[PATCH v2 3/3] completion: 'git checkout' completes untracked paths as a last resort

We taught 'git checkout' to first try to complete revisions (unless
'--' is present on the command line) and, failing that, to complete
tracked paths.  If this yields nothing, it lets the Bash default,
which offers paths in $PWD, kick in.

Teach it to complete untracked paths before giving up and letting
the Bash default kick in.  With this change,

    $ git -C another-directory checkout un<TAB>

finds the 'untracked' file in another-directory and offers it as a
completion candidate.

Signed-off-by: Junio C Hamano <[email protected]>
---
 contrib/completion/git-completion.bash |  4 ++++
 t/t9902-completion.sh                  | 21 +++++++++++++++++++--
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 0eecfcbf8b..22c53697ab 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -1784,6 +1784,10 @@ _git_checkout ()
 	if [ ${#COMPREPLY[@]} -eq 0 ]; then
 		__git_complete_index_file ""
 	fi
+
+	if [ ${#COMPREPLY[@]} -eq 0 ]; then
+		__git_complete_index_file "--others"
+	fi
 }
 
 __git_sequencer_inprogress_options="--continue --quit --abort --skip"
diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index 13fa5c65c3..e8418f069b 100755
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh
@@ -2727,9 +2727,19 @@ test_expect_success 'git checkout completes tracked paths when no refs match' '
 	EOF
 '
 
+test_expect_success 'git checkout completes untracked paths, too' '
+	# ufile is not tracked and there is no ref that begins with u
+	test_completion "git checkout u" <<-\EOF &&
+	ufile
+	EOF
+	test_completion "git checkout -- u" <<-\EOF
+	ufile
+	EOF
+'
+
 test_expect_success 'git -C <path> checkout completes paths in specified repo' '
 	# otherfile is tracked, oops is not
-	# lostfile is tracked but lost
+	# lostfile is tracked but lost, ufile is untracked.
 	test_when_finished "rm -rf repo-for-checkout" &&
 	git init repo-for-checkout &&
 	echo content >repo-for-checkout/otherfile &&
@@ -2738,6 +2748,7 @@ test_expect_success 'git -C <path> checkout completes paths in specified repo' '
 	git -C repo-for-checkout add lostfile &&
 	git -C repo-for-checkout commit -m otherfile &&
 	echo untracked >repo-for-checkout/oops &&
+	echo untracked >repo-for-checkout/ufile &&
 	rm -f repo-for-checkout/lostfile &&
 	test_completion "git -C repo-for-checkout checkout o" <<-\EOF &&
 	otherfile
@@ -2748,9 +2759,15 @@ test_expect_success 'git -C <path> checkout completes paths in specified repo' '
 	test_completion "git -C repo-for-checkout checkout l" <<-\EOF &&
 	lostfile
 	EOF
-	test_completion "git -C repo-for-checkout checkout -- l" <<-\EOF
+	test_completion "git -C repo-for-checkout checkout -- l" <<-\EOF &&
 	lostfile
 	EOF
+	test_completion "git -C repo-for-checkout checkout u" <<-\EOF &&
+	ufile
+	EOF
+	test_completion "git -C repo-for-checkout checkout -- u" <<-\EOF
+	ufile
+	EOF
 '
 
 test_expect_success 'git diff completes tracked paths when no refs match' '
-- 
2.55.0-721-g26b8014fc4