Re: [PATCH v6] Implement --first-parent for git rev-list --bisect

Johannes Schindelin [off-list ref] writes:

Hi Tiago,

On Tue, 28 Aug 2018, Tiago Botelho wrote:

quoted

This will enable users to implement bisecting on first parents
which can be useful for when the commits from a feature branch
that we want to merge are not always tested.

This message is still lacking the explanation I asked for, namely for the
lines:

	@@ -329,6 +334,11 @@ static struct commit_list *do_find_bisection(struct commit_list *list,
	 	if (0 <= weight(p))
	 		continue;
	 	for (q = p->item->parents; q; q = q->next) {
	+		if ((bisect_flags & BISECT_FIRST_PARENT)) {
	+			if (weight(q) < 0)
	+				q = NULL;
	+			break;
	+		}
	 	if (q->item->object.flags & UNINTERESTING)
	 		continue;
	 	if (0 <= weight(q))

I've just finished scanning the discussion thread on public-inbox
for v5, v4, v3, v2 and the initial round of this series, but found
your comments only on the tests.  If you have a pointer that would
be great; it also is OK to say what kind of explanation is needed
for that addition again.  

FWIW I too was puzzled about the correctness of the added logic
above, especially the part that reads weight(q) before checking if
it is not UNINTERESTING, but I covered it on a separate message.

I would have preferred to reuse the already existing commits generated in
the `setup` phase rather than generating yet another batch, and to not
introduce an inconsistent way to present a commit graph (compare your
diagram with the one in
https://github.com/git/git/blob/v2.18.0/t/t6002-rev-list-bisect.sh#L64-L90
i.e. *in the same file*)

As I already said in the previous round, I do agree with these.
That is, ...

quoted

diff --git a/t/t6002-rev-list-bisect.sh b/t/t6002-rev-list-bisect.sh
index a66140803..1bc297de5 100755
--- a/t/t6002-rev-list-bisect.sh
+++ b/t/t6002-rev-list-bisect.sh

@@ -263,4 +263,62 @@ test_expect_success 'rev-parse --bisect can default to good/bad refs' '
 	test_cmp expect.sorted actual.sorted
 '
 
+# We generate the following commit graph:
+#
+#   B ------ C
+#  /          \
+# A            FX
+#  \          /
+#   D - CC - EX
+
+test_expect_success 'setup' '
+  test_commit A &&
+  test_commit B &&
+  test_commit C &&
+  git reset --hard A &&
+  test_commit D &&
+  test_commit CC &&
+  test_commit EX &&
+  test_merge FX C
+'

... the above graph construction should not be necessary.  An
earlier part of t6002 would have already created a history of
suitable shape to use for writing the following tests.

quoted

+test_output_expect_success "--bisect --first-parent" 'git rev-list --bisect --first-parent FX ^A' <<EOF
+$(git rev-parse CC)
+EOF
+
+test_output_expect_success "--first-parent" 'git rev-list --first-parent FX ^A' <<EOF
+$(git rev-parse FX)
+$(git rev-parse EX)
+$(git rev-parse CC)
+$(git rev-parse D)
+EOF
+
+test_output_expect_success "--bisect-vars --first-parent" 'git rev-list --bisect-vars --first-parent FX ^A' <<EOF
+bisect_rev='$(git rev-parse CC)'
+bisect_nr=1
+bisect_good=1
+bisect_bad=1
+bisect_all=4
+bisect_steps=1
+EOF
+
+test_expect_success "--bisect-all --first-parent" '
+cat >expect <<EOF &&
+$(git rev-parse CC) (dist=2)
+$(git rev-parse EX) (dist=1)
+$(git rev-parse D) (dist=1)
+$(git rev-parse FX) (dist=0)
+EOF
+
+# Make sure we have the same entries, nothing more, nothing less
+git rev-list --bisect-all --first-parent FX ^A >actual &&
+  sort actual >actual.sorted &&
+  sort expect >expect.sorted &&
+  test_cmp expect.sorted actual.sorted &&
+  # Make sure the entries are sorted in the dist order
+  sed -e "s/.*(dist=\([1-9]*[0-9]\)).*/\1/" actual >actual.dists &&
+  sort -r actual.dists >actual.dists.sorted &&
+  test_cmp actual.dists.sorted actual.dists
+'
+
 test_done
-- 
2.16.3