We cannot fake the descriptor on a tproxy so we have to set _tb_next directly

diff --git a/jinja2/debug.py b/jinja2/debug.py
index e8492cd6711a8ce9779c6eb3efa4aa4152868cd5..80ee2e703fde3023802975426660dd47cf65f9e8 100644 (file)
--- a/jinja2/debug.py
+++ b/jinja2/debug.py
@@ -80,9 +80,9 @@ class ProcessedTraceback(object):
         prev_tb = None
         for tb in self.frames:
             if prev_tb is not None:
-                prev_tb.tb_next = tb
+                prev_tb._tb_next = tb
             prev_tb = tb
-        prev_tb.tb_next = None
+        prev_tb._tb_next = None
 
     def render_as_text(self, limit=None):
         """Return a string with the traceback."""