--- a/rust/hg-core/src/revlog/revlog.rs	Tue Apr 19 10:53:58 2022 -0400
+++ b/rust/hg-core/src/revlog/revlog.rs	Thu Mar 31 22:59:19 2022 -0700
@@ -18,7 +18,7 @@
 use crate::errors::HgError;
 use crate::repo::Repo;
 use crate::revlog::Revision;
-use crate::{Node, NULL_REVISION};
+use crate::{requirements, Node, NULL_REVISION};
 
 const REVISION_FLAG_CENSORED: u16 = 1 << 15;
 const REVISION_FLAG_ELLIPSIS: u16 = 1 << 14;
@@ -111,6 +111,12 @@
 
         let nodemap = if index.is_inline() {
             None
+        } else if !repo
+            .requirements()
+            .contains(requirements::NODEMAP_REQUIREMENT)
+        {
+            // If .hg/requires does not opt it, don’t try to open a nodemap
+            None
         } else {
             NodeMapDocket::read_from_file(repo, index_path)?.map(
                 |(docket, data)| {