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, 100 insertions, 0 deletions

diff --git a/third_party/git/t/t6411-merge-filemode.sh b/third_party/git/t/t6411-merge-filemode.sh
new file mode 100755
index 0000000000..87741efad3
--- /dev/null
+++ b/third_party/git/t/t6411-merge-filemode.sh
@@ -0,0 +1,100 @@
+#!/bin/sh
+
+test_description='merge: handle file mode'
+. ./test-lib.sh
+
+test_expect_success 'set up mode change in one branch' '
+	: >file1 &&
+	git add file1 &&
+	git commit -m initial &&
+	git checkout -b a1 master &&
+	: >dummy &&
+	git add dummy &&
+	git commit -m a &&
+	git checkout -b b1 master &&
+	test_chmod +x file1 &&
+	git add file1 &&
+	git commit -m b1
+'
+
+do_one_mode () {
+	strategy=$1
+	us=$2
+	them=$3
+	test_expect_success "resolve single mode change ($strategy, $us)" '
+		git checkout -f $us &&
+		git merge -s $strategy $them &&
+		git ls-files -s file1 | grep ^100755
+	'
+
+	test_expect_success FILEMODE "verify executable bit on file ($strategy, $us)" '
+		test -x file1
+	'
+}
+
+do_one_mode recursive a1 b1
+do_one_mode recursive b1 a1
+do_one_mode resolve a1 b1
+do_one_mode resolve b1 a1
+
+test_expect_success 'set up mode change in both branches' '
+	git reset --hard HEAD &&
+	git checkout -b a2 master &&
+	: >file2 &&
+	H=$(git hash-object file2) &&
+	test_chmod +x file2 &&
+	git commit -m a2 &&
+	git checkout -b b2 master &&
+	: >file2 &&
+	git add file2 &&
+	git commit -m b2 &&
+	{
+		echo "100755 $H 2	file2"
+		echo "100644 $H 3	file2"
+	} >expect
+'
+
+do_both_modes () {
+	strategy=$1
+	test_expect_success "detect conflict on double mode change ($strategy)" '
+		git reset --hard &&
+		git checkout -f a2 &&
+		test_must_fail git merge -s $strategy b2 &&
+		git ls-files -u >actual &&
+		test_cmp expect actual &&
+		git ls-files -s file2 | grep ^100755
+	'
+
+	test_expect_success FILEMODE "verify executable bit on file ($strategy)" '
+		test -x file2
+	'
+}
+
+# both sides are equivalent, so no need to run both ways
+do_both_modes recursive
+do_both_modes resolve
+
+test_expect_success 'set up delete/modechange scenario' '
+	git reset --hard &&
+	git checkout -b deletion master &&
+	git rm file1 &&
+	git commit -m deletion
+'
+
+do_delete_modechange () {
+	strategy=$1
+	us=$2
+	them=$3
+	test_expect_success "detect delete/modechange conflict ($strategy, $us)" '
+		git reset --hard &&
+		git checkout $us &&
+		test_must_fail git merge -s $strategy $them
+	'
+}
+
+do_delete_modechange recursive b1 deletion
+do_delete_modechange recursive deletion b1
+do_delete_modechange resolve b1 deletion
+do_delete_modechange resolve deletion b1
+
+test_done