Jonathan Tan wrote:
> In the documentation of diff-tree, it is stated that the -l option
> "prevents rename/copy detection from running if the number of
> rename/copy targets exceeds the specified number". The documentation
> does not mention any special handling for the number 0, but the
> implementation before commit 9f7e4bfa3b ("diff: remove silent clamp of
> renameLimit", 2017-11-13) treated 0 as a special value indicating that
> the rename limit is to be a very large number instead.
>
> The commit 9f7e4bfa3b changed that behavior, treating 0 as 0. Revert
> this behavior to what it was previously. This allows existing scripts
> and tools that use "-l0" to continue working. The alternative (to have
> "-l0" suppress rename detection) is probably much less useful, since
> users can just refrain from specifying -M and/or -C to have the same
> effect.
>
> Signed-off-by: Jonathan Tan <jonathantanmy@xxxxxxxxxx>
> ---
> v2 is exactly the same as previously, except that the commit message is
> changed following Elijah Newren's and Jonathan Nieder's comments.
>
> diffcore-rename.c | 2 ++
> t/t4001-diff-rename.sh | 15 +++++++++++++++
> 2 files changed, 17 insertions(+)
Reviewed-by: Jonathan Nieder <jrnieder@xxxxxxxxx>
Thanks again.
> diff --git a/diffcore-rename.c b/diffcore-rename.c
> index 9ca0eaec7..245e999fe 100644
> --- a/diffcore-rename.c
> +++ b/diffcore-rename.c
> @@ -392,6 +392,8 @@ static int too_many_rename_candidates(int num_create,
> *
> * num_create * num_src > rename_limit * rename_limit
> */
> + if (rename_limit <= 0)
> + rename_limit = 32767;
> if ((num_create <= rename_limit || num_src <= rename_limit) &&
> ((uint64_t)num_create * (uint64_t)num_src
> <= (uint64_t)rename_limit * (uint64_t)rename_limit))
> diff --git a/t/t4001-diff-rename.sh b/t/t4001-diff-rename.sh
> index 0d1fa45d2..eadf4f624 100755
> --- a/t/t4001-diff-rename.sh
> +++ b/t/t4001-diff-rename.sh
> @@ -230,4 +230,19 @@ test_expect_success 'rename pretty print common prefix and suffix overlap' '
> test_i18ngrep " d/f/{ => f}/e " output
> '
>
> +test_expect_success 'diff-tree -l0 defaults to a big rename limit, not zero' '
> + test_write_lines line1 line2 line3 >myfile &&
> + git add myfile &&
> + git commit -m x &&
> +
> + test_write_lines line1 line2 line4 >myotherfile &&
> + git rm myfile &&
> + git add myotherfile &&
> + git commit -m x &&
> +
> + git diff-tree -M -l0 HEAD HEAD^ >actual &&
> + # Verify that a rename from myotherfile to myfile was detected
> + grep "myotherfile.*myfile" actual
> +'
> +
> test_done
