From 8bb589fc5dc4eafffe051d6a665c18d8c5f8c0d2 Mon Sep 17 00:00:00 2001
From: Bruno Oliveira <nicoddemus@gmail.com>
Date: Fri, 9 Jun 2017 18:47:07 -0300
Subject: [PATCH] Fix internal error when trying to detect the start of a
 recursive traceback.

Fix #2486
---
 _pytest/_code/code.py        |  7 +++++--
 changelog/2486.bugfix        |  1 +
 testing/code/test_excinfo.py | 23 +++++++++++++++++++++++
 3 files changed, 29 insertions(+), 2 deletions(-)
 create mode 100644 changelog/2486.bugfix

diff --git a/_pytest/_code/code.py b/_pytest/_code/code.py
index 9b3408dc4..5b7cc4191 100644
--- a/_pytest/_code/code.py
+++ b/_pytest/_code/code.py
@@ -640,8 +640,11 @@ class FormattedExcinfo(object):
             ).format(exc_type=type(e).__name__, exc_msg=safe_str(e), max_frames=max_frames, total=len(traceback))
             traceback = traceback[:max_frames] + traceback[-max_frames:]
         else:
-            extraline = "!!! Recursion detected (same locals & position)"
-            traceback = traceback[:recursionindex + 1]
+            if recursionindex is not None:
+                extraline = "!!! Recursion detected (same locals & position)"
+                traceback = traceback[:recursionindex + 1]
+            else:
+                extraline = None
             
         return traceback, extraline
 
diff --git a/changelog/2486.bugfix b/changelog/2486.bugfix
new file mode 100644
index 000000000..97917197c
--- /dev/null
+++ b/changelog/2486.bugfix
@@ -0,0 +1 @@
+Fix internal error when trying to detect the start of a recursive traceback.
diff --git a/testing/code/test_excinfo.py b/testing/code/test_excinfo.py
index 3128beff8..0b074d64a 100644
--- a/testing/code/test_excinfo.py
+++ b/testing/code/test_excinfo.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 from __future__ import absolute_import, division, print_function
 
+import sys
 import operator
 import _pytest
 import py
@@ -1173,3 +1174,25 @@ def test_exception_repr_extraction_error_on_recursion():
             '*The following exception happened*',
             '*ValueError: The truth value of an array*',
         ])
+
+
+def test_no_recursion_index_on_recursion_error():
+    """
+    Ensure that we don't break in case we can't find the recursion index
+    during a recursion error (#2486).
+    """
+    try:
+        class RecursionDepthError(object):
+            def __getattr__(self, attr):
+                return getattr(self, '_' + attr)
+
+        RecursionDepthError().trigger
+    except:
+        from _pytest._code.code import ExceptionInfo
+        exc_info = ExceptionInfo()
+        if sys.version_info[:2] == (2, 6):
+            assert "'RecursionDepthError' object has no attribute '___" in str(exc_info.getrepr())
+        else:
+            assert 'maximum recursion' in str(exc_info.getrepr())
+    else:
+        assert 0