Remove the dependency on sourcecodegen.

We do not need to convert the ast to source code before passing it to the
RestrictedPython machinery. It takes the result of the 2.7 ast.parse() as well.

requirements-full.txt

@@ -31,7 +31,6 @@ pbr==3.0.0
 persistent==4.2.2
 pytz==2017.2
 six==1.10.0
-sourcecodegen==0.6.14
 transaction==2.1.2
 waitress==1.0.2
 z3c.pt==3.0

setup.py

@@ -63,7 +63,6 @@ def _read_file(filename):
         'ZODB',
         'setuptools',
         'six',
-        'sourcecodegen',
         'transaction',
         'waitress',
         'zExceptions >= 3.4',

src/Products/PageTemplates/expression.py

@@ -1,6 +1,5 @@
-from ast import NodeTransformer
+from ast import NodeTransformer, parse
 from types import ClassType
-from compiler import parse as ast24_parse
 
 from OFS.interfaces import ITraversable
 from zExceptions import NotFound, Unauthorized
@@ -23,7 +22,6 @@
 from chameleon.astutil import Symbol
 from chameleon.astutil import Static
 from chameleon.codegen import template
-from sourcecodegen import generate_code
 
 from z3c.pt import expressions
 import collections
@@ -170,13 +168,10 @@ def rewrite(self, node):
 
     def parse(self, string):
         encoded = string.encode('utf-8')
-        node = ast24_parse(encoded, 'eval').node
+        node = parse(encoded, mode='eval')
         MutatingWalker.walk(node, self.rm)
-        string = generate_code(node)
-        decoded = string.decode('utf-8')
-        value = super(UntrustedPythonExpr, self).parse(decoded)
 
         # Run restricted python transform
-        self.rt.visit(value)
+        self.rt.visit(node)
 
-        return value
+        return node

versions-prod.cfg

@@ -27,7 +27,6 @@ pytz = 2017.2
 Record = 3.2
 RestrictedPython = 3.6.0
 six = 1.10.0
-sourcecodegen = 0.6.14
 transaction = 2.1.2
 waitress = 1.0.2
 WebOb = 1.7.2