Corrected a formerly obscure bug in the compiler module; Python Scripts

revealed it.  "print" with output to a stream and a trailing comma needs to
end with a POP_TOP instruction.

compiler/pycodegen.py

@@ -795,7 +795,7 @@ def visitCallFunc(self, node):
         opcode = callfunc_opcode_info[have_star, have_dstar]
         self.emit(opcode, kw << 8 | pos)
 
-    def visitPrint(self, node):
+    def visitPrint(self, node, newline=0):
         self.set_lineno(node)
         if node.dest:
             self.visit(node.dest)
@@ -806,11 +806,13 @@ def visitPrint(self, node):
             if node.dest:
                 self.emit('ROT_TWO')
                 self.emit('PRINT_ITEM_TO')
+                if not newline:
+                    self.emit('POP_TOP')
             else:
                 self.emit('PRINT_ITEM')
 
     def visitPrintnl(self, node):
-        self.visitPrint(node)
+        self.visitPrint(node, 1)
         if node.dest:
             self.emit('PRINT_NEWLINE_TO')
         else:

tests/restricted_module.py

@@ -13,6 +13,15 @@ def print2():
     print >>x, 'Hello, world!',
     return printed
 
+def printLines():
+    # This failed before Zope 2.4.0a2
+    r = range(3)
+    for n in r:
+        for m in r:
+            print m + n * len(r),
+        print
+    return printed
+
 def primes():
     # Somewhat obfuscated code on purpose
     print filter(None,map(lambda y:y*reduce(lambda x,y:x*y!=0,

tests/testRestrictions.py

@@ -169,6 +169,10 @@ def checkPrint(self):
             res = self.execFunc('print%s' % i)
             assert res == 'Hello, world!', res
 
+    def checkPrintLines(self):
+        res = self.execFunc('printLines')
+        assert res == '0 1 2\n3 4 5\n6 7 8\n', res
+
     def checkPrimes(self):
         res = self.execFunc('primes')
         assert res == '[2, 3, 5, 7, 11, 13, 17, 19]', res