Eglot: simplify eglot--sig-info and fix edge cases (bug#62687)

The documentation of each signature was rarely rendered because of
obsolete logic that skipped MarkupContent objects.

The new function follows the principle that echo are gets as little as
possible, while the *eldoc* buffer gets as much as possible (except,
for the individual parameter documentation, as I couldn't find a
single server that uses it).

Tested with clangd, pylsp, jdtls, gopls, rust-analyzer, zls.

* lisp/progmodes/eglot.el (eglot--sig-info): Simplify.

diff --git a/lisp/progmodes/eglot.el b/lisp/progmodes/eglot.el
index 6134ab9150ca242906bf22285df58d19df85d57c..b10344a706bf4ac6df6590ade800e5922f0594ae 100644 (file)
--- a/lisp/progmodes/eglot.el
+++ b/lisp/progmodes/eglot.el
@@ -3118,29 +3118,27 @@ for which LSP on-type-formatting should be requested."
   (mapconcat #'eglot--format-markup
              (if (vectorp contents) contents (list contents)) "\n"))
 
-(defun eglot--sig-info (sig &optional _activep sig-help-active-param)
+(defun eglot--sig-info (sig &optional sig-help-active-param briefp)
   (eglot--dbind ((SignatureInformation) label documentation parameters activeParameter)
       sig
     (with-temp-buffer
       (save-excursion (insert label))
       (let ((active-param (or activeParameter sig-help-active-param))
+            (labeldoc (and (not briefp) documentation
+                           (eglot--format-markup documentation)))
             params-start params-end)
         ;; Ad-hoc attempt to parse label as <name>(<params>)
         (when (looking-at "\\([^(]*\\)(\\([^)]+\\))")
           (setq params-start (match-beginning 2) params-end (match-end 2))
           (add-face-text-property (match-beginning 1) (match-end 1)
                                   'font-lock-function-name-face))
-        ;; Decide whether to add one-line-summary to signature line
-        (when (and (stringp documentation)
-                   (string-match "[[:space:]]*\\([^.\r\n]+[.]?\\)"
-                                 documentation))
-          (setq documentation (match-string 1 documentation))
-          (unless (string-prefix-p (string-trim documentation) label)
-            (goto-char (point-max))
-            (insert ": " (eglot--format-markup documentation))))
+        ;; Add documentation, indented so we can distinguish multiple signatures
+        (when labeldoc
+          (goto-char (point-max))
+          (insert "\n" (replace-regexp-in-string "^" "  " labeldoc)))
         ;; Decide what to do with the active parameter...
         (when (and active-param (< -1 active-param (length parameters)))
-          (eglot--dbind ((ParameterInformation) label documentation)
+          (eglot--dbind ((ParameterInformation) label)
               (aref parameters active-param)
             ;; ...perhaps highlight it in the formals list
             (when params-start
@@ -3157,17 +3155,7 @@ for which LSP on-type-formatting should be requested."
                 (if (and beg end)
                     (add-face-text-property
                      beg end
-                     'eldoc-highlight-function-argument))))
-            ;; ...and/or maybe add its doc on a line by its own.
-            (when documentation
-              (goto-char (point-max))
-              (insert "\n"
-                      (propertize
-                       (if (stringp label)
-                           label
-                         (apply #'buffer-substring (mapcar #'1+ label)))
-                       'face 'eldoc-highlight-function-argument)
-                      ": " (eglot--format-markup documentation))))))
+                     'eldoc-highlight-function-argument)))))))
       (buffer-string))))
 
 (defun eglot-signature-eldoc-function (cb)
@@ -3184,9 +3172,13 @@ for which LSP on-type-formatting should be requested."
            (let ((active-sig (and (cl-plusp (length signatures))
                                   (aref signatures (or activeSignature 0)))))
              (if (not active-sig) (funcall cb nil)
-               (funcall cb
-                        (mapconcat #'eglot--sig-info signatures "\n")
-                        :echo (eglot--sig-info active-sig t activeParameter))))))
+               (funcall
+                cb (mapconcat (lambda (s)
+                                (eglot--sig-info s (and (eq s active-sig)
+                                                        activeParameter)
+                                                 nil))
+                              signatures "\n")
+                :echo (eglot--sig-info active-sig activeParameter t))))))
        :deferred :textDocument/signatureHelp))
     t))