define-ibuffer-filter: Discard wrong filters

* lisp/ibuf-macs.el (define-ibuffer-filter): Do not store
in 'ibuffer-filtering-qualifiers' a wrong filter (Bug#25042).
* test/lisp/ibuffer-tests.el (ibuffer-test-Bug25042): Add test.

lisp/ibuf-macs.el

@@ -302,8 +302,13 @@ bound to the current value of the filter.
 			  qualifier))
 	 (ibuffer-update nil t))
        (push (list ',name ,description
-		   #'(lambda (buf qualifier)
-		       ,@body))
+		   (lambda (buf qualifier)
+                     (condition-case nil
+                         ,@body
+                       (error (ibuffer-pop-filter)
+                              (when (eq ',name 'predicate)
+                                (error "Wrong filter predicate: %S"
+                                       qualifier))))))
 	     ibuffer-filtering-alist)
        :autoload-end)))
 

test/lisp/ibuffer-tests.el

@@ -126,5 +126,17 @@
         (and (buffer-live-p it) (kill-buffer it))))))
 
 
+(ert-deftest ibuffer-test-Bug25042 ()
+  "Test for http://debbugs.gnu.org/25042 ."
+  (ibuffer)
+  (let ((filters ibuffer-filtering-qualifiers))
+    (unwind-protect
+        (progn
+          (ignore-errors ; Mistyped `match-string' instead of `string-match'.
+            (setq ibuffer-filtering-qualifiers nil)
+            (ibuffer-filter-by-predicate '(match-string "foo" (buffer-name))))
+          (should-not ibuffer-filtering-qualifiers))
+      (setq ibuffer-filtering-qualifiers filters))))
+
 (provide 'ibuffer-tests)
 ;; ibuffer-tests.el ends here