Re: difftool -d symlinks, under what conditions

[John Keeping <john@keeping.me.uk>]

On Tue, Mar 12, 2013 at 12:23:52PM -0700, David Aguilar wrote:
> I don't think we could do this without adding an additional flag
> to trigger this change in behavior (e.g. --null-sha1-for-....?)
> so that existing users are unaffected by the change.
> 
> It feels like forcing the null SHA-1 is heavy-handed, but I
> haven't thought it through enough.
> 
> While this may be a quick way to get this behavior,
> I wonder if there is a better way.
> 
> Does anybody else have any comments/suggestions on how to
> better accomplish this?

How about something like "--symlink-all" where the everything in the
right-hand tree is symlink'd?

Something like this perhaps:

-- >8 --
diff --git a/git-difftool.perl b/git-difftool.perl
index 0a90de4..cab7c45 100755
--- a/git-difftool.perl
+++ b/git-difftool.perl
@@ -85,7 +85,7 @@ sub exit_cleanup
 
 sub setup_dir_diff
 {
-	my ($repo, $workdir, $symlinks) = @_;
+	my ($repo, $workdir, $symlinks, $symlink_all) = @_;
 
 	# Run the diff; exit immediately if no diff found
 	# 'Repository' and 'WorkingCopy' must be explicitly set to insure that
@@ -159,10 +159,10 @@ EOF
 		}
 
 		if ($rmode ne $null_mode) {
-			if ($rsha1 ne $null_sha1) {
-				$rindex .= "$rmode $rsha1\t$dst_path\0";
-			} else {
+			if ($symlink_all or $rsha1 eq $null_sha1) {
 				push(@working_tree, $dst_path);
+			} else {
+				$rindex .= "$rmode $rsha1\t$dst_path\0";
 			}
 		}
 	}
@@ -299,6 +299,7 @@ sub main
 		prompt => undef,
 		symlinks => $^O ne 'cygwin' &&
 				$^O ne 'MSWin32' && $^O ne 'msys',
+		symlink_all => undef,
 		tool_help => undef,
 	);
 	GetOptions('g|gui!' => \$opts{gui},
@@ -308,6 +309,7 @@ sub main
 		'y' => sub { $opts{prompt} = 0; },
 		'symlinks' => \$opts{symlinks},
 		'no-symlinks' => sub { $opts{symlinks} = 0; },
+		'symlink-all' => \$opts{symlink_all},
 		't|tool:s' => \$opts{difftool_cmd},
 		'tool-help' => \$opts{tool_help},
 		'x|extcmd:s' => \$opts{extcmd});
@@ -346,7 +348,7 @@ sub main
 	# will invoke a separate instance of 'git-difftool--helper' for
 	# each file that changed.
 	if (defined($opts{dirdiff})) {
-		dir_diff($opts{extcmd}, $opts{symlinks});
+		dir_diff($opts{extcmd}, $opts{symlinks}, $opts{symlink_all});
 	} else {
 		file_diff($opts{prompt});
 	}
@@ -354,13 +356,13 @@ sub main
 
 sub dir_diff
 {
-	my ($extcmd, $symlinks) = @_;
+	my ($extcmd, $symlinks, $symlink_all) = @_;
 	my $rc;
 	my $error = 0;
 	my $repo = Git->repository();
 	my $workdir = find_worktree($repo);
 	my ($a, $b, $tmpdir, @worktree) =
-		setup_dir_diff($repo, $workdir, $symlinks);
+		setup_dir_diff($repo, $workdir, $symlinks, $symlink_all);
 
 	if (defined($extcmd)) {
 		$rc = system($extcmd, $a, $b);