Support skipping pip_no_build_backend hints

Support skipping the hints about missing build backend dependency,
e.g. when the package itself is providing the build backend
(e.g. in poetry-core-feedstock).

Also requested in issue conda-forge#2170.

conda_smithy/data/conda-forge.json

@@ -818,6 +818,7 @@
     "Lints": {
       "enum": [
         "lint_noarch_selectors",
+        "hint_pip_no_build_backend",
         "hint_python_min"
       ],
       "title": "Lints",

conda_smithy/lint_recipe.py

@@ -593,26 +593,27 @@ def run_conda_forge_specific(
             )
 
     # 8: Ensure the recipe specifies a Python build backend if needed
-    host_or_build_reqs = (requirements_section.get("host") or []) or (
-        requirements_section.get("build") or []
-    )
-    hint_pip_no_build_backend(host_or_build_reqs, recipe_name, hints)
-    for out in outputs_section:
-        if recipe_version == 1:
-            output_requirements = rattler_loader.load_all_requirements(out)
-            build_reqs = output_requirements.get("build") or []
-            host_reqs = output_requirements.get("host") or []
-        else:
-            _req = out.get("requirements") or {}
-            if isinstance(_req, Mapping):
-                build_reqs = _req.get("build") or []
-                host_reqs = _req.get("host") or []
+    if "hint_pip_no_build_backend" not in lints_to_skip:
+        host_or_build_reqs = (requirements_section.get("host") or []) or (
+            requirements_section.get("build") or []
+        )
+        hint_pip_no_build_backend(host_or_build_reqs, recipe_name, hints)
+        for out in outputs_section:
+            if recipe_version == 1:
+                output_requirements = rattler_loader.load_all_requirements(out)
+                build_reqs = output_requirements.get("build") or []
+                host_reqs = output_requirements.get("host") or []
             else:
-                build_reqs = []
-                host_reqs = []
-
-        name = out.get("name", "").strip()
-        hint_pip_no_build_backend(host_reqs or build_reqs, name, hints)
+                _req = out.get("requirements") or {}
+                if isinstance(_req, Mapping):
+                    build_reqs = _req.get("build") or []
+                    host_reqs = _req.get("host") or []
+                else:
+                    build_reqs = []
+                    host_reqs = []
+
+            name = out.get("name", "").strip()
+            hint_pip_no_build_backend(host_reqs or build_reqs, name, hints)
 
     # 9: No duplicates in conda-forge.yml
     if (

conda_smithy/schema.py

@@ -96,6 +96,7 @@ class BotConfigVersionUpdatesSourcesChoice(StrEnum):
 
 class Lints(StrEnum):
     LINT_NOARCH_SELECTORS = "lint_noarch_selectors"
+    HINT_PIP_NO_BUILD_BACKEND = "hint_pip_no_build_backend"
     HINT_PYTHON_MIN = "hint_python_min"
 
 

tests/test_lint_recipe.py

@@ -3055,14 +3055,31 @@ def test_v1_package_name_version():
         ),
     ],
 )
+@pytest.mark.parametrize("skip", [False, True])
 def test_hint_pip_no_build_backend(
     meta_str,
     expected_hints,
     backend,
     outputs_to_add,
     outputs_expected_hints,
     remove_top_level,
+    skip,
+    tmp_path,
 ):
+    if skip:
+        if (
+            not expected_hints or remove_top_level
+        ) and not outputs_expected_hints:
+            pytest.skip("No hints expected")
+        with open(tmp_path / "conda-forge.yml", "w") as fh:
+            fh.write(
+                """
+linter:
+  skip:
+    - hint_pip_no_build_backend
+"""
+            )
+
     meta = get_yaml().load(meta_str.replace("@@backend@@", backend))
     if remove_top_level:
         meta.pop("requirements", None)
@@ -3076,13 +3093,16 @@ def test_hint_pip_no_build_backend(
             outputs_to_add.replace("@@backend@@", backend)
         )
 
-    total_expected_hints = _expected_hints + outputs_expected_hints
+    if skip:
+        total_expected_hints = []
+    else:
+        total_expected_hints = _expected_hints + outputs_expected_hints
 
     lints = []
     hints = []
     linter.run_conda_forge_specific(
         meta,
-        None,
+        str(tmp_path),
         lints,
         hints,
         recipe_version=0,