refactor(jsonrpc): use getHeadBlockNum for parseBlockTag latest resolution, also use longValueExact in eth_getProof block number parsing and clarify the getBlockByNumOrTag comment

Author: 0xbigapple

framework/src/main/java/org/tron/core/services/jsonrpc/JsonRpcApiUtil.java

@@ -526,17 +526,17 @@ public static boolean isBlockTag(String tag) {
         || SAFE_STR.equalsIgnoreCase(tag);
   }
 
+  /**
+   * Parse a block tag (latest, earliest, finalized) to block number.
+   *
+   * <p>Note: for "latest", the returned block number may not yet be available in
+   * blockStore or blockIndexStore due to write ordering. Callers that need the
+   * actual block must handle the not-found case.</p>
+   */
   public static long parseBlockTag(String tag, Wallet wallet)
       throws JsonRpcInvalidParamsException {
     if (LATEST_STR.equalsIgnoreCase(tag)) {
-      // Use getNowBlock() to fetch the latest persisted block directly from blockStore,
-      // avoiding a race with updateDynamicProperties that updates latestBlockHeaderNumber
-      // before the block is written to blockStore/blockIndexStore.
-      Block block = wallet.getNowBlock();
-      if (block == null) {
-        return 0;
-      }
-      return block.getBlockHeader().getRawData().getNumber();
+      return wallet.getHeadBlockNum();
     }
     if (EARLIEST_STR.equalsIgnoreCase(tag)) {
       return 0;

framework/src/main/java/org/tron/core/services/jsonrpc/TronJsonRpcImpl.java

@@ -371,8 +371,8 @@ private Block getBlockByNumOrTag(String blockNumOrTag) throws JsonRpcInvalidPara
     long blockNum;
     if (JsonRpcApiUtil.isBlockTag(blockNumOrTag)) {
       if (LATEST_STR.equalsIgnoreCase(blockNumOrTag)) {
-        // Read the head block directly from blockStore to avoid the window where
-        // getNowBlock() already sees the new head but getBlockByNum() still misses it.
+        // Return the head block directly from blockStore, bypassing blockIndexStore
+        // which may not yet be written when latestBlockHeaderNumber is already updated.
         return wallet.getNowBlock();
       }
       return wallet.getBlockByNum(JsonRpcApiUtil.parseBlockTag(blockNumOrTag, wallet));
@@ -971,7 +971,7 @@ public String getCall(CallArguments transactionCall, Object blockParamObj)
 
         long blockNumber;
         try {
-          blockNumber = ByteArray.hexToBigInteger(blockNumOrTag).longValue();
+          blockNumber = ByteArray.hexToBigInteger(blockNumOrTag).longValueExact();
         } catch (Exception e) {
           throw new JsonRpcInvalidParamsException(BLOCK_NUM_ERROR);
         }