16123 FIX Use the original message text for rewriting the comment field

Werk 16534 made the rewriting of the comment field use the comment field
itself as the basis. For this field, it doesn't really make sense, because
rewriting is the only way to fill that field, so e.g. \0 was always empty.

With this change, we revert to the old behaviour where all match groups
refer to the original message text.

Change-Id: I761db0445b485da62c30656b42bcc65ed30d1151

.werks/16123.md

@@ -0,0 +1,19 @@
+[//]: # (werk v2)
+# Use the original message text for rewriting the comment field
+
+key        | value
+---------- | ---
+date       | 2024-09-11T13:54:07+00:00
+version    | 2.3.0p17
+class      | fix
+edition    | cre
+component  | ec
+level      | 1
+compatible | yes
+
+Werk 16534 made the rewriting of the comment field use the comment field
+itself as the basis. For this field, it doesn't really make sense, because
+rewriting is the only way to fill that field, so e.g. \0 was always empty.
+
+With this change, we revert to the old behaviour where all match groups
+refer to the original message text.

cmk/ec/main.py

@@ -1465,9 +1465,7 @@ def rewrite_event(  # pylint: disable=too-many-branches
             event["first"] = event["time"]
         event["last"] = event["time"]
         if "set_comment" in rule:
-            event["comment"] = replace_groups(
-                rule["set_comment"], event.get("comment", ""), match_groups
-            )
+            event["comment"] = replace_groups(rule["set_comment"], event["text"], match_groups)
         if "set_text" in rule:
             event["text"] = replace_groups(rule["set_text"], event["text"], match_groups)
         if "set_host" in rule:

cmk/gui/mkeventd/wato.py

@@ -1354,7 +1354,7 @@ def vs_mkeventd_rule(customer: str | None = None) -> Dictionary:
                     "etc. matching group."
                 )
                 + _(
-                    "The placeholder <tt>\\0</tt> will be replaced by the original text of this field. "
+                    "The placeholder <tt>\\0</tt> will be replaced by the original message text. "
                     "This allows you to add new information at the beginning or at the end."
                 ),
                 size=64,