Issue 6089: str.format raises SystemError.

diff --git a/Lib/test/test_str.py b/Lib/test/test_str.py
index 51d2680adcd259e4d80cf8971a5ae57ccc4fcc83..5341af218da79b20460b98e82dccd08acf394176 100644 (file)
--- a/Lib/test/test_str.py
+++ b/Lib/test/test_str.py
@@ -351,6 +351,10 @@ class StrTest(
         self.assertRaises(IndexError, "{:s}".format)
         self.assertRaises(IndexError, "{}".format)
 
+        # issue 6089
+        self.assertRaises(ValueError, "{0[0]x}".format, [None])
+        self.assertRaises(ValueError, "{0[0](10)}".format, [None])
+
         # can't have a replacement on the field name portion
         self.assertRaises(TypeError, '{0[{1}]}'.format, 'abcdefg', 4)
 

diff --git a/Lib/test/test_unicode.py b/Lib/test/test_unicode.py
index 83bc5846af5aa1b87c19e5d4b03c917d82f30467..99155ec8df52f4b91ddb9b6d5029272ef00ceb05 100644 (file)
--- a/Lib/test/test_unicode.py
+++ b/Lib/test/test_unicode.py
@@ -1100,6 +1100,10 @@ class UnicodeTest(
         self.assertRaises(IndexError, u"{:s}".format)
         self.assertRaises(IndexError, u"{}".format)
 
+        # issue 6089
+        self.assertRaises(ValueError, u"{0[0]x}".format, [None])
+        self.assertRaises(ValueError, u"{0[0](10)}".format, [None])
+
         # can't have a replacement on the field name portion
         self.assertRaises(TypeError, u'{0[{1}]}'.format, u'abcdefg', 4)
 

diff --git a/Objects/stringlib/string_format.h b/Objects/stringlib/string_format.h
index ce7c90967bfe3d03b2846efc8683562208f90aef..ee6533e44b248d96c14a46c11d59b91513828ea0 100644 (file)
--- a/Objects/stringlib/string_format.h
+++ b/Objects/stringlib/string_format.h
@@ -375,8 +375,9 @@ FieldNameIterator_next(FieldNameIterator *self, int *is_attribute,
         *name_idx = get_integer(name);
         break;
     default:
-        /* interal error, can't get here */
-        assert(0);
+        /* Invalid character follows ']' */
+        PyErr_SetString(PyExc_ValueError, "Only '.' or '[' may "
+                        "follow ']' in format field specifier");
         return 0;
     }