Bug: eldoc error: (void-function nil) [9.3.7 (release_9.3.7-708-g5417e3 @ /home/n/.emacs.d/straight/build/org/)]

Bug: eldoc error: (void-function nil) [9.3.7 (release_9.3.7-708-g5417e3 @ /home/n/.emacs.d/straight/build/org/)]

[No Wayman]

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The patch to org-eldoc applied in b2b587387 still throws an error:

eldoc error: (void-function nil)

I was unable to step through this because (I think) eldoc causes 
the debugger to close as soon as input is received. The error 
occurs when `eldoc--invoke-strategy` attempts to funcall 
eldoc-documentation-default.

The attached patch works for me, but I do not know if it is the 
correct solution.

Emacs  : GNU Emacs 28.0.50 (build 1, x86_64-pc-linux-gnu, X 
toolkit, cairo version 1.17.3, Xaw3d scroll bars)
 of 2020-08-12
Package: Org mode version 9.3.7 (release_9.3.7-708-g5417e3 @ 
/home/n/.emacs.d/straight/build/org/)


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From 45dfdedbce47aa72c9f7f9f146b422236e9b9e23 Mon Sep 17 00:00:00 2001
From: Nicholas Vollmer <iarchivedmywholelife@gmail.com>
Date: Thu, 13 Aug 2020 14:20:05 -0400
Subject: [PATCH] org-eldoc: (org-eldoc-documentation-function): set
 `eldoc-documentation-functions'

* contrib/lisp/org-eldoc.el (org-eldoc-documentation-function):

b2b587387 did not set eldoc-documentation-functions, resulting in
`eldoc--invoke-strategy' throwing a void-fucntion error.
---
 contrib/lisp/org-eldoc.el | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/contrib/lisp/org-eldoc.el b/contrib/lisp/org-eldoc.el
index aa1dcb41b..ce0b7ddc2 100644
--- a/contrib/lisp/org-eldoc.el
+++ b/contrib/lisp/org-eldoc.el
@@ -138,7 +138,8 @@
              (string= lang "emacs-lisp")
              (string= lang "elisp")) (if (fboundp 'elisp-eldoc-documentation-function)
                                          (elisp-eldoc-documentation-function)
-                                       (let (eldoc-documentation-function)
+                                       (let ((eldoc-documentation-functions
+					      '(elisp-eldoc-var-docstring elisp-eldoc-funcall)))
                                          (eldoc-print-current-symbol-info))))
            ((or
              (string= lang "c") ;; http://github.com/nflath/c-eldoc
-- 
2.28.0

Re: Bug: eldoc error: (void-function nil) [9.3.7 (release_9.3.7-708-g5417e3 @ /home/n/.emacs.d/straight/build/org/)]

[Kyle Meyer]

No Wayman writes:

> The patch to org-eldoc applied in b2b587387 still throws an error:
>
> eldoc error: (void-function nil)
>
> I was unable to step through this because (I think) eldoc causes 
> the debugger to close as soon as input is received. The error 
> occurs when `eldoc--invoke-strategy` attempts to funcall 
> eldoc-documentation-default.
>
> The attached patch works for me, but I do not know if it is the 
> correct solution.

Yeah, b2b587387 dealt with the compiler warnings, but indeed it looks
like there is at least [*] this remaining issue.  Thanks for catching it
and for the patch.

I'm short on time tonight, but I'll take a closer look tomorrow.


[*] Perhaps org-eldoc-get-mode-local-documentation-function's use of
    eldoc-documentation-function is also problematic?

Re: Bug: eldoc error: (void-function nil) [9.3.7 (release_9.3.7-708-g5417e3 @ /home/n/.emacs.d/straight/build/org/)]

[Kyle Meyer]

No Wayman writes:

> Subject: [PATCH] org-eldoc: (org-eldoc-documentation-function): set
>  `eldoc-documentation-functions'
>
> * contrib/lisp/org-eldoc.el (org-eldoc-documentation-function):
>
> b2b587387 did not set eldoc-documentation-functions, resulting in
> `eldoc--invoke-strategy' throwing a void-fucntion error.

