Documentation: Side effects of org-entry-properties and others

Documentation: Side effects of org-entry-properties and others

[D]

Hi,

it seems a few functions meant to expose org internals to programmers
seem to cause undocumented side effects.  A particular example being
org-entry-properties.  When called, it changes the match-data.  This can
cause issues in cases where leaking match-data can cause font-lock to
behave inconsistently or throw errors.  I think it would be a good idea
to add a prominent warning to such interfacing functions, or document it
somewhere in the module.

The same is true for org-element-lineage, but I am not so sure whether
it is intended for hacking purposes as much as org-entry-properties.
Sadly, I have no overview over the scope of this issue, so I do not know
whether my suggestion is unrealistic (for example, because it would mean
adding warnings practically everywhere).

Regards,

D.

Re: Documentation: Side effects of org-entry-properties and others

[John Kitchin]

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I guess org-element-context and (org-element-at-point) also do this too (or
at least once did), because I have code that wraps them in save-match data
with notes to my self that match-data changes.

There are other things that unexpectedly do this, like split-string I think
(again based on code using this that is wrapped in save-match-data).


John

-----------------------------------
Professor John Kitchin
Doherty Hall A207F
Department of Chemical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
412-268-7803
@johnkitchin
http://kitchingroup.cheme.cmu.edu



On Mon, Feb 17, 2020 at 6:20 PM D <d.williams@posteo.net> wrote:

> Hi,
>
> it seems a few functions meant to expose org internals to programmers
> seem to cause undocumented side effects.  A particular example being
> org-entry-properties.  When called, it changes the match-data.  This can
> cause issues in cases where leaking match-data can cause font-lock to
> behave inconsistently or throw errors.  I think it would be a good idea
> to add a prominent warning to such interfacing functions, or document it
> somewhere in the module.
>
> The same is true for org-element-lineage, but I am not so sure whether
> it is intended for hacking purposes as much as org-entry-properties.
> Sadly, I have no overview over the scope of this issue, so I do not know
> whether my suggestion is unrealistic (for example, because it would mean
> adding warnings practically everywhere).
>
> Regards,
>
> D.
>
>

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Re: Documentation: Side effects of org-entry-properties and others

[Nicolas Goaziou]

Hello,

D <d.williams@posteo.net> writes:

> The same is true for org-element-lineage, but I am not so sure whether
> it is intended for hacking purposes as much as org-entry-properties.
> Sadly, I have no overview over the scope of this issue, so I do not know
> whether my suggestion is unrealistic (for example, because it would mean
> adding warnings practically everywhere).

I think this is unrealistic. If you need to save match data, execute
non-trivial code, and use the saved match data, I suggest to use
`save-match-data'.

Regards,

-- 
Nicolas Goaziou