Removed `ValueError` raising for string formatting message checkers if the string...

diff --git a/babel/messages/checkers.py b/babel/messages/checkers.py
index c07c5386abcd3cae374d2e4f0f1f42e92b9ce764..3a9c80fc191822a24adbc4e626d8ada2380ab531 100644 (file)
--- a/babel/messages/checkers.py
+++ b/babel/messages/checkers.py
@@ -70,7 +70,8 @@ def _validate_format(format, alternative):
     arguments are not interchangeable as `alternative` may contain less
     placeholders if `format` uses named placeholders.
 
-    If `format` does not use string formatting a `ValueError` is raised.
+    The behavior of this function is undefined if the string does not use
+    string formattings.
 
     If the string formatting of `alternative` is compatible to `format` the
     function returns `None`, otherwise a `TranslationError` is raised.
@@ -126,13 +127,6 @@ def _validate_format(format, alternative):
 
     a, b = map(_parse, (format, alternative))
 
-    # if a does not use string formattings, we are dealing with invalid
-    # input data.  This function only works if the first string provided
-    # does contain string format chars
-    if not a:
-        raise ValueError('original string provided does not use string '
-                         'formatting.')
-
     # now check if both strings are positional or named
     a_positional, b_positional = map(_check_positional, (a, b))
     if a_positional and not b_positional and not b: