Re: Turning on savehist-mode by default

[Dmitry Gutov]

On 28/11/2023 23:07, Adam Porter wrote:
> FWIW, IME, it may not be a good idea to enable savehist-mode by default. 
>   As an example, see this issue report on Ement.el's repository:
>
> https://github.com/alphapapa/ement.el/issues/216
>
> The gist is that, for users who enabled savehist, it was saving the 
> variable command-history, which included some complex commands whose 
> arguments (from interactive completion) included large data structures 
> (which are hidden from the user when called interactively).  This 
> resulted in savehist files hundreds of MB in size and very noticeable 
> pauses whenever savehist saved its data, from timers and upon Emacs exit.

savehist-mode is very popular, so even if it's not on by default, such 
issues might be encountered by a lot of people anyway.

Could we try to fix it for those users? Either by filtering out 
"expensive" entries before saving (with some heuristic), or by entirely 
blacklisting command-history by default -- through 
savehist-ignored-variables.