Do not enforce empty lines after control flow statements

Fixes #90

README.md

@@ -218,10 +218,7 @@ bother you if you overdo it by a few km/h".
 
 *Black* avoids spurious vertical whitespace.  This is in the spirit of
 PEP 8 which says that in-function vertical whitespace should only be
-used sparingly.  One exception is control flow statements: *Black* will
-always emit an extra empty line after ``return``, ``raise``, ``break``,
-``continue``, and ``yield``.  This is to make changes in control flow
-more prominent to readers of your code.
+used sparingly.
 
 *Black* will allow single empty lines inside functions, and single and
 double empty lines on module level left by the original editors, except
@@ -528,6 +525,9 @@ More details can be found in [CONTRIBUTING](CONTRIBUTING.md).
 * generalized star expression handling, including double stars; this
   fixes multiplication making expressions "unsafe" for trailing commas (#132)
 
+* Black no longer enforces putting empty lines behind control flow statements
+  (#90)
+
 * fixed comment indentation when a standalone comment closes a block (#16, #32)
 
 * fixed standalone comments receiving extra empty lines if immediately preceding

black.py

@@ -1056,9 +1056,6 @@ def _maybe_empty_lines(self, current_line: Line) -> Tuple[int, int]:
                 newlines -= 1
             return newlines, 0
 
-        if current_line.is_flow_control:
-            return before, 1
-
         if (
             self.previous_line
             and self.previous_line.is_import
@@ -1067,13 +1064,6 @@ def _maybe_empty_lines(self, current_line: Line) -> Tuple[int, int]:
         ):
             return (before or 1), 0
 
-        if (
-            self.previous_line
-            and self.previous_line.is_yield
-            and (not current_line.is_yield or depth != self.previous_line.depth)
-        ):
-            return (before or 1), 0
-
         return before, 0
 
 

tests/expression.diff

@@ -129,7 +129,7 @@
  ]
  slice[0]
  slice[0:1]
-@@ -123,88 +145,122 @@
+@@ -123,88 +145,114 @@
  numpy[-(c + 1):, d]
  numpy[:, l[-2]]
  numpy[:, ::-1]
@@ -190,10 +190,9 @@
 +
  def gen():
      yield from outside_of_generator
-+
      a = (yield)
-+
  
++
  async def f():
      await some.complicated[0].call(with_args=(True or (1 is not 1)))
 -print(* [] or [1])
@@ -242,8 +241,6 @@
 -if (
 -    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa /
 -    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
--):
--    return True
 +print(*lambda x: x)
 +for (x,) in (1,), (2,), (3,):
 +    ...
@@ -263,42 +260,35 @@
 +    or signal.getsignal(signal.SIGINT) != signal.default_int_handler
 +):
 +    return True
-+
 +if (
 +    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 +    | aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 +):
 +    return True
-+
 +if (
 +    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 +    & aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 +):
 +    return True
-+
 +if (
 +    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 +    + aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 +):
 +    return True
-+
 +if (
 +    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 +    - aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 +):
 +    return True
-+
 +if (
 +    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 +    * aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 +):
 +    return True
-+
 +if (
 +    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 +    / aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
-+):
-+    return True
-+
+ ):
+     return True
  last_call()
  # standalone comment at ENDMARKER

tests/expression.py

@@ -409,7 +409,6 @@ async def f():
 
 def gen():
     yield from outside_of_generator
-
     a = (yield)
 
 
@@ -438,42 +437,35 @@ async def f():
     or signal.getsignal(signal.SIGINT) != signal.default_int_handler
 ):
     return True
-
 if (
     aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
     | aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 ):
     return True
-
 if (
     aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
     & aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 ):
     return True
-
 if (
     aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
     + aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 ):
     return True
-
 if (
     aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
     - aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 ):
     return True
-
 if (
     aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
     * aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 ):
     return True
-
 if (
     aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
     / aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 ):
     return True
-
 last_call()
 # standalone comment at ENDMARKER

tests/function.py

@@ -102,13 +102,11 @@ def func_no_args():
     c
     if True:
         raise RuntimeError
-
     if False:
         ...
     for i in range(10):
         print(i)
         continue
-
     exec("new-style exec", {}, {})
     return None