gyp: use "is" when comparing to None

PR-URL: #1860
Reviewed-By: Christian Clauss <cclauss@me.com>
Reviewed-By: Rod Vagg <r@va.gg>

gyp/pylib/gyp/generator/ninja.py

@@ -726,7 +726,7 @@ def cygwin_munge(path):
  elif var == 'name':
  extra_bindings.append(('name', cygwin_munge(basename)))
  else:
- assert var == None, repr(var)
+ assert var is None, repr(var)
 
  outputs = [self.GypPathToNinja(o, env) for o in outputs]
  if self.flavor == 'win':

gyp/pylib/gyp/generator/xcode.py

@@ -539,7 +539,7 @@ def ExpandXcodeVariables(string, expansions):
  """
 
  matches = _xcode_variable_re.findall(string)
- if matches == None:
+ if matches is None:
  return string
 
  matches.reverse()

gyp/pylib/gyp/input.py

@@ -155,7 +155,7 @@ def GetIncludedBuildFiles(build_file_path, aux_data, included=None):
  in the list will be relative to the current directory.
  """
 
- if included == None:
+ if included is None:
  included = []
 
  if build_file_path in included:
@@ -1062,7 +1062,7 @@ def EvalCondition(condition, conditions_key, phase, variables, build_file):
  else:
  false_dict = None
  i = i + 2
- if result == None:
+ if result is None:
  result = EvalSingleCondition(
  cond_expr, true_dict, false_dict, phase, variables, build_file)
 
@@ -1603,7 +1603,7 @@ def Visit(node, path):
 
  def DirectDependencies(self, dependencies=None):
  """Returns a list of just direct dependencies."""
- if dependencies == None:
+ if dependencies is None:
  dependencies = []
 
  for dependency in self.dependencies:
@@ -1631,7 +1631,7 @@ def _AddImportedDependencies(self, targets, dependencies=None):
  public entry point.
  """
 
- if dependencies == None:
+ if dependencies is None:
  dependencies = []
 
  index = 0