git log --name-only improvement: show old file name in rename

[Ed Avis <ed.avis@qmaw.com>]

The git-log manual page says

       --name-only
           Show only names of changed files.

But when a file has been renamed, only the new name is printed, not the 
old.  I think it would be more useful and more correct to print both 
names. 

For example

% git init
Initialized empty Git repository in /home/eda/test/.git/
% touch a
% git add a
% git commit -mx
[master (root-commit) ca81aa7] x
 1 file changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 a
% git mv a b
% git commit -my
[master 7b3925c] y
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename a => b (100%)
% git log --name-only -n 1
commit 7b3925c1ece26d08d79cf9f06bfcb0b38fea611f (HEAD -> master)
Author: Ed Avis <eda@waniasset.com>
Date:   2020-06-11 11:59:34 +0100

    y

b


I would expect that last log message to show the old filename a as well 
as the new filename b.  If you give --no-renames then both filenames are 
shown, of course, but I think it should be possible to detect the 
rename and print out both old and new names.  There is --name-status 
which will print more info including renames, but again I believe 
--name-only should also show both.  Thank you for considering this 
improvement request.

% git --version
git version 2.26.0

-- 
Ed Avis <ed.avis@qmaw.com>