Re: [POLL] Use compat.el in Org?

[Daniel Mendler <mail@daniel-mendler.de>]

On 1/27/23 21:38, Tim Cross wrote:
>> As long as we keep our promise in terms of backward compatibility with
>> older Emacs versions, I'm all for it.
> 
> I would agree. I would also add that even with the use of this package,
> I don't think we should use it to increase the number of versions we
> support as support is not as simple as dropping in a compatibility
> library. 

True. The Compat package cannot fix bugs below the Elisp level or
provide APIs which cannot be backported, e.g., big integer support. If
Org relies on behavior of the Emacs display engine or the C core of a
certain Emacs version, Compat cannot help.

The advantage would be that the maintenance burden of org-compat would
be reduced. Many packages can share the backported functions by
depending on Compat, which will increase robustness and reduce the risk
of unexpected bugs. The community only has to maintain a single set of
backported functions in a single package, instead of scattering
compatibility code across many packages.

> These libraries come with a cost. Often, compatibility code
> does not perform as well and/or is much more complicated and more likely
> to have bugs. The more a version of emacs needs to rely on this library
> to run org-mode, the higher the likelihood performance will be degraded
> or unexpected new bugs are found.

To give some context about the stability aspect - many backported
compatibility functions are copied verbatim from newer Emacs versions.
Every compatibility function provided by Compat is covered by tests,
which are executed via CI on all supported Emacs versions (>= 24.4). I
make sure that no functions are backported which perform much worse such
that they would introduce performance bugs.

Daniel