import: (v2) delete writes the blob into history in subdir

This makes it easier to audit deletes with "git log -p" and
prevents an unstable specification of "content_id" from being
stored in history.

This should be cost-free if done in the same partition (and even
cheaper than before as it introduces no new blobs).  It does
have a higher cost across partitions, but is probably irrelevant
given the typical ham:spam ratio.

3 files changed, 22 insertions, 6 deletions

diff --git a/lib/PublicInbox/Import.pm b/lib/PublicInbox/Import.pm
index e20c6e03..94a49fe6 100644
--- a/lib/PublicInbox/Import.pm
+++ b/lib/PublicInbox/Import.pm
@@ -11,7 +11,6 @@ use Fcntl qw(:flock :DEFAULT);
 use PublicInbox::Spawn qw(spawn);
 use PublicInbox::MID qw(mid_mime mid2path);
 use PublicInbox::Address;
-use PublicInbox::ContentId qw(content_id);
 use PublicInbox::MsgTime qw(msg_timestamp);
 
 sub new {
@@ -163,7 +162,6 @@ sub get_mark {
 # ('MISMATCH', Email::MIME) on mismatch
 # (:MARK, Email::MIME) on success
 #
-# For v2 inboxes, the content_id is returned instead of the msg
 # v2 callers should check with Xapian before calling this as
 # it is not idempotent.
 sub remove {
@@ -179,10 +177,17 @@ sub remove {
                 ($err, $cur) = check_remove_v1($r, $w, $tip, $path, $mime);
                 return ($err, $cur) if $err;
         } else {
-                $cur = content_id($mime);
-                my $len = length($cur);
+                my $sref;
+                if (ref($mime) eq 'SCALAR') { # optimization used by V2Writable
+                        $sref = $mime;
+                } else { # XXX should not be necessary:
+                        my $str = $mime->as_string;
+                        $sref = \$str;
+                }
+                my $len = length($$sref);
                 $blob = $self->{mark}++;
-                print $w "blob\nmark :$blob\ndata $len\n$cur\n" or wfail;
+                print $w "blob\nmark :$blob\ndata $len\n",
+                        $$sref, "\n" or wfail;
         }
 
         my $ref = $self->{ref};
diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index 656f0693..fd9bf615 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -220,6 +220,7 @@ sub remove {
                                 warn "broken smsg for $mid\n";
                                 return 1; # continue
                         }
+                        my $orig = $$msg;
                         my $cur = PublicInbox::MIME->new($msg);
                         if (content_id($cur) eq $cid) {
                                 $mm->num_delete($smsg->num);
@@ -227,7 +228,8 @@ sub remove {
                                 # no bugs in our deduplication code:
                                 $removed = $smsg;
                                 $removed->{mime} = $cur;
-                                $im->remove($cur, $cmt_msg);
+                                $im->remove(\$orig, $cmt_msg);
+                                $orig = undef;
                                 $removed->num; # memoize this for callers
 
                                 my $oid = $smsg->{blob};
diff --git a/t/v2writable.t b/t/v2writable.t
index 6e37b722..a5c982e9 100644
--- a/t/v2writable.t
+++ b/t/v2writable.t
@@ -191,6 +191,7 @@ EOF
 {
         local $ENV{NPROC} = 2;
         my @before = $git0->qx(qw(log --pretty=oneline));
+        my $before = $git0->qx(qw(log --pretty=raw --raw -r --no-abbrev));
         $im = PublicInbox::V2Writable->new($ibx, 1);
         is($im->{partitions}, 1, 'detected single partition from previous');
         my $smsg = $im->remove($mime, 'test removal');
@@ -207,6 +208,14 @@ EOF
         my @found = ();
         $srch->each_smsg_by_mid($smsg->mid, sub { push @found, @_; 1 });
         is(scalar(@found), 0, 'no longer found in Xapian skeleton');
+
+        my $after = $git0->qx(qw(log -1 --pretty=raw --raw -r --no-abbrev));
+        if ($after =~ m!( [a-f0-9]+ )A\td$!) {
+                my $oid = $1;
+                ok(index($before, $oid) > 0, 'no new blob introduced');
+        } else {
+                fail('failed to extract blob from log output');
+        }
 }
 
 done_testing();