bug#21998: Run 'make change-history' on release branch

[Eli Zaretskii]

> From: Richard Stallman <rms@gnu.org>
> Date: Mon, 07 Mar 2016 01:51:17 -0500
> Cc: 21998@debbugs.gnu.org
> 
> > At this point, I give up, since it seems fairly clear that maintaining
>   > an accurate ChangeLog just isn't of interest. Even the bare minimum
>   > legally relevant mistakes (missing "tiny change") don't seem to be being
>   > corrected.
> 
> In concrete terms, what is the problem with these mistakes?

The mistakes are not being corrected.  Experience shows that
correcting them is enough of an annoyance to discourage people.

> Where is the master record of this information now?

In the Git commit messages.

> Is it being maintained correctly there?

When a mistake is made there, it cannot be corrected, because Git
commit log is immutable.  Corrections must be made manually to a
ChangeLog file produced from the Git log by a script.  That proved not
to work well, see above.  It also proved to be a non-trivial problem
when merging changes from the release branch to master -- for this
latter issue we still don't have any idea for how to solve it reliably
and without requiring a lot of manual labor.

>                Probably just deleting it from the repo would be more honest.
> 
> What exactly are you proposing as the new practice
> for handling ChangeLog files?

There are 3 possibilities:

  . Keep the current system, where ChangeLog is produced from Git log
    and mistakes made in Git log should be corrected manually after
    producing ChangeLog

  . Give up on having ChangeLog files, either produced from Git log or
    maintained in the repository -- meaning a tarball will not include
    any ChangeLog at all

  . Go back to previous practice where we maintained ChangeLog files
    in the repository, and Git log messages were just copies of the
    ChangeLog entries