Re: Regression in dump-emacs-portable

[Eli Zaretskii <eliz@gnu.org>]

> From: Lynn Winebarger <owinebar@gmail.com>
> Date: Thu, 16 Feb 2023 04:31:10 -0500
> Cc: emacs-devel <emacs-devel@gnu.org>
> 
>  > Almost every library in 28.2 could be redumped, excepting those which
>  > simply failed to load for whatever reason.
> 
>  Don't we have Lisp objects that cannot be dumped?  If we do, then not
>  every library could be dumped even in principle.
> 
> In 28.2, using dump-emacs-portable, the answer is, not many in the libraries in included in the Emacs
> source distribution.  I excluded the term and obsolete subdirectories from generating the set of libraries to
> dump (but not from the final set determined from load-history).

Is exclusion really the way to go, if we want eventually to support
re-dumping at any given moment?

>  Another potential issue with this is (assuming you suggest to actually
>  try dumping every library) that it will take too long, and thus will
>  be likely to be skipped in any "normal" run of the test suite, thus
>  missing the point.
> 
> My 2017-vintage laptop dumps the 1252 files, including all of leim, in 34 seconds, for a 135MB dump file.
> When I added leim to the exclusions list,  1172 libraries are dumped in 24 seconds for a 83MB dump file,
> which explains why my effort with 30.0.50 produces a 75MB dump.

That's a lot.  And I presume your build is optimized?  So an
unoptimized build will be slower.  Running such slow tests routinely
is a PITA, so such a test will probably moved to a category that
doesn't run by default.

> Aside from testing on a per-commit basis, isn't there a
> more comprehensive set of regression tests run pre-release? Does emacs have a CI process regularly
> running the test suite, or is it more ad hoc?

There's EMBA.