Eglot: guard against empty 'textDocument/documentSymbol' response

* lisp/progmodes/eglot.el (eglot-imenu): Protect against missing response.

diff --git a/lisp/progmodes/eglot.el b/lisp/progmodes/eglot.el
index 24f2fda5ae5577afb75fddfd986de230c4aee1b3..7ad33fa37868e9c4397751438803b747742dc2e6 100644 (file)
--- a/lisp/progmodes/eglot.el
+++ b/lisp/progmodes/eglot.el
@@ -3295,10 +3295,11 @@ Returns a list as described in docstring of `imenu--index-alist'."
                               `(:textDocument
                                 ,(eglot--TextDocumentIdentifier))
                               :cancel-on-input non-essential))
-         (head (and res (elt res 0))))
-    (eglot--dcase head
-      (((SymbolInformation)) (eglot--imenu-SymbolInformation res))
-      (((DocumentSymbol)) (eglot--imenu-DocumentSymbol res)))))
+         (head (and (cl-plusp (length res)) (elt res 0))))
+    (when head
+      (eglot--dcase head
+        (((SymbolInformation)) (eglot--imenu-SymbolInformation res))
+        (((DocumentSymbol)) (eglot--imenu-DocumentSymbol res))))))
 
 (cl-defun eglot--apply-text-edits (edits &optional version)
   "Apply EDITS for current buffer if at VERSION, or if it's nil."