[PATCH v5 3/4] add -p: allow line selection to be inverted

[Phillip Wood <phillip.wood@talktalk.net>]

From: Phillip Wood <phillip.wood@dunelm.org.uk>

If the list of lines to be selected begins with '-' select all the
lines except the ones listed.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
---
 Documentation/git-add.txt  |  3 ++-
 git-add--interactive.perl  | 19 +++++++++++++++++++
 t/t3701-add-interactive.sh |  2 +-
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/Documentation/git-add.txt b/Documentation/git-add.txt
index 965e192a09..01ff4d7d24 100644
--- a/Documentation/git-add.txt
+++ b/Documentation/git-add.txt
@@ -342,7 +342,8 @@ 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.
+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 7e4daee2fc..63541d0f90 100755
--- a/git-add--interactive.perl
+++ b/git-add--interactive.perl
@@ -1247,8 +1247,21 @@ sub parse_hunk_selection {
 	my ($hunk, $line) = @_;
 	my $lines = $hunk->{LABELS}->{LINES};
 	my $max_label = $#{$lines};
+	my $invert = undef;
 	my %selected;
 	my @fields = split(/[,\s]+/, $line);
+	if (my ($rest) = ($fields[0] =~ /^-(.*)/)) {
+		$invert = 1;
+		if ($rest ne '') {
+			$fields[0] = $rest;
+		} else {
+			shift @fields;
+			unless (@fields) {
+				error_msg __("no lines to invert\n");
+				return undef;
+			}
+		}
+	}
 	for my $f (@fields) {
 		if (my ($lo, $hi) = ($f =~ /^([0-9]+)-([0-9]*)$/)) {
 			if ($hi eq '') {
@@ -1268,6 +1281,12 @@ sub parse_hunk_selection {
 			return undef;
 		}
 	}
+	if ($invert) {
+		my %inverted;
+		undef @inverted{1..$max_label};
+		delete @inverted{keys(%selected)};
+		%selected = %inverted;
+	}
 	return process_hunk_selection($hunk, keys(%selected));
 }
 
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index 1d917ad018..2fd456017f 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -457,7 +457,7 @@ test_expect_success 'setup expected diff' '
 '
 
 test_expect_success 'can reset individual lines of patch' '
-	printf "%s\n" l 4,1,3 |
+	printf "%s\n" l -6,2,5 |
 	EDITOR=: git reset -p 2>error &&
 	test_must_be_empty error &&
 	git diff --cached HEAD >actual &&
-- 
2.18.0