FileProcessor.keyword_arguments_for: Optimize by removing arguments.

Attaching the extra arguments directly to the FileProcessor object
lets us streamline this code for a 6% speedup.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

src/flake8/checker.py

@@ -422,11 +422,11 @@ class FileChecker(object):
         self.results.append((error_code, line_number, column, text, line))
         return error_code
 
-    def run_check(self, plugin, **arguments):
+    def run_check(self, plugin):
         """Run the check in a single plugin."""
         try:
-            self.processor.keyword_arguments_for(
+            arguments = self.processor.keyword_arguments_for(
-                plugin["parameters"], arguments
+                plugin["parameters"]
             )
         except AttributeError as ae:
             LOG.error("Plugin requested unknown parameters.")
@@ -493,8 +493,10 @@ class FileChecker(object):
             )
             return
 
+        self.processor.tree = ast
+
         for plugin in self.checks["ast_plugins"]:
-            checker = self.run_check(plugin, tree=ast)
+            checker = self.run_check(plugin)
             # If the plugin uses a class, call the run method of it, otherwise
             # the call should return something iterable itself
             try:
@@ -509,6 +511,8 @@ class FileChecker(object):
                     text=text,
                 )
 
+        del self.processor.tree
+
     def run_logical_checks(self):
         """Run all checks expecting a logical line."""
         comments, logical_line, mapping = self.processor.build_logical_line()
@@ -520,7 +524,7 @@ class FileChecker(object):
 
         for plugin in self.checks["logical_line_plugins"]:
             self.processor.update_checker_state_for(plugin)
-            results = self.run_check(plugin, logical_line=logical_line) or ()
+            results = self.run_check(plugin) or ()
             for offset, text in results:
                 line_number, column_offset = find_offset(offset, mapping)
                 if line_number == column_offset == 0:
@@ -539,9 +543,11 @@ class FileChecker(object):
 
         A single physical check may return multiple errors.
         """
+        self.processor.physical_line = physical_line
+
         for plugin in self.checks["physical_line_plugins"]:
             self.processor.update_checker_state_for(plugin)
-            result = self.run_check(plugin, physical_line=physical_line)
+            result = self.run_check(plugin)
 
             if result is not None:
                 # This is a single result if first element is an int
@@ -564,6 +570,8 @@ class FileChecker(object):
                         text=text,
                     )
 
+        del self.processor.physical_line
+
     def process_tokens(self):
         """Process tokens and trigger checks.
 

src/flake8/processor.py

@@ -239,18 +239,15 @@ class FileProcessor(object):
             yield line
             self.line_number += 1
 
-    def keyword_arguments_for(self, parameters, arguments=None):
+    def keyword_arguments_for(self, parameters):
-        # type: (Dict[str, bool], Optional[Dict[str, Any]]) -> Dict[str, Any]
+        # type: (Dict[str, bool]) -> Dict[str, Any]
         """Generate the keyword arguments for a list of parameters."""
-        if arguments is None:
+        arguments = {}
-            arguments = {}
+        for param in parameters:
-        for param, required in parameters.items():
-            if param in arguments:
-                continue
             try:
                 arguments[param] = getattr(self, param)
             except AttributeError as exc:
-                if required:
+                if parameters[param]:
                     LOG.exception(exc)
                     raise
                 else:

tests/unit/test_file_processor.py

@@ -188,7 +188,7 @@ def test_next_line(default_options):
 
 @pytest.mark.parametrize('params, args, expected_kwargs', [
     ({'blank_before': True, 'blank_lines': True},
-        None,
+        {},
         {'blank_before': 0, 'blank_lines': 0}),
     ({'noqa': True, 'fake': True},
         {'fake': 'foo'},
@@ -196,8 +196,8 @@ def test_next_line(default_options):
     ({'blank_before': True, 'blank_lines': True, 'noqa': True},
         {'blank_before': 10, 'blank_lines': 5, 'noqa': True},
         {'blank_before': 10, 'blank_lines': 5, 'noqa': True}),
-    ({}, {'fake': 'foo'}, {'fake': 'foo'}),
+    ({'fake': False}, {'fake': 'foo'}, {'fake': 'foo'}),
-    ({'non-existent': False}, {'fake': 'foo'}, {'fake': 'foo'}),
+    ({'fake': False, 'non-existent': False}, {'fake': 'foo'}, {'fake': 'foo'}),
 ])
 def test_keyword_arguments_for(params, args, expected_kwargs, default_options):
     """Verify the keyword args are generated properly."""
@@ -206,7 +206,9 @@ def test_keyword_arguments_for(params, args, expected_kwargs, default_options):
     ])
     kwargs_for = file_processor.keyword_arguments_for
 
-    assert kwargs_for(params, args) == expected_kwargs
+    for k, v in args.items():
+        setattr(file_processor, k, v)
+    assert kwargs_for(params) == expected_kwargs
 
 
 def test_keyword_arguments_for_does_not_handle_attribute_errors(