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 b520abf ("sequencer: warn when internal
merge may be suboptimal due to renameLimit", 2017-11-14) treated 0 as a
special value indicating that the rename limit is to be a very large
number instead.
The commit b520abf 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 allow
"-l0") 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>
---
Note that this patch is built on en/rename-progress.
We noticed this through an automated test for an internal tool - the
tool uses git diff-tree with -l0, and no longer produces the same
results as before.
---
diffcore-rename.c | 2 ++
t/t4001-diff-rename.sh | 15 +++++++++++++++
2 files changed, 17 insertions(+)
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
--
2.15.0.173.g9268cf4a2.dirty
