Re: about get_maintainer.pl not showing the original author of the modified code

[Joe Perches]

On Thu, 2016-03-03 at 12:09 +0800, Jianyu Zhan wrote:
> On Thu, Mar 3, 2016 at 11:32 AM, Joe Perches <joe@xxxxxxxxxxx> wrote:
> > 
> > with your patch get_maintainer.pl and --git-blame gives:
> > 
> > $ ./scripts/get_maintainer.pl ~/1.diff --git-blame
> > Thomas Gleixner <tglx@xxxxxxxxxxxxx> (commit_signer:20/19=100%,authored:7/19=37%,added_lines:73/248=29%,removed_lines:38/119=32%)
> > Peter Zijlstra <peterz@xxxxxxxxxxxxx> (commit_signer:3/19=16%,authored:1/19=5%)
> > Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> (commit_signer:3/19=16%,modified commits:2/3=67%)
> > Davidlohr Bueso <dave@xxxxxxxxxxxx> (commit_signer:3/19=16%,authored:3/19=16%,added_lines:113/248=46%,removed_lines:20/119=17%)
> > Ingo Molnar <mingo@xxxxxxxxxx> (commit_signer:2/19=11%,modified commits:2/3=67%)
> > Dominik Dingel <dingel@xxxxxxxxxxxxxxxxxx> (authored:1/19=5%)
> > Jann Horn <jann@xxxxxxxxx> (authored:1/19=5%)
> > Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> (added_lines:29/248=12%)
> > "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> (added_lines:14/248=6%,removed_lines:49/119=41%)
> > Darren Hart <dvhart@xxxxxxxxxxxxxxx> (modified commits:1/3=33%)
> > Stephen Hemminger <shemminger@xxxxxxxxxxxxxxxxxxxx> (modified commits:1/3=33%)
> > Christian Borntraeger <borntrae@xxxxxxxxxx> (modified commits:1/3=33%)
> > linux-kernel@xxxxxxxxxxxxxxx (open list)
> > 
> > vs
> > 
> > $ ./scripts/get_maintainer.pl ~/1.diff
> > Thomas Gleixner <tglx@xxxxxxxxxxxxx> (commit_signer:20/19=100%,authored:7/19=37%,added_lines:73/248=29%,removed_lines:38/119=32%)
> > Davidlohr Bueso <dave@xxxxxxxxxxxx> (commit_signer:3/19=16%,authored:3/19=16%,added_lines:113/248=46%,removed_lines:20/119=17%)
> > Peter Zijlstra <peterz@xxxxxxxxxxxxx> (commit_signer:3/19=16%)
> > Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> (commit_signer:3/19=16%)
> > Ingo Molnar <mingo@xxxxxxxxxx> (commit_signer:2/19=11%)
> > Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> (authored:1/19=5%)
> > Darren Hart <dvhart@xxxxxxxxxxxxxxx> (authored:1/19=5%)
> > kbuild test robot <fengguang.wu@xxxxxxxxx> (authored:1/19=5%)
> > Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> (added_lines:29/248=12%)
> > "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> (added_lines:14/248=6%,removed_lines:49/119=41%)
> 
> So original author's email would be spit out only if given
> --git-blame, instead of by default,
> which really surprises people.  Since most time we will cc original
> author,  we have to use
> --git-blame explicitly, thus pay the running time cost. So the runtime
>  argument don't stands,
> why not just enable it by default?

Several reasons:

Most of the time, git history isn't used at all
because there is a specific named maintainer.

history isn't always appropriate as the original
authors email address is old and bounces

a .get_maintainer.conf file can be used to set
whatever defaults anyone prefers.