Fix platform config values for v1 recipes

conda_build/_rattler_build/compat.py

@@ -306,12 +306,6 @@ def run_rattler(command: str, parsed_args: argparse.Namespace, config: Config) -
     channels: list[str] = []
     extra_context: dict[str, str] = {}
     show_logs: bool = getattr(parsed_args, "quiet", False) is False
-    target_platform: str = config.variant.get("host_platform", config.subdir)
-    build_platform: str = config.variant.get("build_platform", config.subdir)
-    host_platform: str = config.variant.get("target_platform", config.subdir)
-    noarch_build_platform: str = config.variant.get(
-        "noarch_build_platform", config.subdir
-    )
     variant_config: VariantConfig = VariantConfig()
 
     # select list of channels to iterate over:
@@ -367,18 +361,27 @@ def run_rattler(command: str, parsed_args: argparse.Namespace, config: Config) -
             recipe_config_filenames=CONFIG_FILES,
         )
 
-    if command == "build":
-        if parsed_args.extra_meta:
-            extra_context.update(parsed_args.extra_meta)
-        if parsed_args.output_folder:
-            output_dir = parsed_args.output_folder
-        no_build_id = not parsed_args.set_build_id
-        skip_existing = parsed_args.skip_existing or "none"
-        no_include_recipe = not parsed_args.include_recipe
-        if parsed_args.conda_pkg_format == CondaPkgFormat.V2:
-            package_format = "conda"
-        else:
-            package_format = ".tar.bz2"
+    # configure variant
+    # merge config files in the order they are stacked
+    if config_files:
+        for variant in config_files:
+            variant_config = variant_config.merge(VariantConfig.from_file(variant))
+
+    def get_config_value(name):
+        value = variant_config.get(name, config.subdir)
+
+        if isinstance(value, list):
+            if len(value) != 1:
+                raise ValueError(
+                    f"Expected a single value for {name}, got {len(value)} values: {value}"
+                )
+            return value[0]
+        return value
+
+    build_platform = get_config_value("build_platform")
+    host_platform = get_config_value("host_platform")
+    target_platform = get_config_value("target_platform")
+    noarch_build_platform = get_config_value("noarch_build_platform")
 
     # common tool / platform / render configuration
     tool_config = ToolConfiguration(
@@ -400,19 +403,26 @@ def run_rattler(command: str, parsed_args: argparse.Namespace, config: Config) -
         extra_context=extra_context,
     )
 
+    if command == "build":
+        if parsed_args.extra_meta:
+            extra_context.update(parsed_args.extra_meta)
+        if parsed_args.output_folder:
+            output_dir = parsed_args.output_folder
+        no_build_id = not parsed_args.set_build_id
+        skip_existing = parsed_args.skip_existing or "none"
+        no_include_recipe = not parsed_args.include_recipe
+        if parsed_args.conda_pkg_format == CondaPkgFormat.V2:
+            package_format = "conda"
+        else:
+            package_format = ".tar.bz2"
+
     if command == "render":
         recipes = [str(Path(parsed_args.recipe) / "recipe.yaml")]
     else:
         recipes = [
             str(Path(recipe_dir) / "recipe.yaml") for recipe_dir in parsed_args.recipe
         ]
 
-    # configure variant
-    # merge config files in the order they are stacked
-    if config_files:
-        for variant in config_files:
-            variant_config = variant_config.merge(VariantConfig.from_file(variant))
-
     recipe_results: list[RecipeResult] = []
 
     for recipe_path in recipes:

news/6015-v1-recipe-platform-config.md

@@ -0,0 +1,19 @@
+### Enhancements
+
+* <news item>
+
+### Bug fixes
+
+* Fix platform config settings when building v1 recipes by checking `VariantConfig()` instead of `config.variant` (#6015).
+
+### Deprecations
+
+* <news item>
+
+### Docs
+
+* <news item>
+
+### Other
+
+* <news item>

tests/cli/test_main_build.py

@@ -7,7 +7,9 @@
 from pathlib import Path
 from typing import TYPE_CHECKING
 
+import conda_package_handling
 import pytest
+import yaml
 from conda.base.context import context
 from conda.exceptions import PackagesNotFoundError
 
@@ -593,6 +595,56 @@ def test_build_v1_recipe_multi_output(testing_workdir: str) -> None:
     assert len(conda_packages) == 2
 
 
+@pytest.mark.parametrize(
+    "target_platform, variant_name",
+    [
+        ("linux-aarch64", "cbc_aarch64.yml"),
+        ("osx-arm64", "cbc_osx_arm64.yml"),
+    ],
+    ids=["linux-aarch64", "osx-arm64"],
+)
+def test_v1_recipe_platform_config(
+    testing_workdir: str, target_platform: str, variant_name: str
+) -> None:
+    """Verify platform configuration settings in v1 recipes"""
+    recipe = os.path.join(metadata_dir, "..", "variants", "33_v1_recipe_multi_output")
+
+    out = Path(testing_workdir, "out")
+    out.mkdir(parents=True)
+
+    variant = os.path.join(recipe, "variants", variant_name)
+    args = [
+        recipe,
+        "-m",
+        variant,
+        "--output-folder",
+        str(out),
+    ]
+    main_build.execute(args)
+
+    conda_packages = sorted(out.rglob("*.conda"))
+
+    for pkg in conda_packages:
+        extract_dir = Path(testing_workdir, "extracted", pkg.stem)
+        extract_dir.mkdir(parents=True, exist_ok=True)
+
+        conda_package_handling.api.extract(str(pkg), dest_dir=str(extract_dir))
+
+        rendered_recipe = extract_dir / "info" / "recipe" / "rendered_recipe.yaml"
+
+        with rendered_recipe.open() as f:
+            recipe_data = yaml.safe_load(f)
+
+        # target_platform is in build_configuration.target_platform
+        build_config = recipe_data.get("build_configuration", {})
+        assert build_config, f"missing build_configuration in {pkg}"
+
+        assert build_config.get("target_platform") == target_platform, (
+            f"expected target_platform={target_platform} in build_configuration, "
+            f"got {build_config.get('target_platform')}"
+        )
+
+
 def test_build_v1_recipe_result_report(capsys) -> None:
     """Test for checking build summary report when building multiple recipes"""
     recipe1 = os.path.join(metadata_dir, "..", "variants", "32_v1_recipe")

tests/test-recipes/variants/33_v1_recipe_multi_output/variants/cbc_aarch64.yml

@@ -0,0 +1,2 @@
+target_platform:
+- linux-aarch64

tests/test-recipes/variants/33_v1_recipe_multi_output/variants/cbc_osx_arm64.yml

@@ -0,0 +1,2 @@
+target_platform:
+- osx-arm64