Re: Suggestion: convert dispatchers to use transient

[Jim Porter <jporterbugs@gmail.com>]

On 2/3/2022 1:30 PM, Tim Cross wrote:
> Is the transient.el included in Emacs 28 the same as the one on GNU
> ELPA?

Currently, yes. They're both 0.3.7. However, that could obviously change 
in the future (e.g. a user on 28.1 would likely have transient 0.3.7, 
though GNU ELPA might have transient 0.3.8 if it were released one day).

> I'm assuming it is, but I have to admit I'm still not 100% clear
> on how Emacs handles the situation where you use a library that is both
> built-in and available in ELPA. Does Emacs use the latest version
> available or does it use the built-in version until you explicitly
> select the ELPA versions?
Emacs will use the built-in version of a package provided that package 
meets the version requirements. For the version of Org Mode that comes 
with Emacs, it would always use the built-in transient (largely because 
maintainers wouldn't do it any other way). If you download a newer Org 
version from GNU ELPA, I believe it checks the package metadata and then 
will fetch transient from GNU ELPA as well if the built-in version is 
too old.

(I haven't looked at the code to verify this, but it's how Eglot worked 
when I installed it. Eglot wants newer versions of eldoc, xref, project, 
etc than Emacs 27.2 provides, so package.el automatically installs them 
when installing Eglot.)

- Jim