From d7cd43d219d57fbf2050a29e4ee2a8262f942679 2020-01-31 22:25:57
From: Matthias Bussonnier <bussonniermatthias@gmail.com>
Date: 2020-01-31 22:25:57
Subject: [PATCH] Merge pull request #12099 from eric-wieser/patch-1

Start multi-line __repr__s on their own line
---

diff --git a/IPython/lib/pretty.py b/IPython/lib/pretty.py
index 49c76ad..50cec70 100644
--- a/IPython/lib/pretty.py
+++ b/IPython/lib/pretty.py
@@ -196,19 +196,22 @@ class PrettyPrinter(_PrettyPrinterBase):
         self.group_queue = GroupQueue(root_group)
         self.indentation = 0
 
+    def _break_one_group(self, group):
+        while group.breakables:
+            x = self.buffer.popleft()
+            self.output_width = x.output(self.output, self.output_width)
+            self.buffer_width -= x.width
+        while self.buffer and isinstance(self.buffer[0], Text):
+            x = self.buffer.popleft()
+            self.output_width = x.output(self.output, self.output_width)
+            self.buffer_width -= x.width
+
     def _break_outer_groups(self):
         while self.max_width < self.output_width + self.buffer_width:
             group = self.group_queue.deq()
             if not group:
                 return
-            while group.breakables:
-                x = self.buffer.popleft()
-                self.output_width = x.output(self.output, self.output_width)
-                self.buffer_width -= x.width
-            while self.buffer and isinstance(self.buffer[0], Text):
-                x = self.buffer.popleft()
-                self.output_width = x.output(self.output, self.output_width)
-                self.buffer_width -= x.width
+            self._break_one_group(group)
 
     def text(self, obj):
         """Add literal text to the output."""
@@ -248,6 +251,9 @@ class PrettyPrinter(_PrettyPrinterBase):
         """
         Explicitly insert a newline into the output, maintaining correct indentation.
         """
+        group = self.group_queue.deq()
+        if group:
+            self._break_one_group(group)
         self.flush()
         self.output.write(self.newline)
         self.output.write(' ' * self.indentation)
@@ -687,10 +693,12 @@ def _repr_pprint(obj, p, cycle):
     """A pprint that just redirects to the normal repr function."""
     # Find newlines and replace them with p.break_()
     output = repr(obj)
-    for idx,output_line in enumerate(output.splitlines()):
-        if idx:
-            p.break_()
-        p.text(output_line)
+    lines = output.splitlines()
+    with p.group():
+        for idx, output_line in enumerate(lines):
+            if idx:
+                p.break_()
+            p.text(output_line)
 
 
 def _function_pprint(obj, p, cycle):
diff --git a/IPython/lib/tests/test_pretty.py b/IPython/lib/tests/test_pretty.py
index cd9fb36..695012d 100644
--- a/IPython/lib/tests/test_pretty.py
+++ b/IPython/lib/tests/test_pretty.py
@@ -68,11 +68,6 @@ class BreakingRepr(object):
     def __repr__(self):
         return "Breaking(\n)"
 
-class BreakingReprParent(object):
-    def _repr_pretty_(self, p, cycle):
-        with p.group(4,"TG: ",":"):
-            p.pretty(BreakingRepr())
-
 class BadRepr(object):
     
     def __repr__(self):
@@ -151,8 +146,12 @@ def test_pprint_break_repr():
     """
     Test that p.break_ is used in repr
     """
-    output = pretty.pretty(BreakingReprParent())
-    expected = "TG: Breaking(\n    ):"
+    output = pretty.pretty([[BreakingRepr()]])
+    expected = "[[Breaking(\n  )]]"
+    nt.assert_equal(output, expected)
+
+    output = pretty.pretty([[BreakingRepr()]*2])
+    expected = "[[Breaking(\n  ),\n  Breaking(\n  )]]"
     nt.assert_equal(output, expected)
 
 def test_bad_repr():