From f0474411559622555df0814be3741da9bcfd4d15 2017-08-09 14:46:05
From: Min RK <benjaminrk@gmail.com>
Date: 2017-08-09 14:46:05
Subject: [PATCH] preserve priority of user-registered per-mime renderers

fixes case where `_repr_mimebundle_` had higher priority than custom for_type methods for single mime-types.

---

diff --git a/IPython/core/formatters.py b/IPython/core/formatters.py
index 6dd37c1..82067e1 100644
--- a/IPython/core/formatters.py
+++ b/IPython/core/formatters.py
@@ -159,8 +159,17 @@ class DisplayFormatter(Configurable):
 
         for format_type, formatter in self.formatters.items():
             if format_type in format_dict:
-                # already got it from mimebundle, don't render again
-                continue
+                # already got it from mimebundle, maybe don't render again.
+                # exception: manually registered per-mime renderer
+                # check priority:
+                # 1. user-registered per-mime formatter
+                # 2. mime-bundle (user-registered or repr method)
+                # 3. default per-mime formatter (e.g. repr method)
+                try:
+                    formatter.lookup(obj)
+                except KeyError:
+                    # no special formatter, use mime-bundle-provided value
+                    continue
             if include and format_type not in include:
                 continue
             if exclude and format_type in exclude: