Differentiate between functions and methods

CHANGELOG.md

@@ -1,4 +1,8 @@
-# 1.5 (2020-05-24)
+# 1.6 (unreleased)
+
+* Differentiate between functions and methods (Jendrik Seipp, #112, #209).
+
+  # 1.5 (2020-05-24)
 
 * Support flake8 "noqa" error codes F401 (unused import) and F841 (unused
   local variable) (RJ722, #195).

README.md

@@ -154,7 +154,7 @@ results in the following output:
 
     dead_code.py:1: V104 unused import 'os' (90% confidence)
     dead_code.py:4: V103 unused function 'greet' (60% confidence)
-    dead_code.py:8: V106 unused variable 'message' (60% confidence)
+    dead_code.py:8: V107 unused variable 'message' (60% confidence)
 
 Vulture correctly reports "os" and "message" as unused, but it fails to
 detect that "greet" is actually used. The recommended method to deal
@@ -181,7 +181,7 @@ Passing both the original program and the whitelist to Vulture
 makes Vulture ignore the `greet` method:
 
     dead_code.py:1: V104 unused import 'os' (90% confidence)
-    dead_code.py:8: V106 unused variable 'message' (60% confidence)
+    dead_code.py:8: V107 unused variable 'message' (60% confidence)
 
 <!-- Hide noqa docs until we decide whether we want to support it.
 **Using "# noqa"**
@@ -208,7 +208,8 @@ codes.
 | V103        | Unused function   |
 | V104, F401  | Unused import     |
 | V105        | Unused property   |
-| V106, F841  | Unused variable   |
+| V106        | Unused method     |
+| V107, F841  | Unused variable   |
 | V201        | Unreachable code  |
 
 -->

TODO.md

@@ -15,10 +15,6 @@
 
 * Ignore hidden files and directories (might be unexpected, use
   --exclude instead).
-* Differentiate between functions and methods. For our purposes
-  methods are functions with a "self" parameter and they are stored as
-  attributes, not as variables. However, we can't differentiate
-  between function and method executions.
 * Use Assign instead of Name AST nodes for estimating the size of
   assignments (KISS).
 * Only count lines for unused code by storing a function `get_size` in

tests/test_noqa.py

@@ -80,9 +80,9 @@ def test_noqa_specific_issue_codes(v):
 
 @underground  # noqa: V102
 class Cellar:
-    @property  # noqa: V105
+    @property  # noqa: V106
     def wine(self):
-        grapes = True  # noqa: V106
+        grapes = True  # noqa: V107
 
     @without_ice  # noqa: V103
     def serve(self, quantity=50):
@@ -95,6 +95,7 @@ def serve(self, quantity=50):
     check(v.unused_classes, [])
     check(v.unused_funcs, [])
     check(v.unused_imports, [])
+    check(v.unused_methods, ["serve"])
     check(v.unused_props, [])
     check(v.unreachable_code, [])
     check(v.unused_vars, [])
@@ -104,7 +105,7 @@ def test_noqa_attributes(v):
     v.scan(
         """\
 something.x = 'x'  # noqa: V101
-something.z = 'z'  # noqa: V106 (code for unused variable)
+something.z = 'z'  # noqa: V107 (code for unused variable)
 something.u = 'u'  # noqa
 """
     )
@@ -191,15 +192,15 @@ def test_noqa_multiple_decorators(v):
         """\
 @bar  # noqa: V102
 class Foo:
-    @property  # noqa: V105
+    @property  # noqa: V106
     @make_it_cool
     @log
     def something(self):
         pass
 
     @coolify
     @property
-    def something_else(self):  # noqa: V105
+    def something_else(self):  # noqa: V106
         pass
 
