lib/PublicInbox/Import.pm     | 31 ++++++++++++++++++++++++-------
 lib/PublicInbox/V2Writable.pm |  3 +--

diff --git a/lib/PublicInbox/Import.pm b/lib/PublicInbox/Import.pm
index 5d116a1c7207b9ea4c0b1f74b0a10ecba46f7e3c..6824faca21dc3205ecd12be9899cb1e14f0e3834 100644
--- a/lib/PublicInbox/Import.pm
+++ b/lib/PublicInbox/Import.pm
@@ -203,7 +203,7 @@
 	my ($r, $w) = $self->gfi_start;
 	my $tip = $self->{tip};
 	if ($path_type eq '2/38') {
-		$path = mid2path(mid_mime($mime));
+		$path = mid2path(v1_mid0($mime));
 		($err, $cur) = check_remove_v1($r, $w, $tip, $path, $mime);
 		return ($err, $cur) if $err;
 	} else {
@@ -296,6 +296,28 @@ 	$mime->header_set($_) for qw(bytes lines content-length status);
 	$mime->header_set($_) for @PublicInbox::MDA::BAD_HEADERS;
 }
 
+# used by V2Writable, too
+sub prepend_mid ($$) {
+	my ($hdr, $mid0) = @_;
+	# @cur is likely empty if we need to call this sub, but it could
+	# have random unparseable crap which we'll preserve, too.
+	my @cur = $hdr->header_raw('Message-Id');
+	$hdr->header_set('Message-Id', "<$mid0>", @cur);
+}
+
+sub v1_mid0 ($) {
+	my ($mime) = @_;
+	my $hdr = $mime->header_obj;
+	my $mids = mids($hdr);
+
+	if (!scalar(@$mids)) { # spam often has no Message-Id
+		my $mid0 = digest2mid(content_digest($mime));
+		prepend_mid($hdr, $mid0);
+		return $mid0;
+	}
+	$mids->[0];
+}
+
 # returns undef on duplicate
 # returns the :MARK of the most recent commit
 sub add {
@@ -313,12 +335,7 @@ 	my $path_type = $self->{path_type};
 
 	my $path;
 	if ($path_type eq '2/38') {
-		my $mids = mids($mime->header_obj);
-		if (!scalar(@$mids)) {
-			my $dig = content_digest($mime);
-			@$mids = (digest2mid($dig));
-		}
-		$path = mid2path($mids->[0]);
+		$path = mid2path(v1_mid0($mime));
 	} else { # v2 layout, one file:
 		$path = 'm';
 	}
diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index 20c27363c3bb55290ef8a1b6c98144f0621e4f4d..b04e6fbfe892dc1227b43c119f93713f38008a86 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -173,8 +173,7 @@ 			warn "using random Message-ID <$$mid0> as fallback\n";
 			$num = $self->{skel}->{mm}->mid_insert($$mid0);
 		}
 	}
-	my @cur = $hdr->header_raw('Message-Id');
-	$hdr->header_set('Message-Id', "<$$mid0>", @cur);
+	PublicInbox::Import::prepend_mid($hdr, $$mid0);
 	$num;
 }