Here's a patch that adds this functionality to the 'typecheck' checker, and
uses the underscore naming convention (not CamelCase). It also contains a
couple of fixes for bugs in the version that I originally posted.
James.
======================
--- typecheck.py 2009-11-23 14:39:03.000000000 -0800
+++ typecheck.py 2009-11-23 15:10:08.000000000 -0800
@@ -43,6 +43,22 @@
'W1111': ('Assigning to function call which only returns None',
'Used when an assigment is done on a function call but the \
infered function returns nothing but None.'),
+
+ 'E1120': ('No value passed for parameter %s in function call',
+ 'Used when a function call passes too few arguments.'),
+ 'E1121': ('Too many positional arguments for function call',
+ 'Used when a function call passes too many positional \
+ arguments.'),
+ 'E1122': ('Duplicate keyword argument %r in function call',
+ 'Used when a function call passes the same keyword argument \
+ multiple times.'),
+ 'E1123': ('Passing unexpected keyword argument %r in function call',
+ 'Used when a function call passes a keyword argument that \
+ doesn\'t correspond to one of the function\'s parameter
names.'),
+ 'E1124': ('Multiple values passed for parameter %r in function call',
+ 'Used when a function call would result in assigning multiple
\
+ values to a function parameter, one value from a positional \
+ argument and one from a keyword argument.'),
}
class TypeChecker(BaseChecker):
@@ -202,13 +218,144 @@
self.add_message('W1111', node=node)
def visit_callfunc(self, node):
- """check that called method are infered to callable objects
+ """check that called functions/methods are inferred to callable
objects,
+ and that the arguments passed to the function match the parameters
in
+ the inferred function's definition
"""
+
+ # Build the set of keyword arguments, checking for duplicate
keywords,
+ # and count the positional arguments.
+ keyword_args = set()
+ num_positional_args = 0
+ for arg in node.args:
+ if isinstance(arg, astng.Keyword):
+ keyword = arg.arg
+ if keyword in keyword_args:
+ self.add_message('E1122', node=node, args=keyword)
+ keyword_args.add(keyword)
+ else:
+ num_positional_args += 1
+
called = safe_infer(node.func)
# only function, generator and object defining __call__ are allowed
if called is not None and not called.callable():
self.add_message('E1102', node=node,
args=node.func.as_string())
+ # Note that BoundMethod is a subclass of UnboundMethod (huh?), so
must
+ # come first in this 'if..else'.
+ if isinstance(called, astng.BoundMethod):
+ # Bound methods have an extra implicit 'self' argument.
+ num_positional_args += 1
+ elif isinstance(called, astng.UnboundMethod):
+ if called.decorators is not None:
+ for d in called.decorators.nodes:
+ if isinstance(d, astng.Name) and (d.name ==
'classmethod'):
+ # Class methods have an extra implicit 'cls'
argument.
+ num_positional_args += 1
+ break
+ elif (isinstance(called, astng.Function) or
+ isinstance(called, astng.Lambda)):
+ pass
+ else:
+ return
+
+ if called.args.args is None:
+ # Built-in functions have no argument information.
+ return
+
+ if len( called.argnames() ) != len( set( called.argnames() ) ):
+ # Duplicate parameter name (see E9801). We can't really make
sense
+ # of the function call in this case, so just return.
+ return
+
+ # Analyze the list of formal parameters.
+ num_mandatory_parameters = len(called.args.args) -
len(called.args.defaults)
+ parameters = []
+ parameter_name_to_index = {}
+ for i, arg in enumerate(called.args.args):
+ if isinstance(arg, astng.Tuple):
+ name = None
+ # Don't store any parameter names within the tuple, since
those
+ # are not assignable from keyword arguments.
+ else:
+ if isinstance(arg, astng.Keyword):
+ name = arg.arg
+ else:
+ assert isinstance(arg, astng.AssName)
+ # This occurs with:
+ # def f( (a), (b) ): pass
+ name = arg.name
+ parameter_name_to_index[name] = i
+ if i >= num_mandatory_parameters:
+ defval = called.args.defaults[i - num_mandatory_parameters]
+ else:
+ defval = None
+ parameters.append([(name, defval), False])
+
+ # Match the supplied arguments against the function parameters.
+
+ # 1. Match the positional arguments.
+ for i in range(num_positional_args):
+ if i < len(parameters):
+ parameters[i][1] = True
+ elif called.args.vararg is not None:
+ # The remaining positional arguments get assigned to the
*args
+ # parameter.
+ break
+ else:
+ # Too many positional arguments.
+ self.add_message('E1121', node=node)
+ break
+
+ # 2. Match the keyword arguments.
+ for keyword in keyword_args:
+ if keyword in parameter_name_to_index:
+ i = parameter_name_to_index[keyword]
+ if parameters[i][1]:
+ # Duplicate definition of function parameter.
+ self.add_message('E1124', node=node, args=keyword)
+ else:
+ parameters[i][1] = True
+ elif called.args.kwarg is not None:
+ # The keyword argument gets assigned to the **kwargs
parameter.
+ pass
+ else:
+ # Unexpected keyword argument.
+ self.add_message('E1123', node=node, args=keyword)
+
+ # 3. Match the *args, if any. Note that Python actually processes
+ # *args _before_ any keyword arguments, but we wait until after
+ # looking at the keyword arguments so as to make a more
conservative
+ # guess at how many values are in the *args sequence.
+ if node.starargs is not None:
+ for i in range(num_positional_args, len(parameters)):
+ [(name, defval), assigned] = parameters[i]
+ # Assume that *args provides just enough values for all
+ # non-default parameters after the last parameter assigned
by
+ # the positional arguments but before the first parameter
+ # assigned by the keyword arguments. This is the best we
can
+ # get without generating any false positives.
+ if (defval is not None) or assigned:
+ break
+ parameters[i][1] = True
+
+ # 4. Match the **kwargs, if any.
+ if node.kwargs is not None:
+ for i, [(name, defval), assigned] in enumerate(parameters):
+ # Assume that *kwargs provides values for all remaining
+ # unassigned named parameters.
+ if name is not None:
+ parameters[i][1] = True
+ else:
+ # **kwargs can't assign to tuples.
+ pass
+
+ # Check that any parameters without a default have been assigned
+ # values.
+ for [(name, defval), assigned] in parameters:
+ if (defval is None) and not assigned:
+ display_name = repr(name) if (name is not None) else
'<tuple>'
+ self.add_message('E1120', node=node, args=display_name)
def register(linter):
"""required method to auto register this checker """
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