re-allow decorated one-liners

pycodestyle.py

@@ -314,6 +314,41 @@ def maximum_line_length(physical_line, max_line_length, multiline,
 ########################################################################
 
 
+def _is_one_liner(logical_line, indent_level, lines, line_number):
+    if not STARTSWITH_TOP_LEVEL_REGEX.match(logical_line):
+        return False
+
+    line_idx = line_number - 1
+
+    if line_idx < 1:
+        prev_indent = 0
+    else:
+        prev_indent = expand_indent(lines[line_idx - 1])
+
+    if prev_indent > indent_level:
+        return False
+
+    while line_idx < len(lines):
+        line = lines[line_idx].strip()
+        if not line.startswith('@') and STARTSWITH_TOP_LEVEL_REGEX.match(line):
+            break
+        else:
+            line_idx += 1
+    else:
+        return False  # invalid syntax: EOF while searching for def/class
+
+    next_idx = line_idx + 1
+    while next_idx < len(lines):
+        if lines[next_idx].strip():
+            break
+        else:
+            next_idx += 1
+    else:
+        return True  # line is last in the file
+
+    return expand_indent(lines[next_idx]) <= indent_level
+
+
 @register_check
 def blank_lines(logical_line, blank_lines, indent_level, line_number,
                 blank_before, previous_logical,
@@ -360,16 +395,11 @@ 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. this is not a decorator and 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 (not logical_line.startswith("@") and
-                expand_indent(prev_line) <= indent_level and
-                expand_indent(next_line) <= indent_level):
+        # allow a group of one-liners
+        if (
+            _is_one_liner(logical_line, indent_level, lines, line_number) and
+            blank_before == 0
+        ):
             return
         if indent_level:
             if not (blank_before == method_lines or

testsuite/E30not.py

@@ -177,6 +177,32 @@ def foo():
     # for no E30x being emitted.
     def bar(): pass
     def baz(): pass
+#: E704:8:1 E704:10:1
+from typing import overload
+from typing import Union
+
+
+# This emits the (ignored-by-default) E704, but here we're testing
+# for no E30x being emitted.
+@overload
+def f(x: int) -> int: ...
+@overload
+def f(x: str) -> str: ...
+
+
+def f(x: Union[int, str]) -> Union[int, str]:
+    return x
+#: E704:8:5 E704:10:5
+from typing import Protocol
+
+
+class C(Protocol):
+    # This emits the (ignored-by-default) E704, but here we're testing
+    # for no E30x being emitted.
+    @property
+    def f(self) -> int: ...
+    @property
+    def g(self) -> str: ...
 #: Okay
 #!python
 # -*- coding: utf-8 -*-