Fix support comprehensions inside functions when use strict_undefined…

Fixed regression caused by the fix for 🎫`320` where new logic added
to interpret list and dictionary comprehensions would fail for expression
oriented keys.  As the parsing in question was not necessary for these
keys, it's been removed.  Pull request courtesy Sébastien Granjoux.

Fixes: #398
Closes: #399
Pull-request: #399
Pull-request-sha: d708e27

Change-Id: Icc253e66b99ad30b3d2353e896c8345f4e94ad9a

doc/build/unreleased/398.rst

@@ -0,0 +1,8 @@
+.. change::
+    :tags: bug, parser
+    :tickets: 398
+
+    Fixed regression caused by the fix for :ticket:`320` where new logic added
+    to interpret list and dictionary comprehensions would fail for expression
+    oriented keys.  As the parsing in question was not necessary for these
+    keys, it's been removed.  Pull request courtesy Sébastien Granjoux.

mako/pyparser.py

@@ -92,8 +92,6 @@ def visit_FunctionDef(self, node):
 
     def visit_ListComp(self, node):
         if self.in_function:
-            if not isinstance(node.elt, _ast.Name):
-                self.visit(node.elt)
             for comp in node.generators:
                 self.visit(comp.iter)
         else:
@@ -103,8 +101,6 @@ def visit_ListComp(self, node):
 
     def visit_DictComp(self, node):
         if self.in_function:
-            if not isinstance(node.key, _ast.Name):
-                self.visit(node.elt)
             for comp in node.generators:
                 self.visit(comp.iter)
         else:

setup.cfg

@@ -89,7 +89,7 @@ show-source = true
 enable-extensions = G
 # E203 is due to https://github.com/PyCQA/pycodestyle/issues/373
 ignore =
-    A003,
+    A003,A005
     D,
     E203,E305,E711,E712,E721,E722,E741,
     N801,N802,N806,

test/test_template.py

@@ -878,6 +878,21 @@ def test_list_comprehensions_plus_undeclared_strict(self):
 
         eq_(result_lines(t.render(t="T")), ["t is: T", "a,b,c"])
 
+    def test_dict_comprehensions_in_function_plus_undeclared_strict(self):
+        t = Template(
+            """
+<%
+    def foo():
+        return {s[0]: s for s in ('foo',)}
+%>
+
+${ foo()['f'] }
+""",
+            strict_undefined=True,
+        )
+
+        eq_(result_lines(t.render()), ["foo"])
+
 
 class StopRenderingTest(TemplateTest):
     def test_return_in_template(self):