add -p: optimize line selection for short hunkspw/add-p-select

If there are fewer than ten changes in a hunk then make spaces
optional when selecting individual lines. This means that for short
hunks one can just type 1-357 to stage lines 1, 2, 3, 5 & 7.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

3 files changed, 32 insertions, 5 deletions

diff --git a/Documentation/git-add.txt b/Documentation/git-add.txt
index 01ff4d7d24..f3c81dfb11 100644
--- a/Documentation/git-add.txt
+++ b/Documentation/git-add.txt
@@ -340,10 +340,11 @@ patch::
 If you press "l" then the hunk will be reprinted with each insertion or
 deletion labelled with a number and you will be prompted to enter which
 lines you wish to select. Individual line numbers should be separated by
-a space or comma, to specify a range of lines use a dash between
-them. If the upper bound of a range of lines is omitted it defaults to
-the last line. To invert the selection prefix it with "-" so "-3-5,8"
-will select everything except lines 3, 4, 5 and 8.
+a space or comma (these can be omitted if there are fewer than ten
+labelled lines), to specify a range of lines use a dash between them. If
+the upper bound of a range of lines is omitted it defaults to the last
+line. To invert the selection prefix it with "-" so "-3-5,8" will select
+everything except lines 3, 4, 5 and 8.
 +
 After deciding the fate for all hunks, if there is any hunk
 that was chosen, the index is updated with the selected hunks.
diff --git a/git-add--interactive.perl b/git-add--interactive.perl
index 8bc0626f0e..86e373a101 100755
--- a/git-add--interactive.perl
+++ b/git-add--interactive.perl
@@ -1082,6 +1082,29 @@ sub check_hunk_label {
 	return 1;
 }
 
+sub split_hunk_selection {
+	local $_;
+	my @fields = @_;
+	my @ret;
+	for (@fields) {
+		while ($_ ne '') {
+			if (/^[0-9]-$/) {
+				push @ret, $_;
+				last;
+			} elsif (/^([0-9](?:-[0-9])?)(.*)/) {
+				push @ret, $1;
+				$_ = $2;
+			} else {
+				error_msg sprintf
+				    __("invalid hunk line '%s'\n"),
+				    substr($_, 0, 1);
+				return ();
+			}
+		}
+	}
+	return @ret;
+}
+
 sub parse_hunk_selection {
 	local $_;
 	my ($hunk, $line) = @_;
@@ -1100,6 +1123,9 @@ sub parse_hunk_selection {
 			}
 		}
 	}
+	if ($max_label < 10) {
+		@fields = split_hunk_selection(@fields) or return undef;
+	}
 	for (@fields) {
 		if (my ($lo, $hi) = /^([0-9]+)-([0-9]*)$/) {
 			if ($hi eq '') {
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index c1703725f2..b842b3b4c5 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -410,7 +410,7 @@ test_expect_success 'setup expected diff' '
 '
 
 test_expect_success 'can reset individual lines of patch' '
-	printf "%s\n" l "-1 3" |
+	printf "%s\n" l -13 |
 	EDITOR=: git reset -p 2>error &&
 	test_must_be_empty error &&
 	git diff --cached HEAD >actual &&