Split ternary expressions

Fixes #141

README.md

@@ -540,6 +540,8 @@ More details can be found in [CONTRIBUTING](CONTRIBUTING.md).
 
 * fixed invalid splitting on comma in lambda arguments (#133)
 
+* fixed missing splits of ternary expressions (#141)
+
 ### 18.4a2
 
 * fixed parsing of unaligned standalone comments (#99, #112)

black.py

@@ -583,6 +583,7 @@ def show(cls, code: str) -> None:
 }
 COMPREHENSION_PRIORITY = 20
 COMMA_PRIORITY = 10
+TERNARY_PRIORITY = 7
 LOGIC_PRIORITY = 5
 STRING_PRIORITY = 4
 COMPARATOR_PRIORITY = 3
@@ -1602,6 +1603,14 @@ def is_split_before_delimiter(leaf: Leaf, previous: Leaf = None) -> int:
     ):
         return COMPREHENSION_PRIORITY
 
+    if (
+        leaf.type == token.NAME
+        and leaf.value in {"if", "else"}
+        and leaf.parent
+        and leaf.parent.type == syms.test
+    ):
+        return TERNARY_PRIORITY
+
     if leaf.type == token.NAME and leaf.value in LOGIC_OPERATORS and leaf.parent:
         return LOGIC_PRIORITY
 

tests/expression.diff

@@ -11,7 +11,7 @@
  True
  False
  1
-@@ -29,60 +29,78 @@
+@@ -29,61 +29,83 @@
  ~great
  +value
  -1
@@ -37,8 +37,14 @@
  (str or None) if True else (str or bytes or None)
  str or None if (1 if True else 2) else str or bytes or None
  (str or None) if (1 if True else 2) else (str or bytes or None)
+-((super_long_variable_name or None) if (1 if super_long_test_name else 2) else (str or bytes or None))
 -{'2.7': dead, '3.7': (long_live or die_hard)}
 -{'2.7': dead, '3.7': (long_live or die_hard), **{'3.6': verygood}}
++(
++    (super_long_variable_name or None)
++    if (1 if super_long_test_name else 2)
++    else (str or bytes or None)
++)
 +{"2.7": dead, "3.7": (long_live or die_hard)}
 +{"2.7": dead, "3.7": (long_live or die_hard), **{"3.6": verygood}}
  {**a, **b, **c}
@@ -110,7 +116,7 @@
  call(**self.screen_kwargs)
  call(b, **self.screen_kwargs)
  lukasz.langa.pl
-@@ -91,11 +109,11 @@
+@@ -92,11 +114,11 @@
  1.0 .real
  ....__class__
  list[str]
@@ -123,7 +129,7 @@
  ]
  slice[0]
  slice[0:1]
-@@ -122,88 +140,122 @@
+@@ -123,88 +145,122 @@
  numpy[-(c + 1):, d]
  numpy[:, l[-2]]
  numpy[:, ::-1]

tests/expression.py

@@ -43,6 +43,7 @@
 (str or None) if True else (str or bytes or None)
 str or None if (1 if True else 2) else str or bytes or None
 (str or None) if (1 if True else 2) else (str or bytes or None)
+((super_long_variable_name or None) if (1 if super_long_test_name else 2) else (str or bytes or None))
 {'2.7': dead, '3.7': (long_live or die_hard)}
 {'2.7': dead, '3.7': (long_live or die_hard), **{'3.6': verygood}}
 {**a, **b, **c}
@@ -260,6 +261,11 @@ async def f():
 (str or None) if True else (str or bytes or None)
 str or None if (1 if True else 2) else str or bytes or None
 (str or None) if (1 if True else 2) else (str or bytes or None)
+(
+    (super_long_variable_name or None)
+    if (1 if super_long_test_name else 2)
+    else (str or bytes or None)
+)
 {"2.7": dead, "3.7": (long_live or die_hard)}
 {"2.7": dead, "3.7": (long_live or die_hard), **{"3.6": verygood}}
 {**a, **b, **c}