bug#54977: 29.0.50; Customising eshell-modules-list means you won't get new default entries

[Sean Whitton <spwhitton@spwhitton.name>]

Hello,

On Sun 17 Apr 2022 at 08:28am +03, Eli Zaretskii wrote:

>> From: Sean Whitton <spwhitton@spwhitton.name>
>> Date: Sat, 16 Apr 2022 13:55:22 -0700
>>
>> Suppose that you use the customisation interface to enable the
>> eshell-rebind module, and save the result in your init.  Now upstream
>> Emacs gains a new on-by-default module, e.g. the recently added
>> em-extpipe.  While everyone who hasn't customised eshell-modules-list
>> gets the new module automatically, you'll have to customise the variable
>> again, and you can't even just tick a box to add it, as with the other
>> truly optional modules, but must manually insert it at the end of the
>> list.  This is no good.
>>
>> How about using two separate defcustoms for these two kinds of entry?
>
> One other idea is to have the default modules not mentioned
> explicitly, but instead have some kind of placeholder which stands for
> all the default modules.  Similar to some path variables that treat an
> empty or nil list member as standing for the default value.

That would be nicer than two defcustoms, I think.  Possibly it could be
an uber-module which just pulls in the defaults.

-- 
Sean Whitton