From 324eddd415640132c8d599479dddc5bb5768099d 2017-12-21 11:46:28
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: 2017-12-21 11:46:28
Subject: [PATCH] Don't sort dicts for display in Python >= 3.7

Closes gh-10110

---

diff --git a/IPython/lib/pretty.py b/IPython/lib/pretty.py
index cbbb726..6787d38 100644
--- a/IPython/lib/pretty.py
+++ b/IPython/lib/pretty.py
@@ -95,6 +95,7 @@ __all__ = ['pretty', 'pprint', 'PrettyPrinter', 'RepresentationPrinter',
 
 
 MAX_SEQ_LENGTH = 1000
+DICT_IS_ORDERED = sys.version_info >= (3, 7)
 _re_pattern_type = type(re.compile(''))
 
 def _safe_getattr(obj, attr, default=None):
@@ -613,7 +614,9 @@ def _dict_pprinter_factory(start, end, basetype=None):
         p.begin_group(step, start)
         keys = obj.keys()
         # if dict isn't large enough to be truncated, sort keys before displaying
-        if not (p.max_seq_length and len(obj) >= p.max_seq_length):
+        # From Python 3.7, dicts preserve order by definition, so we don't sort.
+        if not DICT_IS_ORDERED \
+                and not (p.max_seq_length and len(obj) >= p.max_seq_length):
             keys = _sorted_for_pprint(keys)
         for idx, key in p._enumerate(keys):
             if idx: