Re: [PATCH] git-add--interactive: manual hunk editing mode

@@ -970,39 +970,15 @@ sub patch_update_file {
 		push @result, @{$mode->{TEXT}};
 	}
 	for (@hunk) {
-		my $text = $_->{TEXT};
-		my ($o_ofs, $o_cnt, $n_ofs, $n_cnt) =
-		    parse_hunk_header($text->[0]);
-
-		if (!$_->{USE}) {
-			# We would have added ($n_cnt - $o_cnt) lines
-			# to the postimage if we were to use this hunk,
-			# but we didn't.  So the line number that the next
-			# hunk starts at would be shifted by that much.
-			$n_lofs -= ($n_cnt - $o_cnt);
-			next;
-		}
-		else {
-			if ($n_lofs) {
-				$n_ofs += $n_lofs;
-				$text->[0] = ("@@ -$o_ofs" .
-					      (($o_cnt != 1)
-					       ? ",$o_cnt" : '') .
-					      " +$n_ofs" .
-					      (($n_cnt != 1)
-					       ? ",$n_cnt" : '') .
-					      " @@\n");
-			}
-			for (@$text) {
-				push @result, $_;
-			}
+		if ($_->{USE}) {
+			push @result, @{$_->{TEXT}};
 		}
 	}
 
 	if (@result) {
 		my $fh;
 
-		open $fh, '| git apply --cached';
+		open $fh, '| git apply --cached --recount';
 		for (@{$head->{TEXT}}, @result) {
 			print $fh $_;
 		}

@@ -682,93 +682,6 @@ sub split_hunk {
 	return @split;
 }
 
-sub find_last_o_ctx {
-	my ($it) = @_;
-	my $text = $it->{TEXT};
-	my ($o_ofs, $o_cnt) = parse_hunk_header($text->[0]);
-	my $i = @{$text};
-	my $last_o_ctx = $o_ofs + $o_cnt;
-	while (0 < --$i) {
-		my $line = $text->[$i];
-		if ($line =~ /^ /) {
-			$last_o_ctx--;
-			next;
-		}
-		last;
-	}
-	return $last_o_ctx;
-}
-
-sub merge_hunk {
-	my ($prev, $this) = @_;
-	my ($o0_ofs, $o0_cnt, $n0_ofs, $n0_cnt) =
-	    parse_hunk_header($prev->{TEXT}[0]);
-	my ($o1_ofs, $o1_cnt, $n1_ofs, $n1_cnt) =
-	    parse_hunk_header($this->{TEXT}[0]);
-
-	my (@line, $i, $ofs, $o_cnt, $n_cnt);
-	$ofs = $o0_ofs;
-	$o_cnt = $n_cnt = 0;
-	for ($i = 1; $i < @{$prev->{TEXT}}; $i++) {
-		my $line = $prev->{TEXT}[$i];
-		if ($line =~ /^\+/) {
-			$n_cnt++;
-			push @line, $line;
-			next;
-		}
-
-		last if ($o1_ofs <= $ofs);
-
-		$o_cnt++;
-		$ofs++;
-		if ($line =~ /^ /) {
-			$n_cnt++;
-		}
-		push @line, $line;
-	}
-
-	for ($i = 1; $i < @{$this->{TEXT}}; $i++) {
-		my $line = $this->{TEXT}[$i];
-		if ($line =~ /^\+/) {
-			$n_cnt++;
-			push @line, $line;
-			next;
-		}
-		$ofs++;
-		$o_cnt++;
-		if ($line =~ /^ /) {
-			$n_cnt++;
-		}
-		push @line, $line;
-	}
-	my $head = ("@@ -$o0_ofs" .
-		    (($o_cnt != 1) ? ",$o_cnt" : '') .
-		    " +$n0_ofs" .
-		    (($n_cnt != 1) ? ",$n_cnt" : '') .
-		    " @@\n");
-	@{$prev->{TEXT}} = ($head, @line);
-}
-
-sub coalesce_overlapping_hunks {
-	my (@in) = @_;
-	my @out = ();
-
-	my ($last_o_ctx);
-
-	for (grep { $_->{USE} } @in) {
-		my $text = $_->{TEXT};
-		my ($o_ofs) = parse_hunk_header($text->[0]);
-		if (defined $last_o_ctx &&
-		    $o_ofs <= $last_o_ctx) {
-			merge_hunk($out[-1], $_);
-		}
-		else {
-			push @out, $_;
-		}
-		$last_o_ctx = find_last_o_ctx($out[-1]);
-	}
-	return @out;
-}
 
 sub help_patch_cmd {
 	print colored $help_color, <<\EOF ;

@@ -962,8 +875,6 @@ sub patch_update_file {
 		}
 	}
 
-	@hunk = coalesce_overlapping_hunks(@hunk);
-
 	my $n_lofs = 0;
 	my @result = ();
 	if ($mode->{USE}) {

@@ -236,6 +236,7 @@ patch::
        k - leave this hunk undecided, see previous undecided hunk
        K - leave this hunk undecided, see previous hunk
        s - split the current hunk into smaller hunks
+       e - manually edit the current hunk
        ? - print help
 +
 After deciding the fate for all hunks, if there is any hunk

@@ -18,6 +18,18 @@ my ($fraginfo_color) =
 	$diff_use_color ? (
 		$repo->get_color('color.diff.frag', 'cyan'),
 	) : ();
+my ($diff_plain_color) =
+	$diff_use_color ? (
+		$repo->get_color('color.diff.plain', ''),
+	) : ();
+my ($diff_old_color) =
+	$diff_use_color ? (
+		$repo->get_color('color.diff.old', 'red'),
+	) : ();
+my ($diff_new_color) =
+	$diff_use_color ? (
+		$repo->get_color('color.diff.new', 'green'),
+	) : ();
 
 my $normal_color = $repo->get_color("", "reset");
 

@@ -683,6 +695,105 @@ sub split_hunk {
 }
 
 
+sub color_diff {
+	return map {
+		colored((/^@/  ? $fraginfo_color :
+			 /^\+/ ? $diff_new_color :
+			 /^-/  ? $diff_old_color :
+			 $diff_plain_color),
+			$_);
+	} @_;
+}
+
+sub edit_hunk_manually {
+	my ($oldtext) = @_;
+
+	my $hunkfile = $repo->repo_path . "/addp-hunk-edit.diff";
+	my $fh;
+	open $fh, '>', $hunkfile
+		or die "failed to open hunk edit file for writing: " . $!;
+	print $fh "# Manual hunk edit mode -- see bottom for a quick guide\n";
+	print $fh @$oldtext;
+	print $fh <<EOF;
+# ---
+# To remove '-' lines, make them ' ' lines (context).
+# To remove '+' lines, delete them.
+# Lines starting with # will be removed.
+#
+# If the patch applies cleanly, the edited hunk will immediately be
+# marked for staging. If it does not apply cleanly, you will be given
+# an opportunity to edit again. If all lines of the hunk are removed,
+# then the edit is aborted and the hunk is left unchanged.
+EOF
+	close $fh;
+
+	my $editor = $ENV{GIT_EDITOR} || $repo->config("core.editor")
+		|| $ENV{VISUAL} || $ENV{EDITOR} || "vi";
+	system('sh', '-c', $editor.' "$@"', $editor, $hunkfile);
+
+	open $fh, '<', $hunkfile
+		or die "failed to open hunk edit file for reading: " . $!;
+	my @newtext = grep { !/^#/ } <$fh>;
+	close $fh;
+	unlink $hunkfile;
+
+	# Abort if nothing remains
+	if (!grep { /\S/ } @newtext) {
+		return undef;
+	}
+
+	# Reinsert the first hunk header if the user accidentally deleted it
+	if ($newtext[0] !~ /^@/) {
+		unshift @newtext, $oldtext->[0];
+	}
+	return \@newtext;
+}
+
+sub diff_applies {
+	my $fh;
+	open $fh, '| git apply --recount --cached --check';
+	for my $h (@_) {
+		print $fh @{$h->{TEXT}};
+	}
+	return close $fh;
+}
+
+sub prompt_yesno {
+	my ($prompt) = @_;
+	while (1) {
+		print colored $prompt_color, $prompt;
+		my $line = <STDIN>;
+		return 0 if $line =~ /^n/i;
+		return 1 if $line =~ /^y/i;
+	}
+}
+
+sub edit_hunk_loop {
+	my ($head, $hunk, $ix) = @_;
+	my $text = $hunk->[$ix]->{TEXT};
+
+	while (1) {
+		$text = edit_hunk_manually($text);
+		if (!defined $text) {
+			return undef;
+		}
+		my $newhunk = { TEXT => $text, USE => 1 };
+		if (diff_applies($head,
+				 @{$hunk}[0..$ix-1],
+				 $newhunk,
+				 @{$hunk}[$ix+1..$#{$hunk}])) {
+			$newhunk->{DISPLAY} = [color_diff(@{$text})];
+			return $newhunk;
+		}
+		else {
+			prompt_yesno(
+				'Your edited hunk does not apply. Edit again '
+				. '(saying "no" discards!) [y/n]? '
+				) or return undef;
+		}
+	}
+}
+
 sub help_patch_cmd {
 	print colored $help_color, <<\EOF ;
 y - stage this hunk

