bug#20717: attribution of gitmerge.el merged entries in generated ChangeLog

[Glenn Morris <rgm@gnu.org>]

Glenn Morris wrote:

> Eli Zaretskii wrote:
>
>> I'm guessing that you are using "git log" to show this. 
>
> No, I'm using `make ChangeLog' like I said in the original message.
> This produces a ChangeLog which is a confusing mess where merges are
> involved.

To expand:
1. The dates of merged entries are wrong by an arbitrary amount.
You can see the "cairo" entries in current ChangeLog.2 for an example of
this. IIUC, this isn't fixable without getting the reflog involved.
Ref: http://lists.gnu.org/archive/html/emacs-devel/2014-12/msg00102.html

2. Entries that were "skipped" when gitmerge.el'ing from emacs-24 to
master still appear in the generated ChangeLog. Check tomorrow's
automatically updated ChangeLog.2 for examples of that. Or type `make
ChangeLog' today. You'll see entries like

2015-04-11  Ulrich Mueller <ulm>

       Bump Emacs version to 24.5.50.

that were skipped when merging from emacs-24. It's especially confusing
because if merging isn't done very often (and recent history suggests it
won't be), these entries will be offset from the relevant "Merge from
origin/emacs-24" entry by a large distance. This isn't an issue now
because the emacs-24 branch is basically dead, but it will be for the
next release.

I would hope that this one is fixable, with some work on admin/gitmerge.el
and/or build-aux/gitlog-to-changelog.

But I get the impression that a readable ChangeLog isn't much of a
priority for Emacs anymore. Maybe no-one will miss it.