Re: [PATCH v3] diff.c: keep arrow(=>) on show_stats()'s shortened filename part to make rename visible.

> Hi,
> 
> Yoshioka Tsuneo <yoshiokatsuneo@gmail.com> writes:
> 
>> "git diff -M --stat" can detect rename and show renamed file name like
>> "foofoofoo => barbarbar", but if destination filename is long the line
>> is shortened like "...barbarbar" so there is no way to know whether the
>> file is renamed or existed in the source commit.
> 
> Thanks for your patch!  I think this is indeed something that should be
> fixed.
> 
> Can you explain the algorithm chosen in the commit message or a block
> comment in the code?  I find it much easier to follow large code blocks
> (like the one you added) with a prior notion of what it tries to do.
> 
>  [As an aside, Documentation/SubmittingPatches says
> 
>    The body should provide a meaningful commit message, which:
> 
>      . explains the problem the change tries to solve, iow, what is wrong
>        with the current code without the change.
> 
>      . justifies the way the change solves the problem, iow, why the
>        result with the change is better.
> 
>      . alternate solutions considered but discarded, if any.
> 
>  Observe that you explained the first item very well, but not the
>  others.]
> 
>> This commit makes it visible like "...foo => ...bar".
> 
> Also, you should rewrite this to be in the imperative mood:
> 
>  Make sure there is always an arrow, e.g., "...foo => ...bar".
> 
> or some such.
> 
>  [Again from SubmittingPatches:
> 
>    Describe your changes in imperative mood, e.g. "make xyzzy do frotz"
>    instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy
>    to do frotz", as if you are giving orders to the codebase to change
>    its behaviour.]
> 
>> Signed-off-by: Tsuneo Yoshioka <yoshiokatsuneo@gmail.com>
>> ---
>> diff.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++-------
>> 1 file changed, 51 insertions(+), 7 deletions(-)
> 
> Can you add a test?  Perhaps like the one below.  (You can squash it
> into your commit if you like it.)
> 
> Note that in the test, the generated line looks like this:
> 
> {..._does_not_fit_in_a_single_line => .../path1                          | 0
> 
> I don't want to go all bikesheddey, but I think it's somewhat
> unfortunate that the elided parts do not correspond to each other.  In
> particular, I think the closing brace should not be omitted.  Perhaps
> something like this would be ideal (making it up on the spot, don't
> count characters):
> 
> {...a_single_line => ..._as_the_first}/path1                          | 0
> 
> diff --git a/t/t4001-diff-rename.sh b/t/t4001-diff-rename.sh
> index 2f327b7..03d6371 100755
> --- a/t/t4001-diff-rename.sh
> +++ b/t/t4001-diff-rename.sh
> @@ -156,4 +156,16 @@ test_expect_success 'rename pretty print common prefix and suffix overlap' '
> 	test_i18ngrep " d/f/{ => f}/e " output
> '
> 
> +test_expect_success 'rename of very long path shows =>' '
> +	mkdir long_dirname_that_does_not_fit_in_a_single_line &&
> +	mkdir another_extremely_long_path_but_not_the_same_as_the_first &&
> +	cp path1 long_dirname*/ &&
> +	git add long_dirname*/path1 &&
> +	test_commit add_long_pathname &&
> +	git mv long_dirname*/path1 another_extremely_*/ &&
> +	test_commit move_long_pathname &&
> +	git diff -M --stat HEAD^ HEAD >output &&
> +	test_i18ngrep "=>.*path1" output
> +'
> +
> test_done
> 
> -- 
> Thomas Rast
> tr@thomasrast.ch