Unnecessarily moving stiff between files considered harmful (Was: [Emacs-diffs] master b88e7c8: Make transpose-regions interactive) (Bug#30343)

[Eli Zaretskii <eliz@gnu.org>]

> From: Karl Fogel <kfogel@red-bean.com>
> Date: Thu, 22 Mar 2018 00:30:24 -0500
> 
> >  . moving code between files makes forensics harder ("git log -L" and
> >    its ilk become almost useless, for example)
> 
> True.

Btw, if I'm allowed a gripe: we have too much of this in our history
already.  Just recently I wanted to know when the assertion in
set_blv_found was born, and was unable to determine this using Git,
because that function was first a macro, then an inline function, and
migrated between 2 or 3 files several times.  I eventually had to use
ChangeLog files from old Emacs releases(!) to find out the history of
this single line.  I'm sure Git gurus will come up with some
convoluted way to do that with Git, and Magit gurus will tell that
Magit already knows how to do this.  But the fact that the usual tools
of trade fail here is for me a clear indication that we should keep
this disadvantage in mind when making such changes: there's a non-zero
price here.