Re: [RFC PATCH] git add -p: new "quit" command at the prompt.

[Jeff King <peff@peff.net>]

On Thu, Apr 16, 2009 at 02:00:27AM -0400, Jeff King wrote:

> > Currently parse_diff_header() returns the mode line into $mode and the
> > main loop treats $mode differently from @hunk, which is an array of hunks
> > parsed by parse_diff().  Treating $mode as a "fake hunk" by unshifting it
> > at the beginning of @hunk array and teaching the main loop minor details
> > such as $mode "fake hunk" cannot be edited nor split, I suspect we _could_
> > unify the two.
>
> Let me see how painful it would be.

Not too painful at all. We can _almost_ get away with a really minimal
"just unshift it" patch, but calling splittable_hunk() generates some
perl warnings (because the hunk lacks @@ lines), and doing a hunk edit
seems to confuse the code (it duplicates the "old mode" line for some
reason). It is not worth trying to fix, though, as editing the mode hunk
is not useful in practice (see the commit message below).

It would also be possible to refactor the header parsing to just pull
the mode lines out as we are parsing the hunks. However, it is probably
not worth the added complexity: you have header lines, then some mode
lines, then some more header lines, then some hunks. So you have to keep
more state around to do a linear parse.

Anyway, I think this is a nice improvement on its own, and it should
make Matthieu's patch a little cleaner.

-- >8 --
Subject: [PATCH] add-interactive: refactor mode hunk handling

The original implementation considered the mode separately
from the rest of the hunks, asking about it outside the main
hunk-selection loop. This patch instead places a mode change
as the first hunk in the loop. This has two advantages:

  1. less duplicated code (since we use the main selection
     loop). This also cleans up an inconsistency, which is
     that the main selection loop separates options with a
     comma, whereas the mode prompt used slashes.

  2. users can now skip the mode change and come back to it,
     search for it (via "/mode"), etc, as they can with other
     hunks.

To facilitate this, each hunk is now marked with a "type".
Mode hunks are not considered for splitting (which would
make no sense, and also confuses the split_hunk function),
nor are they editable. In theory, one could edit the mode
lines and change to an entirely new mode. In practice, there
are only two modes that git cares about (0644 and 0755), so
either you want to move from one to the other or not (and
you can do that by staging or not staging).

Signed-off-by: Jeff King <peff@peff.net>
---
 git-add--interactive.perl |   59 ++++++++++++++++-----------------------------
 1 files changed, 21 insertions(+), 38 deletions(-)

diff --git a/git-add--interactive.perl b/git-add--interactive.perl
index def062a..b895e3b 100755
--- a/git-add--interactive.perl
+++ b/git-add--interactive.perl
@@ -620,11 +620,12 @@ sub parse_diff {
 	if ($diff_use_color) {
 		@colored = run_cmd_pipe(qw(git diff-files -p --color --), $path);
 	}
-	my (@hunk) = { TEXT => [], DISPLAY => [] };
+	my (@hunk) = { TEXT => [], DISPLAY => [], TYPE => 'header' };
 
 	for (my $i = 0; $i < @diff; $i++) {
 		if ($diff[$i] =~ /^@@ /) {
-			push @hunk, { TEXT => [], DISPLAY => [] };
+			push @hunk, { TEXT => [], DISPLAY => [],
+				TYPE => 'hunk' };
 		}
 		push @{$hunk[-1]{TEXT}}, $diff[$i];
 		push @{$hunk[-1]{DISPLAY}},
@@ -636,8 +637,8 @@ sub parse_diff {
 sub parse_diff_header {
 	my $src = shift;
 
-	my $head = { TEXT => [], DISPLAY => [] };
-	my $mode = { TEXT => [], DISPLAY => [] };
+	my $head = { TEXT => [], DISPLAY => [], TYPE => 'header' };
+	my $mode = { TEXT => [], DISPLAY => [], TYPE => 'mode' };
 
 	for (my $i = 0; $i < @{$src->{TEXT}}; $i++) {
 		my $dest = $src->{TEXT}->[$i] =~ /^(old|new) mode (\d+)$/ ?
@@ -684,6 +685,7 @@ sub split_hunk {
 		my $this = +{
 			TEXT => [],
 			DISPLAY => [],
+			TYPE => 'hunk',
 			OLD => $o_ofs,
 			NEW => $n_ofs,
 			OCNT => 0,
@@ -873,7 +875,11 @@ sub edit_hunk_loop {
 		if (!defined $text) {
 			return undef;
 		}
-		my $newhunk = { TEXT => $text, USE => 1 };
+		my $newhunk = {
+			TEXT => $text,
+			TYPE => $hunk->[$ix]->{TYPE},
+			USE => 1
+		};
 		if (diff_applies($head,
 				 @{$hunk}[0..$ix-1],
 				 $newhunk,
@@ -985,32 +991,7 @@ sub patch_update_file {
 	}
 
 	if (@{$mode->{TEXT}}) {
-		while (1) {
-			print @{$mode->{DISPLAY}};
-			print colored $prompt_color,
-				"Stage mode change [y/n/a/d/?]? ";
-			my $line = prompt_single_character;
-			if ($line =~ /^y/i) {
-				$mode->{USE} = 1;
-				last;
-			}
-			elsif ($line =~ /^n/i) {
-				$mode->{USE} = 0;
-				last;
-			}
-			elsif ($line =~ /^a/i) {
-				$_->{USE} = 1 foreach ($mode, @hunk);
-				last;
-			}
-			elsif ($line =~ /^d/i) {
-				$_->{USE} = 0 foreach ($mode, @hunk);
-				last;
-			}
-			else {
-				help_patch_cmd('');
-				next;
-			}
-		}
+		unshift @hunk, $mode;
 	}
 
 	$num = scalar @hunk;
@@ -1054,14 +1035,19 @@ sub patch_update_file {
 		}
 		last if (!$undecided);
 
-		if (hunk_splittable($hunk[$ix]{TEXT})) {
+		if ($hunk[$ix]{TYPE} eq 'hunk' &&
+		    hunk_splittable($hunk[$ix]{TEXT})) {
 			$other .= ',s';
 		}
-		$other .= ',e';
+		if ($hunk[$ix]{TYPE} eq 'hunk') {
+			$other .= ',e';
+		}
 		for (@{$hunk[$ix]{DISPLAY}}) {
 			print;
 		}
-		print colored $prompt_color, "Stage this hunk [y,n,a,d,/$other,?]? ";
+		print colored $prompt_color, 'Stage ',
+		  ($hunk[$ix]{TYPE} eq 'mode' ? 'mode change' : 'this hunk'),
+		  " [y,n,a,d,/$other,?]? ";
 		my $line = prompt_single_character;
 		if ($line) {
 			if ($line =~ /^y/i) {
@@ -1193,7 +1179,7 @@ sub patch_update_file {
 				$num = scalar @hunk;
 				next;
 			}
-			elsif ($line =~ /^e/) {
+			elsif ($other =~ /e/ && $line =~ /^e/) {
 				my $newhunk = edit_hunk_loop($head, \@hunk, $ix);
 				if (defined $newhunk) {
 					splice @hunk, $ix, 1, $newhunk;
@@ -1214,9 +1200,6 @@ sub patch_update_file {
 
 	my $n_lofs = 0;
 	my @result = ();
-	if ($mode->{USE}) {
-		push @result, @{$mode->{TEXT}};
-	}
 	for (@hunk) {
 		if ($_->{USE}) {
 			push @result, @{$_->{TEXT}};
-- 
1.6.3.rc0.157.g02b29.dirty