Re: Keep original author with git merge --squash?

Jeff King [off-list ref] writes:

What happens if there is no "Author:" line in the output?

I've been assuming that we would do what the current code does.
"git commit --amend" for example internally remembers who the
original author was and uses that, without paying any attention to
the result from the editor.  If there is no "Author:", that would
not change.

And I do not think we need to be able to say "Oops, I forgot to pass
the --reset-author option from the command line", personally, so...

So probably a saner thing is that a missing "Author:" line does nothing,

yes and

and using "Author: " (with no text) does a reset.

no (I do not think it is wrong per-se, but I do not think such a
good idea).

Also, on the topic of "merge --squash". I never use it myself, but
having experimented with it due to this thread, I found the template it
sticks into COMMIT_EDITMSG to be horribly unfriendly for munging. For
example, with two simple commits, I get:

    Squashed commit of the following:
    
    commit 6821a8ac920ed00675e4aec10dcef705211105cd
    Author: Jeff King [off-list ref]
    Date:   Thu Feb 12 17:39:28 2015 -0500
    
        commit subject 2
    
        commit body 2
    
    commit b0840bb4bbfe00b6ed8c7c4d483f11d126fa2d69
    Author: Jeff King [off-list ref]
    Date:   Thu Feb 12 17:39:28 2015 -0500
    
        commit subject 1
    
        commit body 1

I guess that is helpful if you want to keep a complete log of what got
squashed, but I doubt that is the common case (if you did, then doing a
real merge would probably be in order).

I think it should show exactly the same thing as "rebase -i" squash
insn would give you.  People already know how to munge that, right?

It also raises a question for the proposal in this thread: if there are
multiple "Author:" lines, which one do we take? The first, or the last?

I was siding with David's "pay attention to in-buffer Author: only
when all of them agree".  When squash-merging a branch with two or
more authors, we would attribute the authorship silently and
automatically to you if you do not do anything special otherwise.

Possible alternatives when multiple "Author:"s do not agree are:

 - use you who is playing the integrator;

 - use the tip;

 - use the one that most often appears; or

 - error out and ask the user to leave only one (or zero--if you
   want to take the authorship) by re-attempting "git commit".