vm: fix blockchain tests crashing

trie: save key-values read from disk in cache

Author: jochem-brouwer

packages/trie/src/checkpointDb.ts

@@ -97,8 +97,14 @@ export class CheckpointDB extends DB {
       }
     }
     // Nothing has been found in cache, look up from disk
-    // TODO: put value in cache if we are a checkpoint.
-    return await super.get(key)
+
+    const value = await super.get(key)
+    if (this.isCheckpoint) {
+      // Since we are a checkpoint, put this value in cache, so future `get` calls will not look the key up again from disk.
+      this.checkpoints[this.checkpoints.length - 1].keyValueMap.set(key.toString('hex'), value)
+    }
+
+    return value
   }
 
   /**

packages/vm/tests/BlockchainTestsRunner.ts

@@ -73,6 +73,10 @@ export default async function runBlockchainTest(options: any, testData: any, t:
     common,
   })
 
+  // Need to await the init promise: in some tests, we do not run the iterator (which awaits the initPromise)
+  // If the initPromise does not finish, the `rawHead` of `blockchain.meta()` is still `undefined`.
+  await blockchain.initPromise
+
   // set up pre-state
   await setupPreConditions(vm.stateManager._trie, testData)