Fixed bare raise and exception chaining when a handler raises an exception

CHANGES.rst

@@ -7,6 +7,10 @@ This library adheres to `Semantic Versioning 2.0 <http://semver.org/>`_.
 - `catch()` now raises a `TypeError` if passed an async exception handler instead of
   just giving a `RuntimeWarning` about the coroutine never being awaited. (#66, PR by
   John Litborn)
+- Fixed plain ``raise`` statement in an exception handler callback to work like a
+  ``raise`` in an ``except*`` block
+- Fixed new exception group not being chained to the original exception when raising an
+  exception group from exceptions raised in handler callbacks
 
 **1.1.2**
 

src/exceptiongroup/_catch.py

@@ -34,7 +34,7 @@ def __exit__(
             elif unhandled is None:
                 return True
             else:
-                raise unhandled from None
+                raise unhandled from exc
 
         return False
 
@@ -50,7 +50,10 @@ def handle_exception(self, exc: BaseException) -> BaseException | None:
             matched, excgroup = excgroup.split(exc_types)
             if matched:
                 try:
-                    result = handler(matched)
+                    try:
+                        raise matched
+                    except BaseExceptionGroup:
+                        result = handler(matched)
                 except BaseException as new_exc:
                     new_exceptions.append(new_exc)
                 else:

tests/test_catch.py

@@ -153,6 +153,21 @@ def handler(exc):
             raise ExceptionGroup("booboo", [ValueError("bar")])
 
 
+def test_catch_handler_reraises():
+    def handler(exc):
+        raise
+
+    with pytest.raises(ExceptionGroup) as exc:
+        with catch({(ValueError,): handler, (RuntimeError,): lambda eg: None}):
+            original_exc = ExceptionGroup("booboo", [ValueError("bar"), RuntimeError()])
+            raise original_exc
+
+    assert len(exc.value.exceptions) == 1
+    assert isinstance(exc.value.exceptions[0], ValueError)
+    assert str(exc.value.exceptions[0]) == "bar"
+    assert exc.value.__cause__ is original_exc
+
+
 def test_catch_subclass():
     lookup_errors = []
     with catch({LookupError: lookup_errors.append}):