SF patch #1056967, changes the semantics of Template.safe_substitute() to not
raise a ValueError for dangling delimiters (the delimiter itself is returned).
diff --git a/Doc/lib/libstring.tex b/Doc/lib/libstring.tex
index c9d27b5..1828b2e 100644
--- a/Doc/lib/libstring.tex
+++ b/Doc/lib/libstring.tex
@@ -131,8 +131,16 @@
Like \method{substitute()}, except that if placeholders are missing from
\var{mapping} and \var{kws}, instead of raising a \exception{KeyError}
exception, the original placeholder will appear in the resulting string
-intact. Note that other exceptions may still be raised, including
-\exception{ValueError} as described above.
+intact. Also, unlike with \method{substitute()}, any other appearances of the
+\samp{\$} will simply return \samp{\$} instead of raising
+\exception{ValueError}.
+
+While other exceptions may still occur, this method is called ``safe'' because
+substitutions always tries to return a usable string instead of raising an
+exception. In another sense, \method{safe_substitute()} may be anything other
+than safe, since it will silently ignore malformed templates containing
+dangling delimiters, unmatched braces, or placeholders that are not valid
+Python identifiers.
\end{methoddesc}
\class{Template} instances also provide one public data attribute:
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 @@
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 @@
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
diff --git a/Misc/NEWS b/Misc/NEWS
index 001152a..a75dff1 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -56,6 +56,10 @@
Library
-------
+- Patch #1056967 changes the semantics of Template.safe_substitute() so that
+ no ValueError is raised on an 'invalid' match group. Now the delimiter is
+ returned.
+
- Bug #1052503 pdb.runcall() was not passing along keyword arguments.
- Bug #902037: XML.sax.saxutils.prepare_input_source() now combines relative