From f35c2f2baad42c9b1457b5578efeeeb49398e010 Mon Sep 17 00:00:00 2001
From: Kadir Can Ozden <101993364+bysiber@users.noreply.github.com>
Date: Fri, 20 Feb 2026 05:26:51 +0300
Subject: [PATCH 1/2] code: use current excinfo when formatting chained
 BaseExceptionGroup

In repr_excinfo, the BaseExceptionGroup branch incorrectly uses
the original excinfo instead of excinfo_ (which tracks the current
exception in the chain). This means that when walking __cause__ or
__context__ chains, filter_excinfo_traceback and format_exception
always operate on the first exception rather than the current one.

The non-group branch on the else side already uses excinfo_
correctly.
---
 src/_pytest/_code/code.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/_pytest/_code/code.py b/src/_pytest/_code/code.py
index 4cf99a77340..67ccc2ac661 100644
--- a/src/_pytest/_code/code.py
+++ b/src/_pytest/_code/code.py
@@ -1188,11 +1188,11 @@ def repr_excinfo(self, excinfo: ExceptionInfo[BaseException]) -> ExceptionChainR
                 reprtraceback: ReprTraceback | ReprTracebackNative
                 if isinstance(e, BaseExceptionGroup):
                     # don't filter any sub-exceptions since they shouldn't have any internal frames
-                    traceback = filter_excinfo_traceback(self.tbfilter, excinfo)
+                    traceback = filter_excinfo_traceback(self.tbfilter, excinfo_)
                     reprtraceback = ReprTracebackNative(
                         format_exception(
-                            type(excinfo.value),
-                            excinfo.value,
+                            type(excinfo_.value),
+                            excinfo_.value,
                             traceback[0]._rawentry if traceback else None,
                         )
                     )

From 66d902b02b59ecb99b3967c5e711cd42eff919d8 Mon Sep 17 00:00:00 2001
From: Kadir Can Ozden <101993364+bysiber@users.noreply.github.com>
Date: Fri, 20 Feb 2026 15:49:10 +0300
Subject: [PATCH 2/2] Add regression test for chained ExceptionGroup using
 wrong excinfo

Test that when a BaseExceptionGroup appears as a chained exception,
the traceback output correctly shows both the ExceptionGroup and the
outer exception, using the current excinfo_ rather than the original.
---
 testing/code/test_excinfo.py | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/testing/code/test_excinfo.py b/testing/code/test_excinfo.py
index 70499fec893..4c0d67fac37 100644
--- a/testing/code/test_excinfo.py
+++ b/testing/code/test_excinfo.py
@@ -2009,3 +2009,35 @@ def test_check_error_notes_failure(
     with pytest.raises(AssertionError):
         with pytest.raises(type(error), match=match):
             raise error
+
+
+def test_chained_exceptiongroup_uses_current_excinfo(pytester: Pytester) -> None:
+    """Regression test: when a BaseExceptionGroup appears as a chained exception,
+    repr_excinfo should use excinfo_ (current) not excinfo (original outer).
+
+    With the bug, the traceback and type info from the outer exception was used
+    instead of the chained ExceptionGroup, potentially causing wrong output or
+    a mismatch between the displayed exception type and its traceback.
+    """
+    pytester.makepyfile(
+        """
+        import sys
+        if sys.version_info < (3, 11):
+            from exceptiongroup import ExceptionGroup
+
+        def test_chained_eg():
+            try:
+                raise ExceptionGroup("inner", [TypeError("from inner")])
+            except BaseException:
+                raise ValueError("outer")
+        """
+    )
+    result = pytester.runpytest()
+    result.stdout.fnmatch_lines(
+        [
+            "*ExceptionGroup*",
+            "*TypeError: from inner*",
+            "*During handling of the above exception, another exception occurred:*",
+            "*ValueError: outer*",
+        ]
+    )