",
+        "@pypi_pycross_distutils_probe//wheel",
+    ],
+)

e2e/cases/pycross-distutils-probe/__test__.py

@@ -0,0 +1,108 @@
+"""Drive build_helper.py against rules_pycross's distutils probe sdist.
+
+Ported from rules_pycross tests/e2e/build_setuptools (`distutils_probe/`,
+`build_distutils_probe_sdist.py`, `test_distutils_probe.py`). The sdist's
+`build_py` command shells out to a *fresh* interpreter and imports
+`distutils.util`; on Python 3.12+ that only resolves when setuptools'
+`_distutils_hack` is reachable from the child. A build action that leaks a
+stale `PYTHONPATH`/`PYTHONHOME` — exactly what rule.bzl's
+`_INHERITED_PYTHON_ENV` filter strips — poisons the child while the parent
+backend keeps working, so the failure is invisible to a plain "does it
+build" check.
+
+Structured like `uv-sdist-mpicc`: the sdist is assembled in-process and
+build_helper.py runs as a subprocess with a minimal env (bare PATH, no
+PYTHON* variables), so nothing is fetched from the network and nothing
+leaks in from the test's own environment.
+"""
+
+import os
+import subprocess
+import sys
+import tarfile
+import tempfile
+import textwrap
+
+PYPROJECT = textwrap.dedent(
+    """\
+    [build-system]
+    requires = ["setuptools", "wheel"]
+    build-backend = "setuptools.build_meta"
+    """
+)
+
+SETUP_PY = textwrap.dedent(
+    """\
+    import subprocess
+    import sys
+
+    from setuptools import setup
+    from setuptools.command.build_py import build_py as _build_py
+
+
+    class build_py(_build_py):
+        def run(self):
+            subprocess.check_call([sys.executable, "-c", "from distutils.util import byte_compile"])
+            super().run()
+
+
+    setup(
+        name="distutils_probe",
+        version="0.1",
+        packages=["distutils_probe_pkg"],
+        cmdclass={"build_py": build_py},
+    )
+    """
+)
+
+
+def find_build_helper() -> str:
+    srcdir = os.environ["TEST_SRCDIR"]
+    for root, _, files in os.walk(srcdir, followlinks=True):
+        if "build_helper.py" in files and root.endswith(os.path.join("uv", "private", "pep517_whl")):
+            return os.path.join(root, "build_helper.py")
+    raise AssertionError("build_helper.py not found under TEST_SRCDIR")
+
+
+def make_sdist(workdir: str) -> str:
+    pkgdir = os.path.join(workdir, "distutils_probe-0.1")
+    os.makedirs(os.path.join(pkgdir, "distutils_probe_pkg"))
+    with open(os.path.join(pkgdir, "pyproject.toml"), "w") as f:
+        f.write(PYPROJECT)
+    with open(os.path.join(pkgdir, "setup.py"), "w") as f:
+        f.write(SETUP_PY)
+    with open(os.path.join(pkgdir, "distutils_probe_pkg", "__init__.py"), "w") as f:
+        f.write("")
+    sdist = os.path.join(workdir, "distutils_probe-0.1.tar.gz")
+    with tarfile.open(sdist, "w:gz") as tar:
+        tar.add(pkgdir, arcname="distutils_probe-0.1")
+    return sdist
+
+
+def main() -> None:
+    helper = find_build_helper()
+    tmp = tempfile.mkdtemp(dir=os.environ.get("TEST_TMPDIR"))
+    sdist = make_sdist(tmp)
+    outdir = os.path.join(tmp, "out")
+
+    result = subprocess.run(
+        [sys.executable, helper, "--validate-anyarch", sdist, outdir],
+        capture_output=True,
+        text=True,
+        env={
+            "PATH": os.pathsep.join(["/usr/bin", "/bin"]),
+            "HOME": os.environ.get("TEST_TMPDIR", "/tmp"),
+        },
+    )
+    if result.returncode != 0:
+        raise AssertionError(
+            "build_helper failed:\nstdout:\n{}\nstderr:\n{}".format(result.stdout, result.stderr)
+        )
+
+    wheels = [f for f in os.listdir(outdir) if f.endswith(".whl")]
+    assert wheels, "no wheel produced"
+    print("OK: {}".format(wheels))
+
+
+if __name__ == "__main__":
+    main()

e2e/cases/pycross-distutils-probe/pyproject.toml

@@ -0,0 +1,9 @@
+[project]
+name = "pycross_distutils_probe"
+version = "0.0.0"
+requires-python = ">=3.11"
+dependencies = [
+    "build",
+    "setuptools",
+    "wheel",
+]

e2e/cases/pycross-distutils-probe/setup.MODULE.bazel

@@ -0,0 +1,22 @@
+"""Port of rules_pycross's `tests/e2e/build_setuptools` distutils probe.
+
+rules_pycross ships a synthetic sdist whose `build_py` command shells out to a
+fresh interpreter and imports `distutils.util`, guarding against a build
+environment that leaves the backend's child processes unable to find distutils
+(`SETUPTOOLS_USE_DISTUTILS`, a stale `PYTHONPATH`, or a stripped `PATH`).
+rule.bzl filters `PYTHONHOME`/`PYTHONPATH`/`PYTHONPLATLIBDIR` out of the
+action env for exactly this reason, so the probe is worth keeping.
+
+Driven the same way as `uv-sdist-mpicc`: the test invokes build_helper.py
+directly against a sdist it builds in-process, so no lockfile entry or
+network fetch is involved.
+"""
+
+uv = use_extension("@aspect_rules_py//uv:extensions.bzl", "uv")
+uv.declare_hub(hub_name = "pypi_pycross_distutils_probe")
+uv.project(
+    hub_name = "pypi_pycross_distutils_probe",
+    lock = "//pycross-distutils-probe:uv.lock",
+    pyproject = "//pycross-distutils-probe:pyproject.toml",
+)
+use_repo(uv, "pypi_pycross_distutils_probe")

