Flat state transition across forks (#4120)

* Update src

* Update tests

* Update spec tests

* Fix Lodestar src

* Fix type issues

* Fix perf test types

* Review PR

* Remove un-used import

* Don't check state root in computeNewStateRoot

* Rename slashValidator

packages/beacon-state-transition/package.json

@@ -17,17 +17,14 @@
     ".": {
       "import": "./lib/index.js"
     },
-    "./allForks": {
-      "import": "./lib/allForks/index.js"
+    "./block": {
+      "import": "./lib/block/index.js"
     },
-    "./phase0": {
-      "import": "./lib/phase0/index.js"
+    "./epoch": {
+      "import": "./lib/epoch/index.js"
     },
-    "./altair": {
-      "import": "./lib/altair/index.js"
-    },
-    "./bellatrix": {
-      "import": "./lib/bellatrix/index.js"
+    "./slot": {
+      "import": "./lib/slot/index.js"
     }
   },
   "typesVersions": {

packages/beacon-state-transition/src/block/index.ts

@@ -0,0 +1,47 @@
+import {ForkSeq} from "@chainsafe/lodestar-params";
+import {allForks, altair, bellatrix} from "@chainsafe/lodestar-types";
+import {ExecutionEngine} from "../util/executionEngine.js";
+import {isExecutionEnabled} from "../util/bellatrix.js";
+import {CachedBeaconStateAllForks, CachedBeaconStateBellatrix} from "../types.js";
+import {processExecutionPayload} from "./processExecutionPayload.js";
+import {processSyncAggregate} from "./processSyncCommittee.js";
+import {processBlockHeader} from "./processBlockHeader.js";
+import {processEth1Data} from "./processEth1Data.js";
+import {processOperations} from "./processOperations.js";
+import {processRandao} from "./processRandao.js";
+
+// Spec tests
+export {processBlockHeader, processExecutionPayload, processRandao, processEth1Data, processSyncAggregate};
+export * from "./processOperations.js";
+
+export * from "./initiateValidatorExit.js";
+export * from "./isValidIndexedAttestation.js";
+
+export function processBlock(
+  fork: ForkSeq,
+  state: CachedBeaconStateAllForks,
+  block: allForks.BeaconBlock,
+  verifySignatures = true,
+  executionEngine: ExecutionEngine | null
+): void {
+  processBlockHeader(state, block);
+
+  // The call to the process_execution_payload must happen before the call to the process_randao as the former depends
+  // on the randao_mix computed with the reveal of the previous block.
+  if (fork >= ForkSeq.bellatrix) {
+    if (isExecutionEnabled(state as CachedBeaconStateBellatrix, (block as bellatrix.BeaconBlock).body)) {
+      processExecutionPayload(
+        state as CachedBeaconStateBellatrix,
+        (block as bellatrix.BeaconBlock).body.executionPayload,
+        executionEngine
+      );
+    }
+  }
+
+  processRandao(state, block, verifySignatures);
+  processEth1Data(state, block.body.eth1Data);
+  processOperations(fork, state, block.body, verifySignatures);
+  if (fork >= ForkSeq.altair) {
+    processSyncAggregate(state, block as altair.BeaconBlock, verifySignatures);
+  }
+}