master 685435cb52e: Eglot: simplify eglot--sig-info and fix edge cases (bug#62687)

[João Távora]

branch: master
commit 685435cb52eaa6f61b7088398f1f53e69d76e63e
Author: João Távora <joaotavora@gmail.com>
Commit: João Távora <joaotavora@gmail.com>

    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.
---
 lisp/progmodes/eglot.el | 40 ++++++++++++++++------------------------
 1 file changed, 16 insertions(+), 24 deletions(-)

diff --git a/lisp/progmodes/eglot.el b/lisp/progmodes/eglot.el
index 6134ab9150c..b10344a706b 100644
--- 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))