helpful-callable hangs on hippie-expand with smartparens required

[6AA4FD]

with helpful and smartparens loaded, emacs hangs after evaling (helpful-callable 'hippie-expand)
these logs are from emacs --version 27.0.50 -Q
the only other code run in the instance was adding melpa and installing the packages

i'm not too good at bug reports, so please tell me if i can help more

btrace.txt
profile.txt

EDIT: i realize that the profile file could be hard to read, so here's an image

[Wilfred]

I can't reproduce this on Emacs 26.1. Can you?

Looking at the backtrace, I wonder if find-function-advised-original is behaving differently in Emacs 27. What happens if you run the following?

M-x ielm
(find-function-advised-original 'hippie-expand)

Does it hang, or does it show output?

[6AA4FD]

it outputs (autoload "hippie-exp" 1203003 t nil) on 26 and something similar on 27
and (helpful-callable 'hippie-expand) also doesn't hang on 26
i want to mention that it's perfectly cool if you don't want to bother with supporting 27 yet, though i like your software and would obviously prefer it work better on my setup

[nickdrozd]

I can reproduce it. I can also work around it with the following sequence:

1. Run (helpful-callable 'hippie-expand). This will hang as described.
2. Run (describe-function 'hippie-expand). This will run successfully.
3. Run (helpful-callable 'hippie-expand) again. This time it will work.

I think this is because the builtin help functions do autoloading when needed, but Helpful doesn't. This seems to be the same underlying issue as #117.

[6AA4FD]

i get the same behaviour on my end

[Wilfred]

I think this is probably a duplicate of #117, which is now fixed :)

Let me know if not.

[hlissner]

This appears to still be a problem on Emacs 26.3. helpful-callable hangs indefinitely (or so it seems) on any function that has been autoloaded and advised. The issue goes away once the function has a concrete definition.

It can be reproduced with the following on vanilla Emacs:

(require 'helpful)
;; I've tested on functions and commands that exist as well
(autoload 'x "x" nil t)
(defun myadvice (orig-fn &rest args)
  (apply orig-fn args))
;; I've tried :after, :before, and :override with the same results
(advice-add 'x :around #'myadvice)
(helpful-callable 'x)

With debug-on-quit on, I've produced this backtrace after waiting a minute or so (I was experimenting on org-clock-in at the time):

Debugger entered--Lisp error: (quit)
  advice--p(#f(advice-wrapper :around nil myadvice))
  advice--cd*r(#f(advice-wrapper :around nil myadvice))
  find-function-advised-original(org-clock-in)
  find-function-library(org-clock-in)
  helpful--definition(org-clock-in t)
  helpful-update()
  helpful-callable(org-clock-in)
  (progn (require (quote helpful)) (autoload (quote org-clock-in) "org-clock" nil t) (defalias (quote myadvice) (function (lambda (orig-fn &rest args) (apply orig-fn args)))) (advice-add (quote org-clock-in) :around (function myadvice)) (setq debug-on-quit t) (helpful-callable (quote org-clock-in)))
  (unwind-protect (progn (require (quote helpful)) (autoload (quote org-clock-in) "org-clock" nil t) (defalias (quote myadvice) (function (lambda (orig-fn &rest args) (apply orig-fn args)))) (advice-add (quote org-clock-in) :around (function myadvice)) (setq debug-on-quit t) (helpful-callable (quote org-clock-in))) (delete-file "/tmp/doom-sandbox-TSLf3x"))
  eval-buffer(#<buffer  *load*> nil "/tmp/doom-sandbox-TSLf3x" nil t)  ; Reading at buffer position 20133
  load-with-code-conversion("/tmp/doom-sandbox-TSLf3x" "/tmp/doom-sandbox-TSLf3x" nil t)
  load("/tmp/doom-sandbox-TSLf3x" nil t)
  command-line-1(("-l" "/tmp/doom-sandbox-TSLf3x"))
  command-line()
  normal-top-level()

It appears to be trapped in advice--cd*r:

;; in nadvice.el.gz, L70
(defun advice--cd*r (f)
  (while (advice--p f)
    (setq f (advice--cdr f)))
  f)

I am on the latest commit of helpful: 982dd49

[hlissner]

Should I open a new issue for this?

[Wilfred]

Looks like #191 is the same issue, but thanks for the great repro!