Fixed issue: custom help messages in ValidationError using several variables were not rendering to string correctly and instead were displaying Error while formatting the help message. Fixes #58

Author: Sylvain MARIE

valid8/base.py

@@ -223,7 +223,8 @@ def get_help_msg(self):
             # first format if needed
             try:
                 is_context_a_copy = False
-                variables = re.findall("{\\S+}", help_msg)
+                # note: use question mark so as to be non-greedy
+                variables = re.findall("{\\S+?}", help_msg)
                 for var_name_ in set(variables):
                     # extract the variable name
                     var_name_ = var_name_[1:-1]

valid8/tests/issues/test_issue_58.py

@@ -0,0 +1,17 @@
+import pytest
+
+from valid8 import ValidationError, validate
+
+
+def test_err_msg_formatting():
+    """Test for https://github.com/smarie/python-valid8/issues/58"""
+
+    class CustomError(ValidationError):
+        help_msg = "{a}='{b}': hello"
+
+    with pytest.raises(CustomError) as err:
+        validate('dummy', False, equals=True, error_type=CustomError, a=0, b=1)
+
+    assert str(err.value) == "0='1': hello. Error validating [dummy=False]. " \
+                             "NotEqual: x == True does not hold for x=False. " \
+                             "Wrong value: False."