fix: unknown patches should be errors, not warnings

Author: nedbat

coverage/patch.py

@@ -9,6 +9,8 @@
 
 from typing import NoReturn, TYPE_CHECKING
 
+from coverage.exceptions import ConfigError
+
 if TYPE_CHECKING:
     from coverage import Coverage
     from coverage.config import CoverageConfig
@@ -28,4 +30,4 @@ def _coverage_os_exit_patch(status: int) -> NoReturn:
                 _old_os_exit(status)
             os._exit = _coverage_os_exit_patch
         else:
-            cov._warn(f"Unknown patch {patch!r}, ignored", slug="unknown-patch")
+            raise ConfigError(f"Unknown patch {patch!r}")

doc/cmd.rst

@@ -300,9 +300,6 @@ sys.monitoring doesn't yet support dynamic contexts, using default core (no-sysm
   This isn't supported by coverage.py yet.  A default core will be used
   instead.
 
-Unknown patch 'XYZ', ignored (unknown-patch)
-  You specified an incorrect patch name in the :ref:`config_run_patch` setting.
-
 Individual warnings can be disabled with the :ref:`disable_warnings
 <config_run_disable_warnings>` configuration setting.  It is a list of the
 short parenthetical nicknames in the warning messages.  For example, to silence

tests/test_config.py

@@ -19,7 +19,7 @@
 from coverage.types import FilePathClasses, FilePathType
 
 from tests.coveragetest import CoverageTest, UsingModulesMixin
-from tests.helpers import assert_coverage_warnings
+
 
 class ConfigTest(CoverageTest):
     """Tests of the different sources of configuration settings."""
@@ -477,10 +477,10 @@ def test_unknown_patch(self) -> None:
                 os._exit
                 xyzzy
             """)
-        with pytest.warns(CoverageWarning) as warns:
+        msg = "Unknown patch 'xyzzy'"
+        with pytest.raises(ConfigError, match=msg):
             cov = coverage.Coverage()
             self.start_import_stop(cov, "foo")
-        assert_coverage_warnings(warns, "Unknown patch 'xyzzy', ignored (unknown-patch)")
 
     def test_misplaced_option(self) -> None:
         self.make_file(".coveragerc", """\