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, 58 insertions, 0 deletions

diff --git a/third_party/git/t/t6435-merge-sparse.sh b/third_party/git/t/t6435-merge-sparse.sh
new file mode 100755
index 000000000000..74562e123566
--- /dev/null
+++ b/third_party/git/t/t6435-merge-sparse.sh
@@ -0,0 +1,58 @@
+#!/bin/sh
+
+test_description='merge with sparse files'
+
+. ./test-lib.sh
+
+# test_file $filename $content
+test_file () {
+	echo "$2" > "$1" &&
+	git add "$1"
+}
+
+# test_commit_this $message_and_tag
+test_commit_this () {
+	git commit -m "$1" &&
+	git tag "$1"
+}
+
+test_expect_success 'setup' '
+	test_file checked-out init &&
+	test_file modify_delete modify_delete_init &&
+	test_commit_this init &&
+	test_file modify_delete modify_delete_theirs &&
+	test_commit_this theirs &&
+	git reset --hard init &&
+	git rm modify_delete &&
+	test_commit_this ours &&
+	git config core.sparseCheckout true &&
+	echo "/checked-out" >.git/info/sparse-checkout &&
+	git reset --hard &&
+	test_must_fail git merge theirs
+'
+
+test_expect_success 'reset --hard works after the conflict' '
+	git reset --hard
+'
+
+test_expect_success 'is reset properly' '
+	git status --porcelain -- modify_delete >out &&
+	test_must_be_empty out &&
+	test_path_is_missing modify_delete
+'
+
+test_expect_success 'setup: conflict back' '
+	test_must_fail git merge theirs
+'
+
+test_expect_success 'Merge abort works after the conflict' '
+	git merge --abort
+'
+
+test_expect_success 'is aborted properly' '
+	git status --porcelain -- modify_delete >out &&
+	test_must_be_empty out &&
+	test_path_is_missing modify_delete
+'
+
+test_done