I'll plan to drop the unconventional blank line in the changelog entry
and s/fucntion/function/ when applying.

> ---
>  contrib/lisp/org-eldoc.el | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/contrib/lisp/org-eldoc.el b/contrib/lisp/org-eldoc.el
> index aa1dcb41b..ce0b7ddc2 100644
> --- a/contrib/lisp/org-eldoc.el
> +++ b/contrib/lisp/org-eldoc.el
> @@ -138,7 +138,8 @@
>               (string= lang "emacs-lisp")
>               (string= lang "elisp")) (if (fboundp 'elisp-eldoc-documentation-function)
>                                           (elisp-eldoc-documentation-function)
> -                                       (let (eldoc-documentation-function)
> +                                       (let ((eldoc-documentation-functions
> +					      '(elisp-eldoc-var-docstring elisp-eldoc-funcall)))
>                                           (eldoc-print-current-symbol-info))))
>             ((or
>               (string= lang "c") ;; http://github.com/nflath/c-eldoc

This works on my end testing with Emacs 26.3 and the Emacs master branch.
For example

   #+begin_src elisp
     (message "ok")
   #+end_src

shows "message: (FORMAT-STRING &rest ARGS)" when point is positioned
after "message".  I don't have Emacs 24 at hand, but the
eldoc-documentation-function let-binding you're dropping should be
retained for it, I think.  Assuming it's fine with you, I'll squash this
into your patch.

diff --git a/contrib/lisp/org-eldoc.el b/contrib/lisp/org-eldoc.el
index ce0b7ddc2..3b0999340 100644
--- a/contrib/lisp/org-eldoc.el
+++ b/contrib/lisp/org-eldoc.el
@@ -136,11 +136,16 @@ (defun org-eldoc-documentation-function (&rest _ignored)
    (let ((lang (org-eldoc-get-src-lang)))
      (cond ((or
              (string= lang "emacs-lisp")
-             (string= lang "elisp")) (if (fboundp 'elisp-eldoc-documentation-function)
-                                         (elisp-eldoc-documentation-function)
-                                       (let ((eldoc-documentation-functions
-					      '(elisp-eldoc-var-docstring elisp-eldoc-funcall)))
-                                         (eldoc-print-current-symbol-info))))
+             (string= lang "elisp"))
+	    (cond ((boundp 'eldoc-documentation-functions) ; Emacs>=28
+		   (let ((eldoc-documentation-functions
+			  '(elisp-eldoc-var-docstring elisp-eldoc-funcall)))
+		     (eldoc-print-current-symbol-info)))
+		  ((fboundp 'elisp-eldoc-documentation-function)
+		   (elisp-eldoc-documentation-function))
+		  (t  			; Emacs<25
+		   (let (eldoc-documentation-function)
+		     (eldoc-print-current-symbol-info)))))
            ((or
              (string= lang "c") ;; http://github.com/nflath/c-eldoc
              (string= lang "C")) (when (require 'c-eldoc nil t)

Re: Bug: eldoc error: (void-function nil) [9.3.7 (release_9.3.7-708-g5417e3 @ /home/n/.emacs.d/straight/build/org/)]

[No Wayman]

Kyle Meyer <kyle@kyleam.com> writes:

> Assuming it's fine with you, I'll squash this
> into your patch.

Fine by me

Re: Bug: eldoc error: (void-function nil) [9.3.7 (release_9.3.7-708-g5417e3 @ /home/n/.emacs.d/straight/build/org/)]

[Kyle Meyer]

No Wayman writes:

> Kyle Meyer <kyle@kyleam.com> writes:
>
>> Assuming it's fine with you, I'll squash this
>> into your patch.
>
> Fine by me

Applied (47f26b1e7).

Thanks.