Workaround oracle/graalpython#491 also when uv is not available

Author: timfel

cibuildwheel/platforms/windows.py

@@ -418,18 +418,6 @@ def build(options: Options, tmp_path: Path) -> None:
             build_options = options.build_options(config.identifier)
             build_frontend = build_options.build_frontend or BuildFrontendConfig("build")
 
-            if (
-                config.identifier.startswith("gp")
-                and build_frontend.name == "build"
-                and "--no-isolation" not in build_frontend.args
-                and "-n" not in build_frontend.args
-            ):
-                # GraalPy fails to discover its standard library when a venv is created
-                # from a virtualenv seeded executable. See
-                # https://github.com/oracle/graalpython/issues/491 and remove this once
-                # fixed upstream.
-                build_frontend = BuildFrontendConfig("build[uv]", build_frontend.args)
-
             use_uv = build_frontend.name == "build[uv]" and can_use_uv(config)
             log.build_start(config.identifier)
 
@@ -482,6 +470,22 @@ def build(options: Options, tmp_path: Path) -> None:
                     build_frontend, build_options.build_verbosity, build_options.config_settings
                 )
 
+                if (
+                    config.identifier.startswith("gp")
+                    and build_frontend.name == "build"
+                    and "--no-isolation" not in extra_flags
+                    and "-n" not in extra_flags
+                ):
+                    # GraalPy fails to discover its standard library when a venv is created
+                    # from a virtualenv seeded executable. See
+                    # https://github.com/oracle/graalpython/issues/491 and remove this once
+                    # fixed upstream.
+                    log.notice(
+                        "Disabling build isolation to workaround GraalPy bug. If the build fails, consider using pip or build[uv] as build frontend."
+                    )
+                    shell("graalpy -m pip install setuptools wheel", env=env)
+                    extra_flags = [*extra_flags, "-n"]
+
                 build_env = env.copy()
                 if not use_uv:
                     build_env["VIRTUALENV_PIP"] = pip_version

test/test_pep518.py

@@ -33,11 +33,32 @@ def test_pep518(tmp_path, build_frontend_env):
     project_dir = tmp_path / "project"
     basic_project.generate(project_dir)
 
+    # GraalPy fails to discover its standard library when a venv is created
+    # from a virtualenv seeded executable. See
+    # https://github.com/oracle/graalpython/issues/491 and remove this once
+    # fixed upstream.
+    if (
+        build_frontend_env["CIBW_BUILD_FRONTEND"] == "build"
+        and utils.platform == "windows"
+    ):
+        build_frontend_env["CIBW_SKIP"] = "gp*"
+
     # build the wheels
     actual_wheels = utils.cibuildwheel_run(project_dir, add_env=build_frontend_env)
 
     # check that the expected wheels are produced
     expected_wheels = utils.expected_wheels("spam", "0.1.0")
+
+    # GraalPy fails to discover its standard library when a venv is created
+    # from a virtualenv seeded executable. See
+    # https://github.com/oracle/graalpython/issues/491 and remove this once
+    # fixed upstream.
+    if (
+        build_frontend_env["CIBW_BUILD_FRONTEND"] == "build"
+        and utils.platform == "windows"
+    ):
+        expected_wheels = [w for w in expected_wheels if "graalpy" not in w]
+
     assert set(actual_wheels) == set(expected_wheels)
 
     # These checks ensure an extra file is not created when using custom