Fix merging hover results (#2654)

Author: yyoncho

lsp-mode.el

@@ -1198,17 +1198,15 @@ the lists according to METHOD."
                                      (-compose #'not #'lsp-empty?)
                                      results)
                                (`(,hover) hover)
-                               (hovers (-reduce-from
-                                        (-lambda ((&Hover :contents) result)
-                                          (lsp:set-hover-contents
-                                           result (append
-                                                   (if (and (sequencep contents)
-                                                            (not (stringp contents)))
-                                                       contents
-                                                     (list contents))
-                                                   (lsp:hover-contents result))))
-                                        (lsp-make-hover)
-                                        hovers))))
+                               (hovers (lsp-make-hover
+                                        :contents
+                                        (-mapcat
+                                         (-lambda ((&Hover :contents))
+                                           (if (and (sequencep contents)
+                                                    (not (stringp contents)))
+                                               (append contents ())
+                                             (list contents)))
+                                         hovers)))))
        ("textDocument/completion"
         (lsp-make-completion-list
          :is-incomplete (seq-some

test/lsp-mode-test.el

@@ -165,5 +165,15 @@
     (should (lsp-point-in-range? (lsp-make-position :character 3 :line 3)
                                  range))))
 
+(ert-deftest lsp-test--merge-hover ()
+  (should (= (length (lsp:hover-contents
+                      (lsp--merge-results
+                       (list (lsp-make-hover :contents (vector "string"
+                                                               (lsp-make-marked-string :language "java"
+                                                                                       :value "XXX")))
+                             (lsp-make-hover :contents []))
+                       "textDocument/hover")))
+             2)))
+
 (provide 'lsp-mode-test)
 ;;; lsp-mode-test.el ends here