Support `Private ::` trove classifiers (#7271)

src/poetry/console/commands/check.py

@@ -31,6 +31,10 @@ class CheckCommand(Command):
         unrecognized = sorted(
             project_classifiers - set(classifiers) - set(deprecated_classifiers)
         )
+        # Allow "Private ::" classifiers as recommended on PyPI and the packaging guide
+        # to allow users to avoid accidentally publishing private packages to PyPI.
+        # https://pypi.org/classifiers/
+        unrecognized = [u for u in unrecognized if not u.startswith("Private ::")]
         if unrecognized:
             errors.append(f"Unrecognized classifiers: {unrecognized!r}.")
 

tests/console/commands/test_check.py

@@ -59,3 +59,21 @@ Warning: Deprecated classifier\
 """
 
     assert tester.io.fetch_error() == expected
+
+
+def test_check_private(mocker: MockerFixture, tester: CommandTester):
+    mocker.patch(
+        "poetry.factory.Factory.locate",
+        return_value=Path(__file__).parent.parent.parent
+        / "fixtures"
+        / "private_pyproject"
+        / "pyproject.toml",
+    )
+
+    tester.execute()
+
+    expected = """\
+All set!
+"""
+
+    assert tester.io.fetch_output() == expected

tests/fixtures/private_pyproject/pyproject.toml

+[tool.poetry]
+name = "private"
+version = "0.1.0"
+description = ""
+authors = ["Your Name <you@example.com>"]
+readme = "README.md"
+classifiers = [
+    "Private :: Do Not Upload",
+]
+
+
+[tool.poetry.dependencies]
+python = "^3.7"
+
+[build-system]
+requires = ["poetry-core"]
+build-backend = "poetry.core.masonry.api"