Option to force leading whitespace

chatcommands.py

@@ -358,8 +358,10 @@ def do_blacklist(blacklist_type, msg, force=False):
     append_force_to_do = "; append `-force` if you really want to do that."
 
     pattern = get_pattern_from_content_source(msg)
-    # Remove any leading whitespaces
-    pattern = regex.sub(r"^\s*", "", pattern)
+
+    has_leading_whitespace = ""
+    if regex.search(r"^\s*", "", pattern):
+        has_leading_whitespace = "The regex contains a leading whitespace character."
     has_u202d = ""
     if '\u202d' in pattern:
         has_u202d = (
@@ -398,12 +400,17 @@ def do_blacklist(blacklist_type, msg, force=False):
                 concretized_pattern, is_username=username, is_watchlist=is_watchlist, is_phone=is_phone)
 
             if reasons:
+                has_leading_whitespace = "; in addition, " + has_leading_whitespace.lower() \
+                                         if has_leading_whitespace else ""
                 has_u202d = "; in addition, " + has_u202d.lower() if has_u202d else ""
                 has_unescaped_dot = "; in addition, " + has_unescaped_dot.lower() if has_unescaped_dot else ""
                 raise CmdException(
                     "That pattern looks like it's already caught by " +
                     format_blacklist_reasons(reasons) + has_unescaped_dot + has_u202d + append_force_to_do)
 
+        if has_leading_whitespace:
+            raise CmdException(has_leading_whitespace + append_force_to_do)
+
         if has_u202d:
             raise CmdException(has_u202d + has_unescaped_dot + append_force_to_do)