Re: [PATCH v4 0/3] use mailmap by default in git log

From: Junio C Hamano <gitster@pobox.com>
Date: Jul 11, 2019, 19:30 UTC
Message-ID: <xmqqy314qsgp.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <20190711183727.8058-1-ariadne@dereferenced.org>

Ariadne Conill <ariadne@dereferenced.org> writes:

Show 9 quoted lines

> It is not uncommon for people to change their name or e-mail address.
> To facilitate this, Git provides support for the `.mailmap` file,
> which contains a list of identities and previously used e-mail
> addresses that are associated with that identity.
>
> Unfortunately, while Git's support for the `.mailmap` file is generally
> excellent, I recently discovered that `git log` does not treat the
> mail map file the same as the other tools, instead requiring an
> explicit flag to use the mailmap file.

Make "the other tools" a bit more explicit. Making things consistent is good but which way the consistency should go needs more data than the above to decide.

Even though I personally think it is an OK longer-term end goal, the execution looks too hasty. The normal way we handle a big behaviour change like this is to do the following in steps, in different releases:

 - In the first release, introduce an early adoptor option (say
   log.usemailmap) that can be turned on by the user, but is off by
   default.  IOW, the initial step is "no change in behaviour,
   unless you ask for it".  This step also makes sure that the way
   to disable it for those who opt into the option from the command
   line (i.e.  the --no-use-mailmap option) works well.

 - In the second release, when "git log" is run without command line
   "--[no-]use-mailmap" and "log.usemailmap" is not set by the user,
   give warning about an upcoming flipping of the default, with an
   advice message that the user can squelch the warning by setting
   the option.

 - In the final release, flip the default and remove the warning.

Usually there needs sufficient time between the second step and the third step, so that people will not miss the warning.

Thanks.