1 files changed, 3 insertions, 1 deletions
diff --git a/lib/PublicInbox/View.pm b/lib/PublicInbox/View.pm
index 47a2046e..35e171b0 100644
--- a/lib/PublicInbox/View.pm
+++ b/lib/PublicInbox/View.pm
@@ -568,7 +568,9 @@ sub add_text_body {
          # always support diff-highlighting, but we can't linkify hunk
          # headers for solver unless some coderepo are configured:
          my $diff;
-        if ($s =~ /^(?:diff|---|\+{3}) /ms) {
+        if ($s =~ /^([ \t]*)(?:diff|---|\+{3}) /ms) {
+                $ctx->{-dpfx} = $1 if $1; # for format-patch --interdiff output
+
                  # diffstat anchors do not link across attachments or messages:
                  $idx[0] = $upfx . $idx[0] if $upfx ne '';
                  $ctx->{-apfx} = join('/', @idx);