[PATCH] ssoma-rm: do not commit changes on auto-removal miss

[Eric Wong <e@80x24.org>]

No-op removals should be idempotent, as multiple reporters
may attempt to remove the same message at nearly the same
time.
---
 lib/Ssoma/Git.pm     |  2 +-
 lib/Ssoma/Remover.pm |  4 +++-
 t/remover.t          | 18 ++++++++++++++++++
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/lib/Ssoma/Git.pm b/lib/Ssoma/Git.pm
index 60058df..05fa5a3 100644
--- a/lib/Ssoma/Git.pm
+++ b/lib/Ssoma/Git.pm
@@ -215,7 +215,7 @@ sub cat_blob {
 sub type {
 	my ($self, $obj) = @_;
 	my $cmd = "git cat-file -t $obj";
-	my $str = `$cmd`;
+	my $str = `$cmd 2>/dev/null`;
 	die "$cmd failed: $?\n" if $?;
 	chomp $str;
 	$str;
diff --git a/lib/Ssoma/Remover.pm b/lib/Ssoma/Remover.pm
index 5e5872c..184db1a 100644
--- a/lib/Ssoma/Remover.pm
+++ b/lib/Ssoma/Remover.pm
@@ -30,7 +30,8 @@ sub _remove {
 	my $ref = $self->{ref};
 	my $tip = $git->qx_sha1("git rev-parse $ref^0");
 	my $obj = "$tip:$path";
-	my $type = $git->type($obj);
+	my $type = eval { $git->type($obj) };
+	return unless defined $type;
 	my (@keep, @remove);
 	if ($type eq "tree") { # unlikely
 		$git->each_in_tree($obj, sub {
@@ -50,6 +51,7 @@ sub _remove {
 	} else {
 		die "unhandled type=$type for obj=$obj\n";
 	}
+	return unless @remove;
 
 	my $gii = Ssoma::GitIndexInfo->new;
 	foreach my $rm (@remove) { $gii->remove($rm) }
diff --git a/t/remover.t b/t/remover.t
index 1d74c02..f714aff 100644
--- a/t/remover.t
+++ b/t/remover.t
@@ -82,6 +82,24 @@ EOF
 		$expect--;
 		is(scalar @tree, $expect, "$expect messages left");
 	}
+
+	{
+		local $ENV{GIT_DIR} = $git_dir;
+		my $before = `git rev-parse HEAD^0`;
+		$rm->remove_simple($email);
+		my $after = `git rev-parse HEAD^0`;
+		is($before, $after, 'no commit on no-op removal');
+	}
+
+	{
+		local $ENV{GIT_DIR} = $git_dir;
+		$mda->deliver($email);
+		my $before = `git rev-parse HEAD^0`;
+		$email->body_set('changed');
+		$rm->remove_simple($email);
+		my $after = `git rev-parse HEAD^0`;
+		is($before, $after, 'no commit on no-op removal miss');
+	}
 }
 
 done_testing();
-- 
EW