Add previous_unindented_logical_line attribute

This attribute is introduced in pycodestyle 2.1.0

Closes #246

See: PyCQA/pycodestyle#400

docs/source/plugin-development/plugin-parameters.rst

@@ -38,6 +38,7 @@ a file, a plugin can ask for any of the following:
 - :attr:`~flake8.processor.FileProcessor.noqa`
 - :attr:`~flake8.processor.FileProcessor.previous_indent_level`
 - :attr:`~flake8.processor.FileProcessor.previous_logical`
+- :attr:`~flake8.processor.FileProcessor.previous_unindented_logical_line`
 - :attr:`~flake8.processor.FileProcessor.tokens`
 
 Some properties are set once per file for plugins which iterate itself over

src/flake8/processor.py

@@ -41,6 +41,7 @@ class FileProcessor(object):
     - :attr:`noqa`
     - :attr:`previous_indent_level`
     - :attr:`previous_logical`
+    - :attr:`previous_unindented_logical_line`
     - :attr:`tokens`
     - :attr:`file_tokens`
     - :attr:`total_lines`
@@ -89,6 +90,8 @@ def __init__(self, filename, options, lines=None):
         self.previous_indent_level = 0
         #: Previous logical line
         self.previous_logical = ''
+        #: Previous unindented (i.e. top-level) logical line
+        self.previous_unindented_logical_line = ''
         #: Current set of tokens
         self.tokens = []
         #: Total number of lines in the file
@@ -163,6 +166,8 @@ def next_logical_line(self):
         if self.logical_line:
             self.previous_indent_level = self.indent_level
             self.previous_logical = self.logical_line
+            if not self.indent_level:
+                self.previous_unindented_logical_line = self.logical_line
         self.blank_lines = 0
         self.tokens = []
         self.noqa = False