Ensure get_requires* hook is called before prepare_metadata*

docs/changelog/3043.bugfix.rst

@@ -0,0 +1 @@
+Ensure that ``get_requires*`` build hooks are called before ``prepare_metadata*``

src/tox/tox_env/python/virtual_env/package/pyproject.py

@@ -5,6 +5,7 @@
 import sys
 from collections import defaultdict
 from contextlib import contextmanager
+from itertools import chain
 from pathlib import Path
 from threading import RLock
 from typing import TYPE_CHECKING, Any, Dict, Generator, Iterator, NoReturn, Optional, Sequence, cast
@@ -103,6 +104,7 @@ def __init__(self, create_args: ToxEnvCreateArgs) -> None:
         self._pkg_lock = RLock()  # can build only one package at a time
         self.root = self.conf["package_root"]
         self._package_paths: set[Path] = set()
+        self._installed_build_requirements: set[Requirement] = set()
 
     @staticmethod
     def id() -> str:  # noqa: A003
@@ -157,14 +159,19 @@ def _setup_env(self) -> None:
         if "editable" in self.builds:
             if not self._frontend.optional_hooks["build_editable"]:
                 raise BuildEditableNotSupportedError
-            build_requires = self._frontend.get_requires_for_build_editable().requires
-            self._install(build_requires, PythonPackageToxEnv.__name__, "requires_for_build_editable")
+            self._setup_build_requires("editable")
         if "wheel" in self.builds:
-            build_requires = self._frontend.get_requires_for_build_wheel().requires
-            self._install(build_requires, PythonPackageToxEnv.__name__, "requires_for_build_wheel")
+            self._setup_build_requires("wheel")
         if "sdist" in self.builds or "external" in self.builds:
-            build_requires = self._frontend.get_requires_for_build_sdist().requires
-            self._install(build_requires, PythonPackageToxEnv.__name__, "requires_for_build_sdist")
+            self._setup_build_requires("sdist")
+
+    def _setup_build_requires(self, of_type: str) -> None:
+        hook = getattr(self._frontend, f"get_requires_for_build_{of_type}")
+        build_requires = hook().requires  # already cached via Pep517VirtualEnvFrontend
+        pending = [req for req in build_requires if req not in self._installed_build_requirements]
+        if pending:
+            self._install(pending, PythonPackageToxEnv.__name__, f"requires_for_build_{of_type}")
+            self._installed_build_requirements.update(pending)
 
     def _teardown(self) -> None:
         executor = self._frontend.backend_executor
@@ -312,8 +319,10 @@ def _ensure_meta_present(self, for_env: EnvConfigSet) -> None:
         self.setup()
         end = self._frontend
         if for_env["package"] == "editable":
+            self._setup_build_requires("editable")
             dist_info = end.prepare_metadata_for_build_editable(self.meta_folder, self._wheel_config_settings).metadata
         else:
+            self._setup_build_requires("wheel")
             dist_info = end.prepare_metadata_for_build_wheel(self.meta_folder, self._wheel_config_settings).metadata
         self._distribution_meta = Distribution.at(str(dist_info))
 
@@ -332,12 +341,19 @@ def __init__(self, root: Path, env: Pep517VirtualEnvPackager) -> None:
         self._backend_executor_: LocalSubProcessPep517Executor | None = None
         into: dict[str, Any] = {}
 
-        for build_type in ("editable", "sdist", "wheel"):  # wrap build methods in a cache wrapper
+        build_types = ["editable", "sdist", "wheel"]
+        for hook in chain(
+            (f"build_{build_type}" for build_type in build_types),
+            (f"get_requires_for_build_{build_type}" for build_type in build_types),
+            (f"prepare_metadata_for_build_{build_type}" for build_type in build_types),
+        ):  # wrap build methods in a cache wrapper
+            if not hasattr(self, hook):
+                continue
 
-            def key(*args: Any, bound_return: str = build_type, **kwargs: Any) -> str:  # noqa: ARG001
+            def key(*args: Any, bound_return: str = hook, **kwargs: Any) -> str:  # noqa: ARG001
                 return bound_return
 
-            setattr(self, f"build_{build_type}", cached(into, key=key)(getattr(self, f"build_{build_type}")))
+            setattr(self, hook, cached(into, key=key)(getattr(self, hook)))
 
     @property
     def backend_cmd(self) -> Sequence[str]:

tests/tox_env/python/virtual_env/package/test_package_cmd_builder.py

@@ -56,6 +56,8 @@ def test_tox_install_pkg_sdist(tox_project: ToxProjectCreator, pkg_with_extras_p
         (".pkg_external_sdist_meta", "install_requires", ["setuptools", "wheel"]),
         (".pkg_external_sdist_meta", "_optional_hooks", []),
         (".pkg_external_sdist_meta", "get_requires_for_build_sdist", []),
+        (".pkg_external_sdist_meta", "get_requires_for_build_wheel", []),  # required before prepare_metadata*
+        (".pkg_external_sdist_meta", "install_requires_for_build_wheel", ["wheel"]),
         (".pkg_external_sdist_meta", "prepare_metadata_for_build_wheel", []),
         ("py", "install_package_deps", deps),
         ("py", "install_package", ["--force-reinstall", "--no-deps", str(pkg_with_extras_project_sdist)]),

tests/tox_env/python/virtual_env/package/test_package_pyproject.py

@@ -213,6 +213,7 @@ def test_pyproject_deps_static_with_dynamic(  # noqa: PLR0913
     expected_calls = [
         (".pkg", "_optional_hooks"),
         (".pkg", "get_requires_for_build_sdist"),
+        (".pkg", "get_requires_for_build_wheel"),
         (".pkg", "build_wheel"),
         (".pkg", "build_sdist"),
         ("py", "install_package_deps"),
@@ -239,10 +240,10 @@ def test_pyproject_no_build_editable_fallback(tox_project: ToxProjectCreator, de
 
     expected_calls = [
         (".pkg", "_optional_hooks"),
+        (".pkg", "get_requires_for_build_wheel"),
         (".pkg", "build_wheel"),
         (".pkg", "get_requires_for_build_sdist"),
         ("a", "install_package"),
-        (".pkg", "get_requires_for_build_sdist"),
         ("b", "install_package"),
         (".pkg", "_exit"),
     ]

tests/tox_env/test_tox_env_runner.py

@@ -24,6 +24,7 @@ def test_package_only(
     expected_calls = [
         (".pkg", "_optional_hooks"),
         (".pkg", "get_requires_for_build_sdist"),
+        (".pkg", "get_requires_for_build_wheel"),
         (".pkg", "build_wheel"),
         (".pkg", "build_sdist"),
         (".pkg", "_exit"),