Add a Definition.is_definition function to be able to check if a name is a definition or not.

jedi/api/__init__.py

@@ -695,12 +695,15 @@ def names(source=None, path=None, encoding='utf-8', all_scopes=False,
     :param references: If True lists all the names that are not listed by
         ``definitions=True``. E.g. ``a = b`` returns ``b``.
     """
+    def def_ref_filter(_def):
+        is_def = _def.is_definition()
+        return definitions and is_def or references and not is_def
+
     # Set line/column to a random position, because they don't matter.
     script = Script(source, line=1, column=0, path=path, encoding=encoding)
     defs = [classes.Definition(script._evaluator, name_part)
-            for name_part in get_module_name_parts(script._parser.module())
-        if 390 < name_part.start_pos[0] < 399]
-    return sorted(defs, key=lambda x: (x.line, x.column))
+            for name_part in get_module_name_parts(script._parser.module())]
+    return sorted(filter(def_ref_filter, defs), key=lambda x: (x.line, x.column))
 
 
 def preload_module(*modules):

jedi/api/classes.py

@@ -699,6 +699,19 @@ class Definition(use_metaclass(CachedMetaClass, BaseDefinition)):
         iterable = list(iterable)
         return list(chain.from_iterable(iterable))
 
+    def is_definition(self):
+        """
+        Returns True, if defined as a name in a statement, function or class.
+        Returns False, if it's a reference to such a definition.
+        """
+        if not isinstance(self._definition, pr.NamePart):
+            # Currently only handle NameParts. Once we have a proper API, this
+            # will be the standard anyway.
+            raise NotImplementedError
+        stmt_or_imp = self._definition.get_parent_until((pr.ExprStmt, pr.Import))
+        exp_list = stmt_or_imp.expression_list()
+        return not exp_list or self._definition.start_pos < exp_list[0].start_pos
+
     def __eq__(self, other):
         return self._start_pos == other._start_pos \
             and self.module_path == other.module_path \

test/test_api/test_api_classes.py

@@ -200,8 +200,11 @@ class TestGotoAssignments(TestCase):
     function. They are not really different in functionality, but really
     different as an implementation.
     """
-    def test_basic(self):
-        refs = names('a = 1; a', references=True, definitions=False)
-        assert len(refs) == 1
-        ass = refs[0].goto_assignments()
-        assert ass[0].description == ''
+    def test_repetition(self):
+        defs = names('a = 1; a', references=True, definitions=False)
+        # Repeat on the same variable. Shouldn't change once we're on a
+        # definition.
+        for _ in range(3):
+            assert len(defs) == 1
+            ass = defs[0].goto_assignments()
+            assert ass[0].description == 'a = 1'