Re: Async rebuild package-quickstart after packages update? was Re: 28.0.50; Proposal: slightly more efficient package-quickstart.el

[Stefan Monnier <monnier@iro.umontreal.ca>]

> One place where we could gain perceptible speedup is when
> package-quickstart is rebuilt after updating packages; could we make
> that function asyn?

Yes, that would be a welcome change.


        Stefan


> Stefan Monnier <monnier@iro.umontreal.ca> writes:
>
>>>>> Not so much, but it is not so much about noticable difference, more
>>>>> about not performing unnecessary computation.
>>> I agree that simplicity and code clarity is important, on many
>>> levels. But maybe we can have the cake and it it too, as you said 
>>> for wdired?
>>
>> In the case of wdired there was a concrete gain.
>> Here it's only hypothetical, so the positive motivation is quite different.
>> Also `package-quickstart` is fairly tricky to troubleshoot (beyond removing
>> or refreshing the file).  To the end user it's largely a magical button,
>> so it's really important to make it work reliably.
>>
>> IOW the incentives are strongly opposed to your proposition.
>>
>>> Last weekend I tested actually myself to restructure how my packages are
>>> loaded. I noticed that init time increased after I added ~100 packages,
>>> just for test, and I didn't required anything of that into Emacs. So I
>>> tested the idea to put all .elc file into a single place and skipp in
>>> entirety this monstrosity of load-path that results after 200 packages
>>> are loaded. I got it to work to a degree, it least I got running Emacs,
>>> native compiler not complaining and most packages loaded, but I also got
>>> some cyclic dependency, notably for dired and semantic of all things,
>>> that actually rendered entire session unusable for the most part. I'll
>>> leave that for another day when I have some more time.
>>
>> Moving the .elc files to a separate (short) list of directories indeed
>> one way we could address the situation where there are too many entries
>> on `load-path`.
>>
>> Another way would be to scan `load-path` "once" and populate
>> a hash-table from that, after which (load "foo" ...) could be sped up by
>> looking up "foo" in the hash-table.
>>
>> Still, that presumes that finding a file is the main issue, but I don't
>> know if that would indeed be true.
>>
>>> (when (re-search-forward rx-path-beg nil t)
>>>             (goto-char (line-beginning-position))
>>>             (setq temp-point (point))
>>>             (forward-sexp)
>>>             (when (search-backward file nil t 1)
>>>               (goto-char temp-point)
>>>               (kill-sexp)))
>>
>> I'd do something like
>>
>>     (while (re-search-forward "^(add-to-list" nil t)
>>       (goto-char (match-beginning 0))
>>         (let ((start (point))
>>               (x (read (current-buffer))))
>>           ...)))
>>
>>
>> -- Stefan
>>
>>