Remove the line length limit for graft files

Support for grafts predates Git's strbuf, and hence it is understandable
that there was a hard-coded line length limit of 1023 characters (which
was chosen a bit awkwardly, given that it is *exactly* one byte short of
aligning with the 41 bytes occupied by a commit name and the following
space or new-line character).

While regular commit histories hardly win comprehensibility in general
if they merge more than twenty-two branches in one go, it is not Git's
business to limit grafts in such a way.

In this particular developer's case, the use case that requires
substantially longer graft lines to be supported is the visualization of
the commits' order implied by their changes: commits are considered to
have an implicit relationship iff exchanging them in an interactive
rebase would result in merge conflicts.

Thusly implied branches tend to be very shallow in general, and the
resulting thicket of implied branches is usually very wide; It is
actually quite common that *most* of the commits in a topic branch have
not even one implied parent, so that a final merge commit has about as
many implied parents as there are commits in said branch.

[jc: squashed in tests by Jonathan]

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/t/t6101-rev-parse-parents.sh b/t/t6101-rev-parse-parents.sh
index 7ea14ce..10b1452 100755
--- a/t/t6101-rev-parse-parents.sh
+++ b/t/t6101-rev-parse-parents.sh
@@ -20,7 +20,17 @@ test_expect_success 'setup' '
 	test_commit start2 &&
 	git checkout master &&
 	git merge -m next start2 &&
-	test_commit final
+	test_commit final &&
+
+	test_seq 40 |
+	while read i
+	do
+		git checkout --orphan "b$i" &&
+		test_tick &&
+		git commit --allow-empty -m "$i" &&
+		commit=$(git rev-parse --verify HEAD) &&
+		printf "$commit " >>.git/info/grafts
+	done
 '
 
 test_expect_success 'start is valid' '
@@ -79,6 +89,10 @@ test_expect_success 'final^1^! = final^1 ^final^1^1 ^final^1^2' '
 	test_cmp expect actual
 '
 
+test_expect_success 'large graft octopus' '
+	test_cmp_rev_output b31 "git rev-parse --verify b1^30"
+'
+
 test_expect_success 'repack for next test' '
 	git repack -a -d
 '