Fix a bug in the parser's future statement handling that led to "with"

not being recognized as a keyword after, e.g., this statement:
from __future__ import division, with_statement
 (backport from rev. 51993)

diff --git a/Lib/test/test_future.py b/Lib/test/test_future.py
index f5462e204d637c73541232226f89145c6f329871..f67c692115b4637a349640263b76286e827b798f 100644 (file)
--- a/Lib/test/test_future.py
+++ b/Lib/test/test_future.py
@@ -82,6 +82,23 @@ class FutureTest(unittest.TestCase):
         else:
             self.fail("expected exception didn't occur")
 
+    def test_parserhack(self):
+        # test that the parser.c::future_hack function works as expected
+        try:
+            exec "from __future__ import division, with_statement; with = 0"
+        except SyntaxError:
+            pass
+        else:
+            self.fail("syntax error didn't occur")
+
+        try:
+            exec "from __future__ import (with_statement, division); with = 0"
+        except SyntaxError:
+            pass
+        else:
+            self.fail("syntax error didn't occur")
+
+
 def test_main():
     test_support.run_unittest(FutureTest)
 

diff --git a/Misc/NEWS b/Misc/NEWS
index b6087a906f75736ee21441d5bbabc7468e787da0..e930453ade5384cf5b3b63ec99fb1f8fcdeb0773 100644 (file)
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,10 @@ What's New in Python 2.5.1c1?
 Core and builtins
 -----------------
 
+- Fix a bug in the parser's future statement handling that led to "with"
+  not being recognized as a keyword after, e.g., this statement:
+  from __future__ import division, with_statement
+
 - Allow exception instances to be directly sliced again.
 
 

diff --git a/Parser/parser.c b/Parser/parser.c
index 04d5817d6252f8ac50a030baf3ea1a9023b0b8f5..2ce84cd32b828e270e67e0ca9b1d25b283386cb3 100644 (file)
--- a/Parser/parser.c
+++ b/Parser/parser.c
@@ -181,7 +181,7 @@ static void
 future_hack(parser_state *ps)
 {
        node *n = ps->p_stack.s_top->s_parent;
-       node *ch;
+       node *ch, *cch;
        int i;
 
        /* from __future__ import ..., must have at least 4 children */
@@ -195,15 +195,17 @@ future_hack(parser_state *ps)
        if (NCH(ch) == 1 && STR(CHILD(ch, 0)) &&
            strcmp(STR(CHILD(ch, 0)), "__future__") != 0)
                return;
-       for (i = 3; i < NCH(n); i += 2) {
-               /* XXX: assume we don't have parentheses in import:
-                       from __future__ import (x, y, z)
-               */
-               ch = CHILD(n, i);
-               if (NCH(ch) == 1)
-                       ch = CHILD(ch, 0);
-               if (NCH(ch) >= 1 && TYPE(CHILD(ch, 0)) == NAME &&
-                   strcmp(STR(CHILD(ch, 0)), "with_statement") == 0) {
+       ch = CHILD(n, 3);
+       /* ch can be a star, a parenthesis or import_as_names */
+       if (TYPE(ch) == STAR)
+               return;
+       if (TYPE(ch) == LPAR)
+               ch = CHILD(n, 4);
+       
+       for (i = 0; i < NCH(ch); i += 2) {
+               cch = CHILD(ch, i);
+               if (NCH(cch) >= 1 && TYPE(CHILD(cch, 0)) == NAME &&
+                   strcmp(STR(CHILD(cch, 0)), "with_statement") == 0) {
                        ps->p_flags |= CO_FUTURE_WITH_STATEMENT;
                        break;
                }