Re: Setting `minibuffer-completion-table` buffer-locally

[Daniel Mendler]

On 4/24/21 4:56 AM, Stefan Monnier wrote:
> Following a long discussion in bug#45474, I'm warming up to the idea to
> install the patch below which changes `completing-read(-default)` such
> that it sets the `minibuffer-completion-*` variables buffer-locally in
> the mini-buffer instead of let-binding them globally.

I am in favor of such a change. In the completion systems or packages 
centered around completion I am involved with (Selectrum, Vertico, 
Marginalia, Consult, Embark, ...) we always followed the style of 
encapsulating minibuffer-local state inside the minibuffer. Let-binding 
the built-in table always seemed  odd. I don't expect breakage from 
these packages. If some issues occur despite my expectations we will fix 
them promptly. It is no problem to fix issues in a backward compatible 
way by always accessing the minibuffer-completion-table via the 
minibuffer, if for some reason the variable is accessed from the context 
of another buffer.

Daniel