Re: Incrementally updating completion UI - caching issues with Tramp

[Daniel Mendler]

On 5/8/21 1:49 PM, Michael Albinus wrote:
> You've mentioned non-essential in the github thread. I recommend to use
> it (let-bind it somewhere to t), because it is designed mainly for
> completion packages. It's documentation mentions disturbing password
> prompts, but it does also some other optimization in Tramp for file name
> completion. Perhaps, It could also of help for your other issue #23.

Thank you, I will let-bind `non-essential` then.
> Tramp has caching built-in. This is controlled by user option
> remote-file-name-inhibit-cache. Per default, file name caches are kept
> for 10 seconds, but this can be changed. You shall recommend your users
> at least not to set it to t, which would disable (inhibit) Tramp's
> cache.
> 
> Tramp caches the result of the function file-name-all-completions for
> that defined period; 10 seconds have been proven to be sufficient. I
> don't know which function is used by the Verico package to access Tramp;
> if it is another one you might have problems.

This is good to hear. Vertico and Icomplete both access Tramp only via
the file completion table `completion--file-name-table` via
`read-file-name-default`. These are the default facilities. There is no
special file handling in Vertico and Icomplete.

> As a beginning, I recommend you to check, how Tramp is plugged into
> Vertico. For example, you might open a remote connection. Set
> tramp-verbose to 10, and try to use Vertico for file name completion,
> some few characters. When done, reset tramp-verbose to its previous
> value (3, if you haven't touched it). There will be a Tramp debug
> buffer, which you might send for analysis.

This is also a good advice. I will give this a try. If I have further
questions I will send you another mail. Thank you for your answers so far!

Daniel