Bug: org-string-display throws on image display property [9.1.9 (release_9.1.9-65-g5e4542 @ /home/blc/.local/share/emacs/27.0.50/lisp/org/)]

Bug: org-string-display throws on image display property [9.1.9 (release_9.1.9-65-g5e4542 @ /home/blc/.local/share/emacs/27.0.50/lisp/org/)]

[Basil L. Contovounesios]

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Severity: minor

0. emacs -Q
1. M-x toggle-debug-on-error RET
2. Evaluate the following:

  (require 'org)
  (org-string-display
   (propertize " " 'display '(image :type svg
                                    :file "/path/to/image.svg")))

This gives the following error backtrace:


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Debugger entered--Lisp error: (wrong-type-argument sequencep t)
  #f(compiled-function (s property filter) #<bytecode 0x394179>)(t invisible #f(compiled-function (props) #<bytecode 0x394185>))
  #f(compiled-function (s) #<bytecode 0x11718f5>)(t)
  #f(compiled-function (props) #<bytecode 0x1171905>)((display (image :type svg :file "/path/to/image.svg")))
  #f(compiled-function (s property filter) #<bytecode 0x394179>)(#(" " 0 1 (display (image :type svg :file "/path/to/image.svg"))) display #f(compiled-function (props) #<bytecode 0x1171905>))
  #f(compiled-function (build-from-parts prune-invisible s) #<bytecode 0x3940dd>)(#f(compiled-function (s property filter) #<bytecode 0x394179>) #f(compiled-function (s) #<bytecode 0x11718f5>) #(" " 0 1 (display (image :type svg :file "/path/to/image.svg"))))
  org-string-display(#(" " 0 1 (display (image :type svg :file "/path/to/image.svg"))))
  eval((org-string-display (propertize " " 'display '(image :type svg :file "/path/to/image.svg"))) nil)
  elisp--eval-last-sexp(t)
  eval-last-sexp(t)
  eval-print-last-sexp(nil)
  funcall-interactively(eval-print-last-sexp nil)
  call-interactively(eval-print-last-sexp nil nil)
  command-execute(eval-print-last-sexp)

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I realise that org-string-display is a relatively obscure function that
was probably not designed with image or other complex display properties
in mind, but AFAICT the following is a pretty obvious "fix", given that
the surrounding code expects 'value' to be a string or nil, but never t:


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diff --git a/lisp/org/org-macs.el b/lisp/org/org-macs.el
index 583633605f..5ab069e6a2 100644
--- a/lisp/org/org-macs.el
+++ b/lisp/org/org-macs.el
@@ -108,7 +108,7 @@ org-string-display
 		       ;; string (face...).
 		       (let* ((display (plist-get props 'display))
 			      (value (if (stringp display) display
-				       (cl-some #'stringp display))))
+                                       (cl-find-if #'stringp display))))
 			 (when value
 			   (apply #'propertize
 				  ;; Displayed string could contain

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With this change, the return value of org-string-display does not really
make sense for images, but at least the function doesn't barf on complex
but valid display properties.  WDYT?

Thanks,

-- 
Basil

Emacs  : GNU Emacs 27.0.50 (build 3, x86_64-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2018-09-01
Package: Org mode version 9.1.9 (release_9.1.9-65-g5e4542 @ /home/blc/.local/share/emacs/27.0.50/lisp/org/)

Re: Bug: org-string-display throws on image display property [9.1.9 (release_9.1.9-65-g5e4542 @ /home/blc/.local/share/emacs/27.0.50/lisp/org/)]

[Nicolas Goaziou]

Hello,

"Basil L. Contovounesios" <contovob@tcd.ie> writes:

> Severity: minor
>
> 0. emacs -Q
> 1. M-x toggle-debug-on-error RET
> 2. Evaluate the following:
>
>   (require 'org)
>   (org-string-display
>    (propertize " " 'display '(image :type svg
>                                     :file "/path/to/image.svg")))
>
> This gives the following error backtrace:
>
> Debugger entered--Lisp error: (wrong-type-argument sequencep t)

`org-string-display' doesn't exist anymore in master (Org 9.2). However,
there is the same error with `org-string-width'. 

What is `org-string-width' supposed to do on your example? Probably
return an error.

