feat: add validation for shortest import names to ensure parent packages are included

Author: finswimmer

src/poetry/core/factory.py

@@ -345,6 +345,45 @@ def _validate_import_names(
                 f"Import names found in both import-names and import-namespaces: {', '.join(duplicates)}"
             )
 
+        cls._validate_shortest_import_names(
+            import_names, import_type="import-names", result=result
+        )
+        cls._validate_shortest_import_names(
+            import_namespaces, import_type="import-namespaces", result=result
+        )
+
+    @classmethod
+    def _validate_shortest_import_names(
+        cls,
+        import_names: set[str],
+        import_type: Literal["import-names", "import-namespaces"],
+        result: dict[str, list[str]],
+    ) -> None:
+        """
+        Validate that every import name includes its parent package names.
+
+        For each entry in `import_names`, ensure every parent package up to the
+        top-level package is present in `import_names`. If a parent package is
+        missing, a warning is appended to `result["warnings"]`. The
+        `import_type` parameter is interpolated into the warning to indicate
+        whether the context is `import-names` or `import-namespaces`.
+        """
+        for import_name in import_names:
+            if "." in import_name:
+                parent: str | None = import_name.rsplit(".", maxsplit=1)[0]
+
+                while parent:
+                    if parent not in import_names:
+                        base = parent.split(".", maxsplit=1)[0]
+                        result["warnings"].append(
+                            f"Import name '{import_name}' should have all its parents up to '{base}' included in {import_type}."
+                        )
+                        break
+
+                    parent = (
+                        parent.rsplit(".", maxsplit=1)[0] if "." in parent else None
+                    )
+
     @classmethod
     def _configure_entry_points(
         cls,

tests/test_factory.py

@@ -391,6 +391,44 @@ def test_create_poetry_raise_on_empty_import_namespaces(tmp_path: Path) -> None:
         _ = Factory().create_poetry(pyproject)
 
 
+def test_create_poetry_raise_warning_on_shortest_import_names_not_listed(
+    caplog: LogCaptureFixture, tmp_path: Path
+) -> None:
+    content = """
+    [project]
+    name = "my-package"
+    version = "1.2.3"
+    description = "Some description."
+    requires-python = ">=3.6"
+
+    import-names = ["anotherpackage", "my_package.foo.bar", "foo.bar.baz"]
+    import-namespaces = ["namespace.foo", "another_namespace"]
+
+    dependencies = []
+    """
+
+    pyproject = tmp_path / "pyproject.toml"
+    pyproject.write_text(content)
+
+    _ = Factory().create_poetry(pyproject)
+
+    assert (
+        "Import name 'foo.bar.baz' should have all its parents up to 'foo' included in import-names."
+        in caplog.text
+    )
+    assert (
+        "Import name 'my_package.foo.bar' should have all its parents up to 'my_package' included in import-names."
+        in caplog.text
+    )
+    assert (
+        "Import name 'namespace.foo' should have all its parents up to 'namespace' included in import-namespaces."
+        in caplog.text
+    )
+
+    assert "anotherpackage" not in caplog.text
+    assert "another_namespace" not in caplog.text
+
+
 @pytest.mark.parametrize(
     "project", ["sample_project_with_groups", "sample_project_with_groups_new"]
 )