Re: eldoc recursion error

[James N. V. Cash <james.cash@occasionallycogent.com>]

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Kyle Meyer <kyle@kyleam.com> writes:
> Thanks for the patch!  For information about the expected commit message
> format, please see <https://orgmode.org/worg/org-contribute.html>.

Ah will do, thanks! I'm still learning how to work with the email &
patch-based workflow.

> Okay, so when eldoc-documentation-functions is defined (Emacs >=28), we
> take the first function and go with it.  That might not be exactly what
> you'd see in the native buffer, depending on whether there are other
> members of eldoc-documentation-functions and how they interact.  (I'm
> being vague, because I don't really know anything about eldoc, but it
> seems like that must be the case.)  Anyway, I'd guess it will be good
> enough in most cases, and it's certainly better than the recursion
> error.

Ah yes, very true. I've attached another patch, which tries to better
preserve how the new eldoc strategy works, by passing through the
callback to the mode-local eldoc function if available, which will be a
closure over the configured documentation strategy with
eldoc-documentation-functions bound to the appropriate mode-local value.


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From 4c2042c9e3820d88cd655cf01d572b9686a40d31 Mon Sep 17 00:00:00 2001
From: "James N. V. Cash" <james.nvc@gmail.com>
Date: Thu, 17 Sep 2020 10:51:13 -0400
Subject: [PATCH] Address org-eldoc-recursion issue

* org-eldoc.el (org-eldoc-get-mode-local-documentation-function,
org-eldoc-documentation-function): Support Emacs 28-style eldoc, where
instead of a single function, the eldoc-documentation-functions hook
has a list of functions, which may optionally take a callback.
---
 contrib/lisp/org-eldoc.el | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/contrib/lisp/org-eldoc.el b/contrib/lisp/org-eldoc.el
index 3b0999340..85e238e64 100644
--- a/contrib/lisp/org-eldoc.el
+++ b/contrib/lisp/org-eldoc.el
@@ -116,8 +116,13 @@
         (when (fboundp mode-func)
           (with-temp-buffer
             (funcall mode-func)
-            (setq doc-func (and eldoc-documentation-function
-                                (symbol-value 'eldoc-documentation-function)))
+	    (setq doc-func (if (boundp 'eldoc-documentation-functions)
+			       (lexical-let ((doc-funs (symbol-value 'eldoc-documentation-functions)))
+				 (lambda ()
+				   (let ((eldoc-documentation-functions doc-funs))
+				     (funcall eldoc-documentation-strategy))))
+			       (and eldoc-documentation-function
+				    (symbol-value 'eldoc-documentation-function))))
             (puthash lang doc-func org-eldoc-local-functions-cache))
           doc-func)
       cached-func)))
@@ -127,7 +132,7 @@
 (declare-function php-eldoc-function "php-eldoc" ())
 (declare-function go-eldoc--documentation-function "go-eldoc" ())
 
-(defun org-eldoc-documentation-function (&rest _ignored)
+(defun org-eldoc-documentation-function (&optional callback)
   "Return breadcrumbs when on a headline, args for src block header-line,
   calls other documentation functions depending on lang when inside src body."
   (or
@@ -161,7 +166,12 @@
              (string= lang "golang")) (when (require 'go-eldoc nil t)
                                         (go-eldoc--documentation-function)))
            (t (let ((doc-fun (org-eldoc-get-mode-local-documentation-function lang)))
-                (when (functionp doc-fun) (funcall doc-fun))))))))
+                (when (functionp doc-fun)
+		  (if (functionp callback)
+		      (condition-case nil
+			  (funcall doc-fun callback)
+			(wrong-number-of-arguments (funcall doc-fun)))
+		    (funcall doc-fun)))))))))
 
 ;;;###autoload
 (defun org-eldoc-load ()
-- 
2.25.1