Support Python 3.5 async/await statements for Pyflakes.

Author: playpauseandstop

pyflakes/checker.py

@@ -649,8 +649,9 @@ def ignore(self, node):
         pass
 
     # "stmt" type nodes
-    DELETE = PRINT = FOR = WHILE = IF = WITH = WITHITEM = RAISE = \
-        TRYFINALLY = ASSERT = EXEC = EXPR = ASSIGN = handleChildren
+    DELETE = PRINT = FOR = ASYNCFOR = WHILE = IF = WITH = WITHITEM = \
+        ASYNCWITH = ASYNCWITHITEM = RAISE = TRYFINALLY = ASSERT = EXEC = \
+        EXPR = ASSIGN = handleChildren
 
     CONTINUE = BREAK = PASS = ignore
 
@@ -752,7 +753,7 @@ def YIELD(self, node):
         self.scope.isGenerator = True
         self.handleNode(node.value, node)
 
-    YIELDFROM = YIELD
+    AWAIT = YIELDFROM = YIELD
 
     def FUNCTIONDEF(self, node):
         for deco in node.decorator_list:
@@ -762,6 +763,8 @@ def FUNCTIONDEF(self, node):
         if self.withDoctest:
             self.deferFunction(lambda: self.handleDoctests(node))
 
+    ASYNCFUNCTIONDEF = FUNCTIONDEF
+
     def LAMBDA(self, node):
         args = []
         annotations = []

pyflakes/test/test_other.py

@@ -988,3 +988,55 @@ def bar():
     def test_returnOnly(self):
         """Do not crash on lone "return"."""
         self.flakes('return 2')
+
+
+class TestAsyncStatements(TestCase):
+
+    @skipIf(version_info < (3, 5), 'new in Python 3.5')
+    def test_asyncDef(self):
+        self.flakes('''
+        async def bar():
+            return 42
+        ''')
+
+    @skipIf(version_info < (3, 5), 'new in Python 3.5')
+    def test_asyncDefAwait(self):
+        self.flakes('''
+        async def read_data(db):
+            await db.fetch('SELECT ...')
+        ''')
+
+    @skipIf(version_info < (3, 5), 'new in Python 3.5')
+    def test_asyncDefUndefined(self):
+        self.flakes('''
+        async def bar():
+            return foo()
+        ''', m.UndefinedName)
+
+    @skipIf(version_info < (3, 5), 'new in Python 3.5')
+    def test_asyncFor(self):
+        self.flakes('''
+        async def read_data(db):
+            output = []
+            async for row in db.cursor():
+                output.append(row)
+            return output
+        ''')
+
+    @skipIf(version_info < (3, 5), 'new in Python 3.5')
+    def test_asyncWith(self):
+        self.flakes('''
+        async def commit(session, data):
+            async with session.transaction():
+                await session.update(data)
+        ''')
+
+    @skipIf(version_info < (3, 5), 'new in Python 3.5')
+    def test_asyncWithItem(self):
+        self.flakes('''
+        async def commit(session, data):
+            async with session.transaction() as trans:
+                await trans.begin()
+                ...
+                await trans.end()
+        ''')