@@ -694,6 +805,7 @@ J - leave this hunk undecided, see next hunk
 k - leave this hunk undecided, see previous undecided hunk
 K - leave this hunk undecided, see previous hunk
 s - split the current hunk into smaller hunks
+e - manually edit the current hunk
 ? - print help
 EOF
 }

@@ -798,6 +910,7 @@ sub patch_update_file {
 		if (hunk_splittable($hunk[$ix]{TEXT})) {
 			$other .= '/s';
 		}
+		$other .= '/e';
 		for (@{$hunk[$ix]{DISPLAY}}) {
 			print;
 		}

@@ -862,6 +975,12 @@ sub patch_update_file {
 				$num = scalar @hunk;
 				next;
 			}
+			elsif ($line =~ /^e/) {
+				my $newhunk = edit_hunk_loop($head, \@hunk, $ix);
+				if (defined $newhunk) {
+					splice @hunk, $ix, 1, $newhunk;
+				}
+			}
 			else {
 				help_patch_cmd($other);
 				next;

@@ -66,6 +66,73 @@ test_expect_success 'revert works (commit)' '
 	grep "unchanged *+3/-0 file" output
 '
 
+cat >expected <<EOF
+EOF
+cat >fake_editor.sh <<EOF
+EOF
+chmod a+x fake_editor.sh
+test_set_editor "$(pwd)/fake_editor.sh"
+test_expect_success 'dummy edit works' '
+	(echo e; echo a) | git add -p &&
+	git diff > diff &&
+	test_cmp expected diff
+'
+
+cat >patch <<EOF
+@@ -1,1 +1,4 @@
+ this
++patch
+-doesn't
+ apply
+EOF
+echo "#!$SHELL_PATH" >fake_editor.sh
+cat >>fake_editor.sh <<\EOF
+mv -f "$1" oldpatch &&
+mv -f patch "$1"
+EOF
+chmod a+x fake_editor.sh
+test_set_editor "$(pwd)/fake_editor.sh"
+test_expect_success 'bad edit rejected' '
+	git reset &&
+	(echo e; echo n; echo d) | git add -p >output &&
+	grep "hunk does not apply" output
+'
+
+cat >patch <<EOF
+this patch
+is garbage
+EOF
+test_expect_success 'garbage edit rejected' '
+	git reset &&
+	(echo e; echo n; echo d) | git add -p >output &&
+	grep "hunk does not apply" output
+'
+
+cat >patch <<EOF
+@@ -1,0 +1,0 @@
+ baseline
++content
++newcontent
++lines
+EOF
+cat >expected <<EOF
+diff --git a/file b/file
+index b5dd6c9..f910ae9 100644
+--- a/file
++++ b/file
+@@ -1,4 +1,4 @@
+ baseline
+ content
+-newcontent
++more
+ lines
+EOF
+test_expect_success 'real edit works' '
+	(echo e; echo n; echo d) | git add -p &&
+	git diff >output &&
+	test_cmp expected output
+'
+
 if test "$(git config --bool core.filemode)" = false
 then
     say 'skipping filemode tests (filesystem does not properly support modes)'