Merge pull request #52 from sobolevn/python38

Adds python3.8 support with AnnAssign and NamedExpr

.travis.yml

@@ -1,8 +1,10 @@
+dist: xenial
 language: python
 python:
   - '2.7'
   - '3.6'
   - '3.7'
+  - '3.8'
   - 'pypy'
   - 'pypy3'
 cache: pip

CHANGES.rst

@@ -3,10 +3,17 @@
 Changelog
 =========
 
-1.4.3 (unreleased)
+1.5.0 (unreleased)
 ------------------
 
-- Nothing changed yet.
+- Add ``python3.8`` support.
+  [sobolevn]
+
+- Add ``AnnAssign`` support.
+  [soboelvn]
+
+- Add ``NamedExpr`` or ``:=`` support.
+  [sobolevn]
 
 
 1.4.2 (2019-12-18)

flake8_builtins.py

@@ -35,6 +35,16 @@
     ]
     PY3 = False
 
+if sys.version_info >= (3, 6):
+    AnnAssign = ast.AnnAssign
+else:  # There was no `AnnAssign` before python3.6
+    AnnAssign = type('AnnAssign', (ast.AST, ), {})
+
+if sys.version_info >= (3, 8):
+    NamedExpr = ast.NamedExpr
+else:  # There was no walrus operator before python3.8
+    NamedExpr = type('NamedExpr', (ast.AST, ), {})
+
 
 class BuiltinsChecker(object):
     name = 'flake8_builtins'
@@ -76,9 +86,9 @@ def run(self):
             with_nodes.append(ast.AsyncWith)
         with_nodes = tuple(with_nodes)
 
+        value = None
         for statement in ast.walk(tree):
-            value = None
-            if isinstance(statement, ast.Assign):
+            if isinstance(statement, (ast.Assign, AnnAssign, NamedExpr)):
                 value = self.check_assignment(statement)
 
             elif isinstance(statement, function_nodes):
@@ -111,7 +121,11 @@ def check_assignment(self, statement):
         if type(statement.__flake8_builtins_parent) is ast.ClassDef:
             msg = self.class_attribute_msg
 
-        stack = list(statement.targets)
+        if isinstance(statement, ast.Assign):
+            stack = list(statement.targets)
+        else:  # This is `ast.AnnAssign` or `ast.NamedExpr`:
+            stack = [statement.target]
+
         while stack:
             item = stack.pop()
             if isinstance(item, (ast.Tuple, ast.List)):

run_tests.py

@@ -26,6 +26,26 @@ def test_builtin_top_level(self):
         ret = [c for c in checker.run()]
         self.assert_codes(ret, ['A001'])
 
+    @pytest.mark.skipif(
+        sys.version_info < (3, 6),
+        reason='AnnAssign appeared in 3.6',
+    )
+    def test_ann_assign(self):
+        tree = ast.parse('list: int = 1')
+        checker = BuiltinsChecker(tree, '/home/script.py')
+        ret = [c for c in checker.run()]
+        self.assert_codes(ret, ['A001'])
+
+    @pytest.mark.skipif(
+        sys.version_info < (3, 8),
+        reason='NamedExpr appeared in 3.8',
+    )
+    def test_walrus_operator(self):
+        tree = ast.parse('(dict := 1)')
+        checker = BuiltinsChecker(tree, '/home/script.py')
+        ret = [c for c in checker.run()]
+        self.assert_codes(ret, ['A001'])
+
     def test_nested(self):
         tree = ast.parse(
             'def bla():\n'

setup.py

@@ -31,6 +31,7 @@
         'Programming Language :: Python :: 3',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
+        'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: Implementation :: CPython',
         'Programming Language :: Python :: Implementation :: PyPy',
         'Topic :: Software Development',