SF patch #1056967, changes the semantics of Template.safe_substitute() to not

raise a ValueError for dangling delimiters (the delimiter itself is returned).

2 files changed, 10 insertions, 11 deletions

diff --git a/Lib/string.py b/Lib/string.py
index e10087e..7c0e001 100644
--- a/Lib/string.py
+++ b/Lib/string.py
@@ -199,7 +199,7 @@ class Template:
             if mo.group('escaped') is not None:
                 return self.delimiter
             if mo.group('invalid') is not None:
-                self._invalid(mo)
+                return self.delimiter
             raise ValueError('Unrecognized named group in pattern',
                              self.pattern)
         return self.pattern.sub(convert, self.template)
diff --git a/Lib/test/test_pep292.py b/Lib/test/test_pep292.py
index 19952e4..2a4353a 100644
--- a/Lib/test/test_pep292.py
+++ b/Lib/test/test_pep292.py
@@ -163,20 +163,19 @@ class TestTemplate(unittest.TestCase):
         raises(TypeError, s.safe_substitute, d, {})
 
     def test_delimiter_override(self):
+        eq = self.assertEqual
+        raises = self.assertRaises
         class AmpersandTemplate(Template):
             delimiter = '&'
         s = AmpersandTemplate('this &gift is for &{who} &&')
-        self.assertEqual(s.substitute(gift='bud', who='you'),
-                         'this bud is for you &')
-        self.assertRaises(KeyError, s.substitute)
-        self.assertEqual(s.safe_substitute(gift='bud', who='you'),
-                         'this bud is for you &')
-        self.assertEqual(s.safe_substitute(),
-                         'this &gift is for &{who} &')
+        eq(s.substitute(gift='bud', who='you'), 'this bud is for you &')
+        raises(KeyError, s.substitute)
+        eq(s.safe_substitute(gift='bud', who='you'), 'this bud is for you &')
+        eq(s.safe_substitute(), 'this &gift is for &{who} &')
         s = AmpersandTemplate('this &gift is for &{who} &')
-        self.assertRaises(ValueError, s.substitute,
-                          dict(gift='bud', who='you'))
-        self.assertRaises(ValueError, s.safe_substitute)
+        raises(ValueError, s.substitute, dict(gift='bud', who='you'))
+        eq(s.safe_substitute(), 'this &gift is for &{who} &')
+
 
 def test_main():
     from test import test_support