Please explain avoiding history simplifications when diffing merges

[Magnus Holmgren <magnus.holmgren@milientsoftware.com>]

Hi (and thanks for a great free tool).

QGit was bitten by 
https://github.com/git/git/commit/0dec322d31db3920872f43bdd2a7ddd282a5be67

It looks like passing --simplify-merges to override the default solves the 
problem, but I still want to ask here because I'm not sure I fully understand 
the reasoning:

> the default history simplification would remove merge commits from 
> consideration if the file "path" matched the second parent.

I guess that means that even if there was a difference relative to the first 
parent, which you wanted to see, the merge commit would be omitted if there's 
no diff relative to the second parent? That's fine, and history simplification 
isn't trivial, but now every merge commit ever is included in the commit log 
of an individual file, even if that file was only added somewhere in the 
middle and never changed since. Is that really desirable? Shouldn't it be 
possible to include only merge commits that are not TREESAME to *all* parents?

Thanks,
-- 
Magnus Holmgren
./¯\_/¯\. Milient
(also holmgren@debian.org)