Missing a base implementation of transform-expression for strings

* lisp/gnus/gnus-search.el (gnus-search-transform-expression):
  Othewise plain string searches would raise an error!

diff --git a/lisp/gnus/gnus-search.el b/lisp/gnus/gnus-search.el
index bc9aa9b808b88de9b4dfe80937fd08c8bbc907da..e8a7eee79ea6b1905e057f65324caec6549b773e 100644 (file)
--- a/lisp/gnus/gnus-search.el
+++ b/lisp/gnus/gnus-search.el
@@ -1086,6 +1086,11 @@ Responsible for handling and, or, and parenthetical expressions.")
     query)
    (mapconcat #'identity (reverse clauses) " ")))
 
+;; Most search engines just pass through plain strings.
+(cl-defmethod gnus-search-transform-expression ((_ gnus-search-engine)
+                                               (expr string))
+  expr)
+
 ;; Most search engines use implicit ANDs.
 (cl-defmethod gnus-search-transform-expression ((_ gnus-search-engine)
                                                (_expr (eql and)))