fix: use python_min in skip conditions for noarch Python recipes

conda_recipe_manager/parser/recipe_parser_convert.py

@@ -308,6 +308,17 @@ def _upgrade_ambiguous_deps(self) -> None:
                 )
                 self._msg_tbl.add_message(MessageCategory.WARNING, f"Version on dependency changed to: {spec_str}")
 
+    def _is_noarch_python(self, base_path: str = "/") -> bool:
+        """
+        Checks if the recipe (or a specific output) has `noarch: python` set.
+
+        :param base_path: Base path to check (defaults to root for single-output recipes)
+        :returns: True if the recipe has `noarch: python` set, False otherwise.
+        """
+        noarch_path = RecipeParser.append_to_path(base_path, "/build/noarch")
+        noarch_value = self._v1_recipe.get_value(noarch_path, default=None)
+        return noarch_value == "python"
+
     def _upgrade_selectors_to_conditionals(self) -> None:
         """
         Upgrades the proprietary comment-based selector syntax to equivalent conditional logic statements.
@@ -317,6 +328,12 @@ def _upgrade_selectors_to_conditionals(self) -> None:
         conda docs for common selectors:
           https://docs.conda.io/projects/conda-build/en/latest/resources/define-metadata.html#preprocessing-selectors
         """
+        # Per CFEP-25, noarch Python recipes should use `python_min` instead of `python` in match expressions,
+        # as only `python_min` is defined in the variant configuration for noarch packages.
+        # See: https://github.com/conda/conda-recipe-manager/issues/479
+        is_noarch_python: Final[bool] = self._is_noarch_python()
+        python_match_var: Final[str] = "python_min" if is_noarch_python else "python"
+
         selector_path_map: dict[str, str] = {}
         for selector, instances in self._v1_recipe._selector_tbl.items():  # pylint: disable=protected-access
             for info in instances:
@@ -333,21 +350,21 @@ def _upgrade_selectors_to_conditionals(self) -> None:
                 # Some commonly used selectors (like `py<36`) need to be upgraded. Otherwise, these expressions will be
                 # interpreted as strings. See this CEP PR for more details: https://github.com/conda/ceps/pull/71
                 bool_expression = Regex.SELECTOR_PYTHON_VERSION_REPLACEMENT.sub(
-                    r'match(python, "\1\2.\3")', bool_expression
+                    rf'match({python_match_var}, "\1\2.\3")', bool_expression
                 )
                 # Upgrades for less common `py36` and `not py27` selectors
                 bool_expression = Regex.SELECTOR_PYTHON_VERSION_EQ_REPLACEMENT.sub(
-                    r'match(python, "==\1.\2")', bool_expression
+                    rf'match({python_match_var}, "==\1.\2")', bool_expression
                 )
                 bool_expression = Regex.SELECTOR_PYTHON_VERSION_NE_REPLACEMENT.sub(
-                    r'match(python, "!=\1.\2")', bool_expression
+                    rf'match({python_match_var}, "!=\1.\2")', bool_expression
                 )
                 # Upgrades for less common `py2k` and `py3k` selectors
                 bool_expression = Regex.SELECTOR_PYTHON_VERSION_PY2K_REPLACEMENT.sub(
-                    r'match(python, ">=2,<3")', bool_expression
+                    rf'match({python_match_var}, ">=2,<3")', bool_expression
                 )
                 bool_expression = Regex.SELECTOR_PYTHON_VERSION_PY3K_REPLACEMENT.sub(
-                    r'match(python, ">=3,<4")', bool_expression
+                    rf'match({python_match_var}, ">=3,<4")', bool_expression
                 )
 
                 # TODO other common selectors to support:

tests/parser/test_recipe_parser_convert.py

@@ -314,6 +314,12 @@ def test_pre_process_recipe_text(input_file: str, expected_file: str) -> None:
             [],
             [],
         ),
+        # Issue #479: noarch python recipes should use `python_min` instead of `python` in skip conditions
+        (
+            "noarch-python-skip.yaml",
+            [],
+            [],
+        ),
     ],
 )
 def test_render_to_v1_recipe_format(file: str, errors: list[str], warnings: list[str]) -> None:

tests/test_aux_files/noarch-python-skip.yaml

@@ -0,0 +1,37 @@
+{% set name = "noarch-python-skip" %}
+{% set version = "1.0.0" %}
+
+package:
+  name: {{ name|lower }}
+  version: {{ version }}
+
+source:
+  url: https://pypi.io/packages/source/{{ name[0] }}/{{ name }}/{{ name }}-{{ version }}.tar.gz
+  sha256: 6d3ac79e36c9ee593c5d4fb33a50cca0e3adceb6ef5cff8b8e5aef67b4c4aaf2
+
+build:
+  number: 0
+  noarch: python
+  skip: true  # [py<310]
+  script: {{ PYTHON }} -m pip install . -vv --no-deps --no-build-isolation
+
+requirements:
+  host:
+    - python >=3.10
+    - pip
+  run:
+    - python >=3.10
+
+test:
+  imports:
+    - noarch_python_skip
+  commands:
+    - pip check
+  requires:
+    - pip
+
+about:
+  home: https://github.com/example/noarch-python-skip
+  summary: Test package for noarch python skip condition conversion
+  license: MIT
+  license_file: LICENSE

tests/test_aux_files/v1_format/v1_noarch-python-skip.yaml

@@ -0,0 +1,38 @@
+schema_version: 1
+
+context:
+  name: noarch-python-skip
+  version: 1.0.0
+
+package:
+  name: ${{ name|lower }}
+  version: ${{ version }}
+
+source:
+  url: https://pypi.io/packages/source/${{ name[0] }}/${{ name }}/${{ name }}-${{ version }}.tar.gz
+  sha256: 6d3ac79e36c9ee593c5d4fb33a50cca0e3adceb6ef5cff8b8e5aef67b4c4aaf2
+
+build:
+  number: 0
+  skip: match(python_min, "<3.10")
+  noarch: python
+  script: ${{ PYTHON }} -m pip install . -vv --no-deps --no-build-isolation
+
+requirements:
+  host:
+    - python >=3.10
+    - pip
+  run:
+    - python >=3.10
+
+tests:
+  - python:
+      imports:
+        - noarch_python_skip
+      pip_check: true
+
+about:
+  summary: Test package for noarch python skip condition conversion
+  license: MIT
+  license_file: LICENSE
+  homepage: https://github.com/example/noarch-python-skip