[PATCH 2/2] built-in add -i: accept open-ended ranges again

["Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

The interactive `add` command allows selecting multiple files for some
of its sub-commands, via unique prefixes, indices or index ranges.

When re-implementing `git add -i` in C, we even added a code comment
talking about ranges with a missing end index, such as `2-`, but the
code did not actually accept those, as pointed out in
https://github.com/git-for-windows/git/issues/2466#issuecomment-574142760.

Let's fix this, and add a test case to verify that this stays fixed
forever.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-interactive.c          | 5 ++++-
 t/t3701-add-interactive.sh | 9 +++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/add-interactive.c b/add-interactive.c
index 14d4688c26..396066e724 100644
--- a/add-interactive.c
+++ b/add-interactive.c
@@ -328,7 +328,10 @@ static ssize_t list_and_choose(struct add_i_state *s,
 				if (endp == p + sep)
 					to = from + 1;
 				else if (*endp == '-') {
-					to = strtoul(++endp, &endp, 10);
+					if (isdigit(*(++endp)))
+						to = strtoul(endp, &endp, 10);
+					else
+						to = items->items.nr;
 					/* extra characters after the range? */
 					if (endp != p + sep)
 						from = -1;
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index d4f9386621..b02fe73631 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -57,6 +57,15 @@ test_expect_success 'revert works (initial)' '
 	! grep . output
 '
 
+test_expect_success 'add untracked (multiple)' '
+	test_when_finished "git reset && rm [1-9]" &&
+	touch $(test_seq 9) &&
+	test_write_lines a "2-5 8-" | git add -i -- [1-9] &&
+	test_write_lines 2 3 4 5 8 9 >expected &&
+	git ls-files [1-9] >output &&
+	test_cmp expected output
+'
+
 test_expect_success 'setup (commit)' '
 	echo baseline >file &&
 	git add file &&
-- 
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