> I realise that org-string-display is a relatively obscure function that
> was probably not designed with image or other complex display properties
> in mind, but AFAICT the following is a pretty obvious "fix", given that
> the surrounding code expects 'value' to be a string or nil, but never t:
>
> diff --git a/lisp/org/org-macs.el b/lisp/org/org-macs.el
> index 583633605f..5ab069e6a2 100644
> --- a/lisp/org/org-macs.el
> +++ b/lisp/org/org-macs.el
> @@ -108,7 +108,7 @@ org-string-display
>  		       ;; string (face...).
>  		       (let* ((display (plist-get props 'display))
>  			      (value (if (stringp display) display
> -				       (cl-some #'stringp display))))
> +                                       (cl-find-if #'stringp display))))
>  			 (when value
>  			   (apply #'propertize
>  				  ;; Displayed string could contain
>
>
> With this change, the return value of org-string-display does not really
> make sense for images, but at least the function doesn't barf on complex
> but valid display properties.  WDYT?

If `org-string-width' returns nil, it will ensue an error somewhere
further in the code. So returning an error right here is better (or
find a way to compute the width of an image in columns).

As another data point, `string-width' returns 1 on your example, which
is probably wrong.

WDYT?

Regards,

-- 
Nicolas Goaziou

Re: Bug: org-string-display throws on image display property [9.1.9 (release_9.1.9-65-g5e4542 @ /home/blc/.local/share/emacs/27.0.50/lisp/org/)]

[Basil L. Contovounesios]

Nicolas Goaziou <mail@nicolasgoaziou.fr> writes:

> "Basil L. Contovounesios" <contovob@tcd.ie> writes:
>
>> Severity: minor
>>
>> 0. emacs -Q
>> 1. M-x toggle-debug-on-error RET
>> 2. Evaluate the following:
>>
>>   (require 'org)
>>   (org-string-display
>>    (propertize " " 'display '(image :type svg
>>                                     :file "/path/to/image.svg")))
>>
>> This gives the following error backtrace:
>>
>> Debugger entered--Lisp error: (wrong-type-argument sequencep t)
>
> `org-string-display' doesn't exist anymore in master (Org 9.2). However,
> there is the same error with `org-string-width'. 
>
> What is `org-string-width' supposed to do on your example? Probably
> return an error.

I realise that the 'display' property is a pretty complicated beast, so
it may be impractical for 'org-string-width' to do this, but I think
more accurate/useful behaviour would be to calculate the displayed width
of the image via 'image-size' or 'image-display-size', rather than
signalling an error.

>> I realise that org-string-display is a relatively obscure function that
>> was probably not designed with image or other complex display properties
>> in mind, but AFAICT the following is a pretty obvious "fix", given that
>> the surrounding code expects 'value' to be a string or nil, but never t:
>>
>> diff --git a/lisp/org/org-macs.el b/lisp/org/org-macs.el
>> index 583633605f..5ab069e6a2 100644
>> --- a/lisp/org/org-macs.el
>> +++ b/lisp/org/org-macs.el
>> @@ -108,7 +108,7 @@ org-string-display
>>  		       ;; string (face...).
>>  		       (let* ((display (plist-get props 'display))
>>  			      (value (if (stringp display) display
>> -				       (cl-some #'stringp display))))
>> +                                       (cl-find-if #'stringp display))))
>>  			 (when value
>>  			   (apply #'propertize
>>  				  ;; Displayed string could contain
>>
>>
>> With this change, the return value of org-string-display does not really
>> make sense for images, but at least the function doesn't barf on complex
>> but valid display properties.  WDYT?
>
> If `org-string-width' returns nil, it will ensue an error somewhere
> further in the code. So returning an error right here is better (or
> find a way to compute the width of an image in columns).

Why/when would 'org-string-width' return nil?  My suggestion was to
replace 'cl-some' with 'cl-find-if', because the value of
(cl-some #'stringp ...) is a boolean, not a sequence.

To clarify - I am not suggesting that 'org-string-width' should never
signal an error; I am only suggesting that the current
(wrong-type-argument sequencep t) error is due to inappropriate use of
'cl-some'.  My comments may already be outdated, though, since they
refer to the version of org-macs.el shipping with latest Emacs master.

> As another data point, `string-width' returns 1 on your example, which
> is probably wrong.

Neither 'string-width' nor 'current-column' take 'display' properties
into account; see e.g. https://emacs.stackexchange.com/q/44495/15748.
But that's an Emacs feature request of its own.

Thanks,

-- 
Basil

Re: Bug: org-string-display throws on image display property [9.1.9 (release_9.1.9-65-g5e4542 @ /home/blc/.local/share/emacs/27.0.50/lisp/org/)]

[Nicolas Goaziou]

Hello,

"Basil L. Contovounesios" <contovob@tcd.ie> writes:

> I realise that the 'display' property is a pretty complicated beast, so
> it may be impractical for 'org-string-width' to do this, but I think
> more accurate/useful behaviour would be to calculate the displayed width
> of the image via 'image-size' or 'image-display-size', rather than
> signalling an error.

Fixed. `org-string-width' has now a limited support for images.

Thank you.

Regards,

-- 
Nicolas Goaziou