merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 92 insertions, 0 deletions

diff --git a/third_party/git/t/t6408-merge-up-to-date.sh b/third_party/git/t/t6408-merge-up-to-date.sh
new file mode 100755
index 0000000000..7763c1ba98
--- /dev/null
+++ b/third_party/git/t/t6408-merge-up-to-date.sh
@@ -0,0 +1,92 @@
+#!/bin/sh
+
+test_description='merge fast-forward and up to date'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+	>file &&
+	git add file &&
+	test_tick &&
+	git commit -m initial &&
+	git tag c0 &&
+
+	echo second >file &&
+	git add file &&
+	test_tick &&
+	git commit -m second &&
+	git tag c1 &&
+	git branch test &&
+	echo third >file &&
+	git add file &&
+	test_tick &&
+	git commit -m third &&
+	git tag c2
+'
+
+test_expect_success 'merge -s recursive up-to-date' '
+
+	git reset --hard c1 &&
+	test_tick &&
+	git merge -s recursive c0 &&
+	expect=$(git rev-parse c1) &&
+	current=$(git rev-parse HEAD) &&
+	test "$expect" = "$current"
+
+'
+
+test_expect_success 'merge -s recursive fast-forward' '
+
+	git reset --hard c0 &&
+	test_tick &&
+	git merge -s recursive c1 &&
+	expect=$(git rev-parse c1) &&
+	current=$(git rev-parse HEAD) &&
+	test "$expect" = "$current"
+
+'
+
+test_expect_success 'merge -s ours up-to-date' '
+
+	git reset --hard c1 &&
+	test_tick &&
+	git merge -s ours c0 &&
+	expect=$(git rev-parse c1) &&
+	current=$(git rev-parse HEAD) &&
+	test "$expect" = "$current"
+
+'
+
+test_expect_success 'merge -s ours fast-forward' '
+
+	git reset --hard c0 &&
+	test_tick &&
+	git merge -s ours c1 &&
+	expect=$(git rev-parse c0^{tree}) &&
+	current=$(git rev-parse HEAD^{tree}) &&
+	test "$expect" = "$current"
+
+'
+
+test_expect_success 'merge -s subtree up-to-date' '
+
+	git reset --hard c1 &&
+	test_tick &&
+	git merge -s subtree c0 &&
+	expect=$(git rev-parse c1) &&
+	current=$(git rev-parse HEAD) &&
+	test "$expect" = "$current"
+
+'
+
+test_expect_success 'merge fast-forward octopus' '
+
+	git reset --hard c0 &&
+	test_tick &&
+	git merge c1 c2 &&
+	expect=$(git rev-parse c2) &&
+	current=$(git rev-parse HEAD) &&
+	test "$expect" = "$current"
+'
+
+test_done