Update docs for re_unescape

diff --git a/tornado/util.py b/tornado/util.py
index 71f13611b934a0587dcbcf8f8320dbd3ca1e55e4..4283d4e86aa11388bccef436e57239d297c452ed 100644 (file)
--- a/tornado/util.py
+++ b/tornado/util.py
@@ -181,6 +181,7 @@ def errno_from_exception(e):
 _alphanum = frozenset(
     "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")
 
+
 def _re_unescape_replacement(match):
     group = match.group(1)
     if group[0] in _alphanum:
@@ -189,10 +190,16 @@ def _re_unescape_replacement(match):
 
 _re_unescape_pattern = re.compile(r'\\(.)', re.DOTALL)
 
+
 def re_unescape(s):
-    '''
-    unescape a string escaped by ``re.escape()``
-    '''
+    """Unescape a string escaped by `re.escape`.
+
+    May raise ``ValueError`` for regular expressions which could not
+    have been produced by `re.escape` (for example, strings containing
+    ``\d`` cannot be unescaped).
+
+    .. versionadded:: 4.4
+    """
     return _re_unescape_pattern.sub(_re_unescape_replacement, s)
 
 

diff --git a/tornado/web.py b/tornado/web.py
index 1226f448cc38c62efccd42ac1466552cbcbe9ad2..8826c62b0dab6aa6381f44c06c0e02ca9df5d043 100644 (file)
--- a/tornado/web.py
+++ b/tornado/web.py
@@ -3032,7 +3032,7 @@ class URLSpec(object):
                     unescaped_fragment = re_unescape(fragment)
                 except ValueError as exc:
                     raise ValueError(exc.args[0] + '; invalid url: %r' % pattern)
-                pieces.append(re_unescape(fragment))
+                pieces.append(unescaped_fragment)
 
         return (''.join(pieces), self.regex.groups)