result: keep original traceback and reraise with it

changelog/504.bugfix.rst

@@ -0,0 +1 @@
+Fix a regression in pluggy 1.1.0 where using :func:`result.get_result() <pluggy.Result.get_result>` on the same failed :class:`~pluggy.Result` causes the exception's traceback to get longer and longer.

src/pluggy/_callers.py

@@ -136,7 +136,7 @@ def _multicall(
                 _raise_wrapfail(teardown, "has second yield")  # type: ignore[arg-type]
 
             if exception is not None:
-                raise exception.with_traceback(exception.__traceback__)
+                raise exception
             else:
                 return result
 

src/pluggy/_result.py

@@ -28,7 +28,7 @@ class Result(Generic[ResultType]):
     """An object used to inspect and set the result in a :ref:`hook wrapper
     <hookwrappers>`."""
 
-    __slots__ = ("_result", "_exception")
+    __slots__ = ("_result", "_exception", "_traceback")
 
     def __init__(
         self,
@@ -38,6 +38,8 @@ def __init__(
         """:meta private:"""
         self._result = result
         self._exception = exception
+        # Exception __traceback__ is mutable, this keeps the original.
+        self._traceback = exception.__traceback__ if exception is not None else None
 
     @property
     def excinfo(self) -> _ExcInfo | None:
@@ -46,7 +48,7 @@ def excinfo(self) -> _ExcInfo | None:
         if exc is None:
             return None
         else:
-            return (type(exc), exc, exc.__traceback__)
+            return (type(exc), exc, self._traceback)
 
     @property
     def exception(self) -> BaseException | None:
@@ -75,6 +77,7 @@ def force_result(self, result: ResultType) -> None:
         """
         self._result = result
         self._exception = None
+        self._traceback = None
 
     def force_exception(self, exception: BaseException) -> None:
         """Force the result to fail with ``exception``.
@@ -85,6 +88,7 @@ def force_exception(self, exception: BaseException) -> None:
         """
         self._result = None
         self._exception = exception
+        self._traceback = exception.__traceback__ if exception is not None else None
 
     def get_result(self) -> ResultType:
         """Get the result(s) for this hook call.
@@ -94,10 +98,11 @@ def get_result(self) -> ResultType:
         """
         __tracebackhide__ = True
         exc = self._exception
+        tb = self._traceback
         if exc is None:
             return cast(ResultType, self._result)
         else:
-            raise exc.with_traceback(exc.__traceback__)
+            raise exc.with_traceback(tb)
 
 
 # Historical name (pluggy<=1.2), kept for backward compatibility.

testing/test_result.py

@@ -0,0 +1,27 @@
+import traceback
+
+from pluggy import Result
+
+
+def test_exceptions_traceback_doesnt_get_longer_and_longer() -> None:
+    def bad() -> None:
+        1 / 0
+
+    result = Result.from_call(bad)
+
+    try:
+        result.get_result()
+    except Exception as exc:
+        tb1 = traceback.extract_tb(exc.__traceback__)
+
+    try:
+        result.get_result()
+    except Exception as exc:
+        tb2 = traceback.extract_tb(exc.__traceback__)
+
+    try:
+        result.get_result()
+    except Exception as exc:
+        tb3 = traceback.extract_tb(exc.__traceback__)
+
+    assert len(tb1) == len(tb2) == len(tb3)