Keep PendingComponents in da_checker during import_block

beacon_node/beacon_chain/src/beacon_chain.rs

@@ -3328,6 +3328,20 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
                 "payload_verification_handle",
             )
             .await??;
+
+        // Remove block components from da_checker AFTER completing block import. Then we can assert
+        // the following invariant:
+        // > A valid unfinalized block is either in fork-choice or da_checker.
+        //
+        // If we remove the block when it becomes available, there's some time window during
+        // `import_block` where the block is nowhere. Consumers of the da_checker can handle the
+        // extend time a block may exist in the da_checker.
+        //
+        // If `import_block` errors (only errors with internal errors), the pending components will
+        // be pruned on data_availability_checker maintenance as finality advances.
+        self.data_availability_checker
+            .remove_pending_components(block_root);
+
         Ok(AvailabilityProcessingStatus::Imported(block_root))
     }
 

beacon_node/beacon_chain/src/data_availability_checker.rs

@@ -164,6 +164,11 @@ impl<T: BeaconChainTypes> DataAvailabilityChecker<T> {
             .put_pending_executed_block(executed_block)
     }
 
+    pub fn remove_pending_components(&self, block_root: Hash256) {
+        self.availability_cache
+            .remove_pending_components(block_root)
+    }
+
     /// Verifies kzg commitments for an RpcBlock, returns a `MaybeAvailableBlock` that may
     /// include the fully available block.
     ///

beacon_node/beacon_chain/src/data_availability_checker/overflow_lru_cache.rs

@@ -498,6 +498,21 @@ impl<T: BeaconChainTypes> Critical<T> {
         }
     }
 
+    /// Removes and returns the pending_components corresponding to
+    /// the `block_root` or `None` if it does not exist
+    pub fn remove_pending_components(&mut self, block_root: Hash256) {
+        match self.in_memory.pop_entry(&block_root) {
+            Some { .. } => {}
+            None => {
+                // not in memory, is it in the store?
+                // We don't need to remove the data from the store as we have removed it from
+                // `store_keys` so we won't go looking for it on disk. The maintenance thread
+                // will remove it from disk the next time it runs.
+                self.store_keys.remove(&block_root);
+            }
+        }
+    }
+
     /// Returns the number of pending component entries in memory.
     pub fn num_blocks(&self) -> usize {
         self.in_memory.len()
@@ -607,6 +622,11 @@ impl<T: BeaconChainTypes> OverflowLRUCache<T> {
         pending_components.merge_blobs(fixed_blobs);
 
         if pending_components.is_available() {
+            write_lock.put_pending_components(
+                block_root,
+                pending_components.clone(),
+                &self.overflow_store,
+            )?;
             // No need to hold the write lock anymore
             drop(write_lock);
             pending_components.make_available(|diet_block| {
@@ -646,6 +666,11 @@ impl<T: BeaconChainTypes> OverflowLRUCache<T> {
 
         // Check if we have all components and entire set is consistent.
         if pending_components.is_available() {
+            write_lock.put_pending_components(
+                block_root,
+                pending_components.clone(),
+                &self.overflow_store,
+            )?;
             // No need to hold the write lock anymore
             drop(write_lock);
             pending_components.make_available(|diet_block| {
@@ -661,6 +686,10 @@ impl<T: BeaconChainTypes> OverflowLRUCache<T> {
         }
     }
 
+    pub fn remove_pending_components(&self, block_root: Hash256) {
+        self.critical.write().remove_pending_components(block_root);
+    }
+
     /// write all in memory objects to disk
     pub fn write_all_to_disk(&self) -> Result<(), AvailabilityCheckError> {
         let maintenance_lock = self.maintenance_lock.lock();
@@ -1195,10 +1224,17 @@ mod test {
                 matches!(availability, Availability::Available(_)),
                 "block doesn't have blobs, should be available"
             );
+            assert_eq!(
+                cache.critical.read().in_memory.len(),
+                1,
+                "cache should still have block as it hasn't been imported yet"
+            );
+            // remove the blob to simulate successful import
+            cache.remove_pending_components(root);
             assert_eq!(
                 cache.critical.read().in_memory.len(),
                 0,
-                "cache should be empty because we don't have blobs"
+                "cache should be empty now that block has been imported"
             );
         } else {
             assert!(
@@ -1263,6 +1299,12 @@ mod test {
             "block should be available: {:?}",
             availability
         );
+        assert!(
+            cache.critical.read().in_memory.len() == 1,
+            "cache should still have available block until import"
+        );
+        // remove the blob to simulate successful import
+        cache.remove_pending_components(root);
         assert!(
             cache.critical.read().in_memory.is_empty(),
             "cache should be empty now that all components available"
@@ -1378,6 +1420,8 @@ mod test {
                 .expect("should put blob");
             if blob_index == expected_blobs - 1 {
                 assert!(matches!(availability, Availability::Available(_)));
+                // remove the block from the cache to simulate import
+                cache.remove_pending_components(roots[0]);
             } else {
                 // the first block should be brought back into memory
                 assert!(