re-allow Python values in ExprStatNode and NameNode in nogil sections if they...

re-allow Python values in ExprStatNode and NameNode in nogil sections if they do not need cleanup (e.g. cached builtin names or constants)

Cython/Compiler/ExprNodes.py

@@ -1431,7 +1431,7 @@ class NameNode(AtomicExprNode):
         if self.is_used_as_rvalue:
             entry = self.entry
             if entry.is_builtin:
-                # if not Options.cache_builtins: # cached builtins are ok
+                if not Options.cache_builtins: # cached builtins are ok
                     self.gil_error()
             elif entry.is_pyglobal:
                 self.gil_error()

Cython/Compiler/Nodes.py

@@ -3347,7 +3347,7 @@ class ExprStatNode(StatNode):
         self.expr.analyse_expressions(env)
 
     def nogil_check(self, env):
-        if self.expr.type.is_pyobject:
+        if self.expr.type.is_pyobject and self.expr.is_temp:
             self.gil_error()
 
     gil_message = "Discarding owned Python object"

tests/errors/nogil.pyx

@@ -82,8 +82,12 @@ def ticket_338():
         for obj from 0 <= obj < 4:
             pass
 
+def bare_pyvar_name(object x):
+    with nogil:
+        x
+
 # For m(), the important thing is that there are errors on all lines in the range 23-69
-# except these: 34, 44, 56, 58, 60, 62-64
+# except these: 29, 34, 44, 56, 58, 60, 62-64
 
 _ERRORS = u"""
 1:5: Function with Python return type cannot be declared nogil
@@ -96,8 +100,6 @@ _ERRORS = u"""
 26:12: Assignment of Python object not allowed without gil
 28:8: Discarding owned Python object not allowed without gil
 28:16: Constructing complex number not allowed without gil
-29:12: Accessing Python global or builtin not allowed without gil
-29:12: Discarding owned Python object not allowed without gil
 30:8: Backquote expression not allowed without gil
 30:8: Discarding owned Python object not allowed without gil
 30:9: Operation not allowed without gil