v2writable: add DEBUG_DIFF env support

This can help us track down some differences during import,
if needed.

1 files changed, 24 insertions, 0 deletions

diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index 8e1363ea..30ca9cec 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -406,6 +406,26 @@ sub import_init {
         $self->{im} = $im;
 }
 
+# XXX experimental
+sub diff ($$$) {
+        my ($mid, $cur, $new) = @_;
+        use File::Temp qw(tempfile);
+        use PublicInbox::Spawn qw(spawn);
+
+        my ($ah, $an) = tempfile('email-cur-XXXXXXXX');
+        print $ah $cur->as_string or die "print: $!";
+        close $ah or die "close: $!";
+        my ($bh, $bn) = tempfile('email-new-XXXXXXXX');
+        print $bh $new->as_string or die "print: $!";
+        close $bh or die "close: $!";
+        my $cmd = [ qw(diff -u), $an, $bn ];
+        print STDERR "# MID conflict <$mid>\n";
+        my $pid = spawn($cmd, undef, { 1 => 2 });
+        defined $pid or die "diff failed to spawn $!";
+        waitpid($pid, 0) == $pid or die "diff did not finish";
+        unlink($an, $bn);
+}
+
 sub lookup_content {
         my ($self, $mime, $mid) = @_;
         my $ibx = $self->{-inbox};
@@ -427,6 +447,10 @@ sub lookup_content {
                         $found = $smsg;
                         return 0; # break out of loop
                 }
+
+                # XXX DEBUG_DIFF is experimental and may be removed
+                diff($mid, $cur, $mime) if $ENV{DEBUG_DIFF};
+
                 1; # continue
         });
         $found;