     @a
@@ -235,10 +236,10 @@ def shave_sheep(sheep):
 def test_noqa_variables(v):
     v.scan(
         """\
-mitsi = "Mother"  # noqa: V106
+mitsi = "Mother"  # noqa: V107
 harry = "Father"  # noqa
 shero = "doggy"   # noqa: V101, V104 (code for unused import, attr)
-shinchan.friend = ['masao']  # noqa: V106 (code for unused variable)
+shinchan.friend = ['masao']  # noqa: V107 (code for unused variable)
 """
     )
     check(v.unused_vars, ["shero"])
@@ -254,7 +255,7 @@ def world(axis):  # noqa: V103, V201
 
 for _ in range(3):
     continue
-    xyz = hello(something, else):  # noqa: V201, V106
+    xyz = hello(something, else):  # noqa: V201, V107
 """
     )
     check(v.get_unused_code(), [])

tests/test_report.py

@@ -20,6 +20,9 @@ def bar(self):
     @property
     def myprop(self):
         pass
+
+def myfunc():
+    pass
 """
 
 
@@ -39,11 +42,12 @@ def test_item_report(check_report):
     expected = """\
 {filename}:1: unused import 'foo' (90% confidence)
 {filename}:3: unused class 'Foo' (60% confidence)
-{filename}:7: unused function 'bar' (60% confidence)
+{filename}:7: unused method 'bar' (60% confidence)
 {filename}:8: unused attribute 'foobar' (60% confidence)
 {filename}:9: unused variable 'foobar' (60% confidence)
 {filename}:11: unreachable code after 'return' (100% confidence)
 {filename}:13: unused property 'myprop' (60% confidence)
+{filename}:17: unused function 'myfunc' (60% confidence)
 """
     check_report(mock_code, expected)
 
@@ -52,10 +56,11 @@ def test_make_whitelist(check_report):
     expected = """\
 foo  # unused import ({filename}:1)
 Foo  # unused class ({filename}:3)
-bar  # unused function ({filename}:7)
+_.bar  # unused method ({filename}:7)
 _.foobar  # unused attribute ({filename}:8)
 foobar  # unused variable ({filename}:9)
 # unreachable code after 'return' ({filename}:11)
 _.myprop  # unused property ({filename}:13)
+myfunc  # unused function ({filename}:17)
 """
     check_report(mock_code, expected, make_whitelist=True)

tests/test_scavenging.py

@@ -95,9 +95,10 @@ async def bar(self):
 """
     )
     check(v.defined_classes, ["Foo"])
-    check(v.defined_funcs, ["bar"])
+    check(v.defined_funcs, [])
+    check(v.defined_methods, ["bar"])
     check(v.unused_classes, ["Foo"])
-    check(v.unused_funcs, ["bar"])
+    check(v.unused_methods, ["bar"])
 
 
 def test_function_and_method1(v):
@@ -114,9 +115,11 @@ def func():
 """
     )
     check(v.defined_classes, ["Bar"])
-    check(v.defined_funcs, ["func", "func"])
+    check(v.defined_funcs, ["func"])
+    check(v.defined_methods, ["func"])
     check(v.unused_classes, ["Bar"])
     check(v.unused_funcs, [])
+    check(v.unused_methods, ["func"])
 
 
 def test_attribute1(v):
@@ -162,7 +165,8 @@ def foo(self):
     )
     check(v.used_attrs, ["foo"])
     check(v.defined_classes, ["Bar"])
-    check(v.defined_funcs, ["foo"])
+    check(v.defined_funcs, [])
+    check(v.defined_methods, ["foo"])
     check(v.unused_classes, [])
     check(v.unused_funcs, [])
 