e2e/cases/pycross-patches/BUILD.bazel

@@ -0,0 +1,22 @@
+# Ported from rules_pycross tests/e2e/patches_and_hooks.
+#
+# `PATCHED` comes from the pre-build patch (applied to the sdist source tree
+# before the PEP 517 backend runs), `POST_PATCHED` from the post-install patch
+# (applied to the unpacked wheel). The post-install hunk's context includes the
+# pre-build hunk's line, so the two must apply in that order.
+
+load("@aspect_rules_py//py:defs.bzl", "py_test")
+
+exports_files([
+    "patches/setproctitle-prebuild.patch",
+    "patches/setproctitle-postinstall.patch",
+])
+
+py_test(
+    name = "test_setproctitle_patched",
+    srcs = ["test_setproctitle_patched.py"],
+    dep_group = "pycross_patches",
+    main = "test_setproctitle_patched.py",
+    python_version = "3.12",
+    deps = ["@pypi_pycross_patches//setproctitle"],
+)

e2e/cases/pycross-patches/patches/setproctitle-postinstall.patch

@@ -0,0 +1,7 @@
+--- a/lib/python3.12/site-packages/setproctitle/__init__.py
++++ b/lib/python3.12/site-packages/setproctitle/__init__.py
+@@ -56,3 +56,4 @@
+ if sys.platform == "darwin":
+     getproctitle()
+ PATCHED = True
++POST_PATCHED = True

e2e/cases/pycross-patches/patches/setproctitle-prebuild.patch

@@ -0,0 +1,7 @@
+--- a/pkg/setproctitle/__init__.py	2026-06-04 13:22:25.044466888 +0000
++++ b/pkg/setproctitle/__init__.py	2026-06-04 13:23:03.082422796 +0000
+@@ -55,3 +55,4 @@
+ # by fork() on macOS (see #113).
+ if sys.platform == "darwin":
+     getproctitle()
++PATCHED = True

e2e/cases/pycross-patches/pyproject.toml

@@ -0,0 +1,13 @@
+[project]
+name = "pycross_patches"
+version = "0.0.0"
+requires-python = ">=3.11"
+dependencies = [
+    "build",
+    "setuptools",
+    "wheel",
+    "setproctitle==1.3.2",
+]
+
+[tool.uv]
+no-binary-package = ["setproctitle"]

e2e/cases/pycross-patches/setup.MODULE.bazel

@@ -0,0 +1,46 @@
+"""Port of rules_pycross's `tests/e2e/patches_and_hooks` workspace.
+
+setproctitle is forced to build from its sdist with both patch phases applied:
+a pre-build patch that lands in the source tree before the PEP 517 backend
+runs, and a post-install patch that rewrites the already-unpacked wheel. The
+two patches stack — the post-install hunk carries the pre-build patch's
+`PATCHED = True` line as context, so it only applies when the phases ran in
+order and an ordering regression fails the build itself, not just the
+runtime test.
+
+The post-install patch is written against the installed venv layout
+(`lib/python<X.Y>/site-packages/...`): rules_py applies post-install patches
+with `patch -d` rooted at the install tree, unlike rules_pycross's
+wheel-relative paths.
+
+Uses its own hub: the patched setproctitle must not be shared with
+`pycross-setuptools`, which builds the same version unpatched.
+
+Not ported: rules_pycross's `pre_build_hooks` / `post_build_hooks` /
+`path_tools` / `site_hooks` and its `repair_wheel` hook have no rules_py
+equivalent. `uv.override_package(toolchains = ..., env = ...)` covers the
+"inject something into the build environment" case those hooks serve; see
+`uv-sdist-jdk-build`.
+"""
+
+uv = use_extension("@aspect_rules_py//uv:extensions.bzl", "uv")
+uv.declare_hub(hub_name = "pypi_pycross_patches")
+uv.project(
+    default_build_dependencies = [
+        "build",
+        "setuptools",
+        "wheel",
+    ],
+    hub_name = "pypi_pycross_patches",
+    lock = "//pycross-patches:uv.lock",
+    pyproject = "//pycross-patches:pyproject.toml",
+)
+uv.override_package(
+    name = "setproctitle",
+    lock = "//pycross-patches:uv.lock",
+    post_install_patch_strip = 1,
+    post_install_patches = ["//pycross-patches:patches/setproctitle-postinstall.patch"],
+    pre_build_patch_strip = 1,
+    pre_build_patches = ["//pycross-patches:patches/setproctitle-prebuild.patch"],
+)
+use_repo(uv, "pypi_pycross_patches")

e2e/cases/pycross-patches/test_setproctitle_patched.py

@@ -0,0 +1,23 @@
+"""Assert both patch phases reached the installed setproctitle.
+
+Ported from rules_pycross tests/e2e/patches_and_hooks/tests/test_setproctitle.py.
+`PATCHED` comes from the pre-build patch, `POST_PATCHED` from the post-install
+patch. The upstream `SITE_HOOK_RAN` assertion is dropped: rules_py has no
+`site_hooks` equivalent.
+"""
+
+import unittest
+
+import setproctitle
+
+
+class TestSetproctitle(unittest.TestCase):
+    def test_import(self) -> None:
+        title = setproctitle.getproctitle()
+        self.assertIsNotNone(title)
+        self.assertTrue(setproctitle.PATCHED)
+        self.assertTrue(setproctitle.POST_PATCHED)
+
+
+if __name__ == "__main__":
+    unittest.main()