Avoid assigning an empty error message to delegated parse exception (#…

…534)
pyparsing · Feb 12, 2024 · f02e401 · f02e401
1 parent 2a1a8e8
commit f02e401
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/pyparsing/core.py b/pyparsing/core.py
@@ -4510,7 +4510,8 @@ def parseImpl(self, instring, loc, doActions=True):
             return self.expr._parse(instring, loc, doActions, callPreParse=False)
         except ParseBaseException as pbe:
             if not isinstance(self, Forward) or self.customName is not None:
-                pbe.msg = self.errmsg
+                if self.errmsg:
+                    pbe.msg = self.errmsg
             raise
 
     def leave_whitespace(self, recursive: bool = True) -> ParserElement: