Allow omitting blank lines around one-liner definitions.

Author: anntzer

pycodestyle.py

@@ -354,6 +354,16 @@ def blank_lines(logical_line, blank_lines, indent_level, line_number,
           ):
         yield 0, "E303 too many blank lines (%d)" % blank_lines
     elif STARTSWITH_TOP_LEVEL_REGEX.match(logical_line):
+        # If this is a one-liner (i.e. the next line is not more
+        # indented), and the previous line is also not deeper
+        # (it would be better to check if the previous line is part
+        # of another def/class at the same level), don't require blank
+        # lines around this.
+        prev_line = lines[line_number - 2] if line_number >= 2 else ''
+        next_line = lines[line_number] if line_number < len(lines) else ''
+        if (expand_indent(prev_line) <= indent_level and
+                expand_indent(next_line) <= indent_level):
+            return
         if indent_level:
             if not (blank_before == method_lines or
                     previous_indent_level < indent_level or

testsuite/E30.py

@@ -163,3 +163,21 @@ async  def x():
 
 async  def x(y: int = 1):
     pass
+#: E704:3:1 E302:3:1
+def bar():
+    pass
+def baz(): pass
+#: E704:1:1 E302:2:1
+def bar(): pass
+def baz():
+    pass
+#: E704:4:5 E306:4:5
+def foo():
+    def bar():
+        pass
+    def baz(): pass
+#: E704:2:5 E306:3:5
+def foo():
+    def bar(): pass
+    def baz():
+        pass

testsuite/E30not.py

@@ -162,3 +162,14 @@ class Bar(object):
 def foo(x):
     classification = x
     definitely = not classification
+#: E704:3:1 E704:4:1
+# This emits the (ignored-by-default) E704, but here we're testing
+# for no E30x being emitted.
+def bar(): pass
+def baz(): pass
+#: E704:4:5 E704:5:5
+def foo():
+    # This emits the (ignored-by-default) E704, but here we're testing
+    # for no E30x being emitted.
+    def bar(): pass
+    def baz(): pass