Use build to handle installing providers in make-variant

Since we are going to be removing provider installation code in favor
of doing it directly inside the package manager, modify `make-variant`
command implementation to use the code from `build` directly for that
purpose.

Author: mgorny

pyproject.toml

@@ -29,6 +29,7 @@ dynamic = ["version"]
 
 [project.optional-dependencies]
 cli = [
+    "build>=1.2.0,<1.3",
     "tomlkit>=0.13,<0.14",
     "tzlocal>=3.0,<6",
 ]
@@ -41,6 +42,7 @@ dev = [
     "ruff>=0.10,<1.0",
 ]
 test = [
+    "build>=1.2.0,<1.3",
     "deepdiff>=8.0,<9.0",
     "hypothesis>=6.0.0,<7",
     "parameterized>=0.9.0,<0.10",

tests/commands/test_make_variant.py

@@ -11,6 +11,8 @@
 if TYPE_CHECKING:
     from pathlib import Path
 
+    from pytest_mock import MockerFixture
+
 
 @pytest.fixture
 def non_variant_wheel(test_artifact_path: Path) -> Path:
@@ -20,6 +22,16 @@ def non_variant_wheel(test_artifact_path: Path) -> Path:
     return whl_f
 
 
+@pytest.fixture
+def mocked_plugin_reqs(
+    mocker: MockerFixture,
+    test_plugin_package_req: str,
+) -> None:
+    mocker.patch(
+        "variantlib.models.variant_info.VariantInfo.get_provider_requires"
+    ).return_value = [test_plugin_package_req]
+
+
 @pytest.mark.parametrize(
     ("vhash", "properties"),
     [
@@ -51,6 +63,7 @@ def test_make_variant(
     non_variant_wheel: Path,
     test_artifact_path: Path,
     tmp_path: Path,
+    mocked_plugin_reqs: None,
 ) -> None:
     cmd_args = [
         "make-variant",
@@ -69,12 +82,7 @@ def test_make_variant(
             itertools.chain.from_iterable(["-p", vprop] for vprop in properties)
         )
 
-    if properties is not None:
-        with pytest.raises(RuntimeError, match="No module named 'test_plugin_package'"):
-            # This should fail because the plugin is not installed
-            main(cmd_args)
-
-    main([*cmd_args, "--skip-plugin-validation"])
+    main([*cmd_args])
 
     target_variant_wheel = (
         non_variant_wheel.parent / f"test_package-0-py3-none-any-{vhash}.whl"

variantlib/commands/make_variant.py

@@ -6,7 +6,9 @@
 import logging
 import pathlib
 import shutil
+import sys
 import zipfile
+from subprocess import CalledProcessError
 
 from variantlib import __package_name__
 from variantlib.api import VariantDescription
@@ -129,24 +131,45 @@ def _make_variant(
         vdesc = VariantDescription(properties=properties)
 
         if validate_properties:
-            # Verify whether the variant properties are valid
-            vdesc_valid = validate_variant(vdesc, variant_info=variant_info)
-            if vdesc_valid.invalid_properties:
-                invalid_str = ", ".join(
-                    x.to_str() for x in vdesc_valid.invalid_properties
-                )
-                raise ValidationError(
-                    "The following variant properties are invalid according to the "
-                    f"plugins: {invalid_str}"
-                )
-            if vdesc_valid.unknown_properties:
-                unknown_str = ", ".join(
-                    x.to_str() for x in vdesc_valid.unknown_properties
-                )
-                raise ValidationError(
-                    "The following variant properties use namespaces that are not "
-                    f"provided by any installed plugin: {unknown_str}"
+            from build.env import DefaultIsolatedEnv
+
+            with DefaultIsolatedEnv() as venv:
+                try:
+                    venv.install(
+                        variant_info.get_provider_requires(
+                            {vprop.namespace for vprop in vdesc.properties}
+                        )
+                    )
+                except CalledProcessError as err:
+                    sys.stderr.write(
+                        "Installing variant provider dependencies failed:\n"
+                        f"{err.stderr.decode()}"
+                    )
+                    raise
+
+                # Verify whether the variant properties are valid
+                vdesc_valid = validate_variant(
+                    vdesc,
+                    variant_info=variant_info,
+                    use_auto_install=False,
+                    venv_path=venv.path,
                 )
+                if vdesc_valid.invalid_properties:
+                    invalid_str = ", ".join(
+                        x.to_str() for x in vdesc_valid.invalid_properties
+                    )
+                    raise ValidationError(
+                        "The following variant properties are invalid according to the "
+                        f"plugins: {invalid_str}"
+                    )
+                if vdesc_valid.unknown_properties:
+                    unknown_str = ", ".join(
+                        x.to_str() for x in vdesc_valid.unknown_properties
+                    )
+                    raise ValidationError(
+                        "The following variant properties use namespaces that are not "
+                        f"provided by any installed plugin: {unknown_str}"
+                    )
     else:
         # Create a null variant
         vdesc = VariantDescription()