diff --git a/rust/hg-core/src/discovery.rs b/rust/hg-core/src/discovery.rs
--- a/rust/hg-core/src/discovery.rs
+++ b/rust/hg-core/src/discovery.rs
@@ -563,13 +563,8 @@
         &mut self,
         size: usize,
     ) -> Result<(HashSet<Revision>, usize), GraphError> {
-        {
-            // we don't want to compute children_cache before this
-            // but doing it after extracting self.undecided takes a mutable
-            // ref to self while a shareable one is still active.
-            if self.undecided.len() <= size {
-                return Ok((self.undecided.clone(), size));
-            }
+        if self.undecided.len() <= size {
+            return Ok((self.undecided.clone(), size));
         }
 
         self.ensure_children_cache()?;