Add debug check for cache coherency

crates/sui-core/src/execution_cache/writeback_cache.rs

@@ -570,7 +570,32 @@ impl WritebackCache {
     ) -> CacheResult<(SequenceNumber, ObjectEntry)> {
         self.metrics
             .record_cache_request(request_type, "object_by_id");
-        if let Some(entry) = self.cached.object_by_id_cache.get(object_id) {
+        let entry = self.cached.object_by_id_cache.get(object_id);
+
+        if cfg!(debug_assertions) {
+            if let Some(entry) = &entry {
+                // check that cache is coherent
+                let highest = self
+                    .dirty
+                    .objects
+                    .get(object_id)
+                    .and_then(|entry| entry.get_highest().map(|(version, _)| *version))
+                    .or_else(|| {
+                        let object = self.store.get_object(object_id).unwrap();
+                        object.map(|o| o.version())
+                    });
+
+                assert_eq!(
+                    highest,
+                    match &*entry.lock() {
+                        LatestObjectCacheEntry::Object(version, _) => Some(*version),
+                        LatestObjectCacheEntry::NonExistent => None,
+                    }
+                );
+            }
+        }
+
+        if let Some(entry) = entry {
             let entry = entry.lock();
             match &*entry {
                 LatestObjectCacheEntry::Object(latest_version, latest_object) => {