Stop failing if mypy only produces notes

dmtucker · dmtucker · commit 155151ce31fc · 2022-11-27T11:09:47.000-08:00
diff --git a/src/pytest_mypy.py b/src/pytest_mypy.py
@@ -5,6 +5,7 @@
 from pathlib import Path
 from tempfile import NamedTemporaryFile
 from typing import Dict, List, Optional, TextIO
+import warnings
 
 import attr
 from filelock import FileLock  # type: ignore
@@ -202,7 +203,12 @@ def runtest(self):
         abspath = os.path.abspath(str(self.fspath))
         errors = results.abspath_errors.get(abspath)
         if errors:
-            raise MypyError(file_error_formatter(self, results, errors))
+            if not all(
+                error.partition(":")[2].partition(":")[0].strip() == "note"
+                for error in errors
+            ):
+                raise MypyError(file_error_formatter(self, results, errors))
+            warnings.warn("\n" + "\n".join(errors), MypyWarning)
 
     def reportinfo(self):
         """Produce a heading for the test report."""
@@ -314,6 +320,10 @@ class MypyError(Exception):
     """
 
 
+class MypyWarning(pytest.PytestWarning):
+    """A non-failure message regarding the mypy run."""
+
+
 def pytest_terminal_summary(terminalreporter, config):
     """Report stderr and unrecognized lines from stdout."""
     try:
diff --git a/tests/test_pytest_mypy.py b/tests/test_pytest_mypy.py
@@ -98,6 +98,33 @@ def pyfunc(x: int) -> str:
     assert result.ret != 0
 
 
+def test_mypy_annotation_unchecked(testdir, xdist_args):
+    """Verify that annotation-unchecked warnings do not manifest as an error."""
+    testdir.makepyfile(
+        """
+            def pyfunc(x):
+                y: int = 2
+                return x * y
+        """,
+    )
+    result = testdir.runpytest_subprocess(*xdist_args)
+    result.assert_outcomes()
+    result = testdir.runpytest_subprocess("--mypy", *xdist_args)
+    mypy_file_checks = 1
+    mypy_status_check = 1
+    mypy_checks = mypy_file_checks + mypy_status_check
+    outcomes = {"passed": mypy_checks}
+    # mypy doesn't emit annotation-unchecked warnings until 0.990:
+    min_mypy_version = Version("0.990")
+    if MYPY_VERSION >= min_mypy_version and PYTEST_VERSION >= Version("7.0"):
+        # assert_outcomes does not support `warnings` until 7.x.
+        outcomes["warnings"] = 1
+    result.assert_outcomes(**outcomes)
+    if MYPY_VERSION >= min_mypy_version:
+        result.stdout.fnmatch_lines(["*MypyWarning*"])
+    assert result.ret == 0
+
+
 def test_mypy_ignore_missings_imports(testdir, xdist_args):
     """
     Verify that --mypy-ignore-missing-imports
