diff --git a/eden/mononoke/mercurial/revlog/revlog/parser.rs b/eden/mononoke/mercurial/revlog/revlog/parser.rs
index d8bf1e2c96..e8ae5e7818 100644
--- a/eden/mononoke/mercurial/revlog/revlog/parser.rs
+++ b/eden/mononoke/mercurial/revlog/revlog/parser.rs
@@ -53,6 +53,7 @@ bitflags! {
 // Per-revision flags
 bitflags! {
     pub struct IdxFlags: u16 {
+        const OCTOPUS_MERGE = 1 << 12;
         const EXTSTORED     = 1 << 13;
         const CENSORED      = 1 << 15;
     }