Fixed handling of invalid regex pattern

src/_pytest/python_api.py

@@ -1,31 +1,32 @@
 # mypy: allow-untyped-defs
 from __future__ import annotations
 
-from collections.abc import Collection
-from collections.abc import Sized
-from decimal import Decimal
 import math
-from numbers import Complex
 import pprint
+import re
+from collections.abc import Collection, Sized
+from decimal import Decimal
+from numbers import Complex
 from types import TracebackType
-from typing import Any
+from typing import (
-from typing import Callable
+    TYPE_CHECKING,
-from typing import cast
+    Any,
-from typing import ContextManager
+    Callable,
-from typing import final
+    ContextManager,
-from typing import Mapping
+    Mapping,
-from typing import overload
+    Pattern,
-from typing import Pattern
+    Sequence,
-from typing import Sequence
+    Tuple,
-from typing import Tuple
+    Type,
-from typing import Type
+    TypeVar,
-from typing import TYPE_CHECKING
+    cast,
-from typing import TypeVar
+    final,
+    overload,
+)
 
 import _pytest._code
 from _pytest.outcomes import fail
 
-
 if TYPE_CHECKING:
     from numpy import ndarray
 
@@ -1006,6 +1007,9 @@ class RaisesContext(ContextManager[_pytest._code.ExceptionInfo[E]]):
         # Cast to narrow the exception type now that it's verified.
         exc_info = cast(Tuple[Type[E], E, TracebackType], (exc_type, exc_val, exc_tb))
         self.excinfo.fill_unfilled(exc_info)
-        if self.match_expr is not None:
+        try:
-            self.excinfo.match(self.match_expr)
+            if self.match_expr:
+                self.excinfo.match(self.match_expr)
+        except re.error as e:
+            fail(f"Invalid regex pattern provided to 'match': {e}")
         return True

testing/python/raises.py

@@ -6,6 +6,7 @@ import sys
 
 from _pytest.outcomes import Failed
 from _pytest.pytester import Pytester
+
 import pytest
 
 
@@ -132,6 +133,26 @@ class TestRaises:
         result = pytester.runpytest()
         result.stdout.fnmatch_lines(["*2 failed*"])
 
+    def test_raises_with_invalid_regex(self, pytester: Pytester) -> None:
+        pytester.makepyfile(
+            """
+            import pytest
+            
+            def test_invalid_regex():
+                with pytest.raises(ValueError, match="invalid regex character ["):
+                    raise ValueError()
+            """
+        )
+        result = pytester.runpytest()
+        result.stdout.fnmatch_lines(
+            [
+                "*Invalid regex pattern provided to 'match': unterminated character set at position 24*",
+            ]
+        )
+        result.stdout.no_fnmatch_line("*Traceback*")
+        result.stdout.no_fnmatch_line("*File*")
+        result.stdout.no_fnmatch_line("*line*")
+
     def test_noclass(self) -> None:
         with pytest.raises(TypeError):
             pytest.raises("wrong", lambda: None)  # type: ignore[call-overload]