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, 26 insertions, 2 deletions

diff --git a/third_party/git/t/t2024-checkout-dwim.sh b/third_party/git/t/t2024-checkout-dwim.sh
index fa0718c730c3..accfa9aa4bd8 100755
--- a/third_party/git/t/t2024-checkout-dwim.sh
+++ b/third_party/git/t/t2024-checkout-dwim.sh
@@ -37,7 +37,9 @@ test_expect_success 'setup' '
 		git checkout -b foo &&
 		test_commit a_foo &&
 		git checkout -b bar &&
-		test_commit a_bar
+		test_commit a_bar &&
+		git checkout -b ambiguous_branch_and_file &&
+		test_commit a_ambiguous_branch_and_file
 	) &&
 	git init repo_b &&
 	(
@@ -46,7 +48,9 @@ test_expect_success 'setup' '
 		git checkout -b foo &&
 		test_commit b_foo &&
 		git checkout -b baz &&
-		test_commit b_baz
+		test_commit b_baz &&
+		git checkout -b ambiguous_branch_and_file &&
+		test_commit b_ambiguous_branch_and_file
 	) &&
 	git remote add repo_a repo_a &&
 	git remote add repo_b repo_b &&
@@ -75,6 +79,26 @@ test_expect_success 'checkout of branch from multiple remotes fails #1' '
 	test_branch master
 '
 
+test_expect_success 'when arg matches multiple remotes, do not fallback to interpreting as pathspec' '
+	# create a file with name matching remote branch name
+	git checkout -b t_ambiguous_branch_and_file &&
+	>ambiguous_branch_and_file &&
+	git add ambiguous_branch_and_file &&
+	git commit -m "ambiguous_branch_and_file" &&
+
+	# modify file to verify that it will not be touched by checkout
+	test_when_finished "git checkout -- ambiguous_branch_and_file" &&
+	echo "file contents" >ambiguous_branch_and_file &&
+	cp ambiguous_branch_and_file expect &&
+
+	test_must_fail git checkout ambiguous_branch_and_file 2>err &&
+
+	test_i18ngrep "matched multiple (2) remote tracking branches" err &&
+
+	# file must not be altered
+	test_cmp expect ambiguous_branch_and_file
+'
+
 test_expect_success 'checkout of branch from multiple remotes fails with advice' '
 	git checkout -B master &&
 	test_might_fail git branch -D foo &&