bug#58029: 28.2; Struct boundaries ignored by bounds-of-thing-at-point

bug#58029: 28.2; Struct boundaries ignored by bounds-of-thing-at-point

[Richard Hopkins]

I think this is a bug - any thoughts on the following?

The initial "#s" as part of printed structures are ignored by
`bounds-of-thing-at-point' which means it will

a) pick up the wrong expression when inside the printed struct; and
b) ignore the struct even when point is on the initial "#"

The following `emacs -Q` recipe should help show the interaction
between the struct representation and whether it's picked up by
`bounds-of-thing-at-point'.

(require 'cl-lib)
(cl-defstruct foo a)
(make-foo :a 1)
;; => #s(foo 1)

;; Bounds should be found starting from 1, but is nil
(with-temp-buffer
   (insert (prin1-to-string (make-foo :a 1)))
   (goto-char (point-min))
   (list
    (buffer-string)
    (bounds-of-thing-at-point 'sexp)
    (prin1-to-string (read (current-buffer)))))
;; => ("#s(foo 1)" nil "#s(foo 1)")

;; Whilst there is a list from point, the boundary should be
;; adjusted backwards as it's part of a struct.
(with-temp-buffer
   (insert (prin1-to-string (make-foo :a 1)))
   (goto-char (point-min))
   (forward-char 2)
   (list
    (buffer-string)
    (bounds-of-thing-at-point 'sexp)
    (prin1-to-string (read (current-buffer)))))
;; => ("#s(foo 1)" (3 . 10) "(foo 1)")

In GNU Emacs 28.2 (build 1, x86_64-pc-cygwin)
  of 2022-09-15 built on fv-az140-985
Repository revision: 70134aa8264ded36d80248204b2ba43ae3d8f599
Repository branch: master
Windowing system distributor 'Microsoft Corp.', version 10.0.19044
Configured using:
  'configure
  
--srcdir=/cygdrive/d/a/scallywag/emacs/emacs-28.2-1.x86_64/src/emacs-28.2
  --prefix=/usr --exec-prefix=/usr --localstatedir=/var --sysconfdir=/etc
  --docdir=/usr/share/doc/emacs --htmldir=/usr/share/doc/emacs/html -C
  --with-w32 'CFLAGS=-ggdb -O2 -pipe -Wall -Werror=format-security
  -Wp,-D_FORTIFY_SOURCE=2 -fstack-protector-strong
  --param=ssp-buffer-size=4
  
-fdebug-prefix-map=/cygdrive/d/a/scallywag/emacs/emacs-28.2-1.x86_64/build=/usr/src/debug/emacs-28.2-1
  
-fdebug-prefix-map=/cygdrive/d/a/scallywag/emacs/emacs-28.2-1.x86_64/src/emacs-28.2=/usr/src/debug/emacs-28.2-1'
  CPPFLAGS= LDFLAGS='

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Important settings:
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Major mode: Lisp Interaction

Minor modes in effect:
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Load-path shadows:
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Memory information:
((conses 16 53485 7761)
  (symbols 48 6799 1)
  (strings 32 19933 2170)
  (string-bytes 1 623050)
  (vectors 16 13667)
  (vector-slots 8 177937 11466)
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  (buffers 992 11))

bug#58029: 28.2; Struct boundaries ignored by bounds-of-thing-at-point

[Lars Ingebrigtsen]

Richard Hopkins <emacs@unbit.co.uk> writes:

> The initial "#s" as part of printed structures are ignored by
> `bounds-of-thing-at-point' which means it will

I can reproduce this in Emacs 28.2, but not in Emacs 29, so it looks
like this has been fixed already.

bug#58029: 28.2; Struct boundaries ignored by bounds-of-thing-at-point

[Richard Hopkins]

On 2022-09-24 13:14, Lars Ingebrigtsen wrote:
> I can reproduce this in Emacs 28.2, but not in Emacs 29, so it looks
> like this has been fixed already.

Thanks for checking, however, I still get the same issue on what I
believe is Emacs 29...

$ src/emacs --version
GNU Emacs 29.0.50
Development version 1556b4376457 on master branch; build date 
2022-09-24.

As this also affects `backward-sexp' etc I was looking into a general
patch, but as it works for you I wonder if I'm running the wrong
version?

bug#58029: 28.2; Struct boundaries ignored by bounds-of-thing-at-point

[Lars Ingebrigtsen]

Richard Hopkins <emacs@unbit.co.uk> writes:

> Thanks for checking, however, I still get the same issue on what I
> believe is Emacs 29...

It only recognises these constructs if you're in a buffer where the
syntax rules say so.  So try:

(with-temp-buffer
  (insert (prin1-to-string (make-foo :a 1)))
  (emacs-lisp-mode)
  (goto-char (point-min))
  (list
   (buffer-string)
   (bounds-of-thing-at-point 'sexp)
   (prin1-to-string (read (current-buffer)))))

=> ("#s(foo 1)" (1 . 10) "#s(foo 1)")

bug#58029: 28.2; Struct boundaries ignored by bounds-of-thing-at-point

[Richard Hopkins]

On 2022-09-24 14:42, Lars Ingebrigtsen wrote:
> It only recognises these constructs if you're in a buffer where the
> syntax rules say so.  So try:
> 
> (with-temp-buffer
>   (insert (prin1-to-string (make-foo :a 1)))
>   (emacs-lisp-mode)
>   (goto-char (point-min))
>   (list
>    (buffer-string)
>    (bounds-of-thing-at-point 'sexp)
>    (prin1-to-string (read (current-buffer)))))
> 
> => ("#s(foo 1)" (1 . 10) "#s(foo 1)")

Ah, thanks for the pointer.  It works for me too (and `backward-sexp')
starting from Emacs 29 when the relevant mode is set, including the
scratch buffer with `lisp-interaction-mode'.

Please close, thanks.