@@ -273,12 +277,22 @@ def __init__(self):
 class Bar(object):
     def foo(self):
         pass
+
+    @classmethod
+    def bar(cls):
+        pass
+
+    @staticmethod
+    def foobar():
+        pass
 """
     )
     check(v.defined_classes, ["Bar"])
-    check(v.defined_funcs, ["foo"])
+    check(v.defined_funcs, [])
+    check(v.defined_methods, ["foo", "bar", "foobar"])
     check(v.unused_classes, ["Bar"])
     check(v.unused_funcs, [])
+    check(v.unused_methods, ["bar", "foobar"])
 
 
 def test_token_types(v):

vulture/core.py

@@ -52,9 +52,10 @@
     "class": "V102",
     "function": "V103",
     "import": "V104",
-    "property": "V105",
+    "method": "V105",
+    "property": "V106",
+    "variable": "V107",
     "unreachable_code": "V201",
-    "variable": "V106",
 }
 
 
@@ -95,8 +96,12 @@ def _ignore_import(filename, import_name):
 
 
 def _ignore_function(filename, function_name):
-    return _is_special_name(function_name) or (
-        function_name.startswith("test_") and _is_test_file(filename)
+    return function_name.startswith("test_") and _is_test_file(filename)
+
+
+def _ignore_method(filename, method_name):
+    return _is_special_name(method_name) or (
+        method_name.startswith("test_") and _is_test_file(filename)
     )
 
 
@@ -171,7 +176,9 @@ def get_whitelist_string(self):
                 self.message, filename, self.first_lineno
             )
         else:
-            prefix = "_." if self.typ in ["attribute", "property"] else ""
+            prefix = ""
+            if self.typ in ["attribute", "method", "property"]:
+                prefix = "_."
             return "{}{}  # unused {} ({}:{:d})".format(
                 prefix, self.name, self.typ, filename, self.first_lineno
             )
@@ -207,6 +214,7 @@ def get_set(typ):
         self.defined_classes = get_list("class")
         self.defined_funcs = get_list("function")
         self.defined_imports = get_list("import")
+        self.defined_methods = get_list("method")
         self.defined_props = get_list("property")
         self.defined_vars = get_list("variable")
         self.unreachable_code = get_list("unreachable_code")
@@ -312,6 +320,7 @@ def by_size(item):
             + self.unused_classes
             + self.unused_funcs
             + self.unused_imports
+            + self.unused_methods
             + self.unused_props
             + self.unused_vars
             + self.unreachable_code
@@ -360,6 +369,10 @@ def unused_imports(self):
             self.defined_imports, self.used_names | self.used_attrs
         )
 
+    @property
+    def unused_methods(self):
+        return _get_unused_items(self.defined_methods, self.used_attrs)
+
     @property
     def unused_props(self):
         return _get_unused_items(self.defined_props, self.used_attrs)
@@ -557,7 +570,26 @@ def visit_FunctionDef(self, node):
             utils.get_decorator_name(decorator)
             for decorator in node.decorator_list
         ]
-        typ = "property" if "@property" in decorator_names else "function"
+
+        first_arg = None
+        if node.args.args:
+            try:
+                first_arg = node.args.args[0].arg
+            except AttributeError:
+                # Python 2.7
+                first_arg = node.args.args[0].id
+
+        if "@property" in decorator_names:
+            typ = "property"
+        elif (
+            "@staticmethod" in decorator_names
+            or "@classmethod" in decorator_names
+            or first_arg == "self"
+        ):
+            typ = "method"
+        else:
+            typ = "function"
+
         if any(
             _match(name, self.ignore_decorators) for name in decorator_names
         ):
@@ -568,8 +600,11 @@ def visit_FunctionDef(self, node):
             )
         elif typ == "property":
             self._define(self.defined_props, node.name, node)
+        elif typ == "method":
+            self._define(
+                self.defined_methods, node.name, node, ignore=_ignore_method
+            )
         else:
-            # Function is not a property.
             self._define(
                 self.defined_funcs, node.name, node, ignore=_ignore_function
             )

vulture/noqa.py

@@ -42,7 +42,7 @@
     # flake8 F401: module imported but unused.
     "F401": "V104",
     # flake8 F841: local variable is assigned to but never used.
-    "F841": "V106",
+    "F841": "V107",
 }