fixes `importRlpBlocks` in conf_utils.nim

now we are importing block one by one to satisfy
some of hive test cases.

we also catch exception instead of letting it terminate the
process.

nimbus/conf_utils.nim

@@ -19,32 +19,30 @@ type
   EthHeader = object
     header: BlockHeader
 
-proc importRlpBlock*(importFile: string, chainDB: BasechainDB) =
+proc importRlpBlock*(importFile: string, chainDB: BasechainDB): bool =
   let res = io2.readAllBytes(importFile)
   if res.isErr:
     error "failed to import", fileName = importFile
-    quit(QuitFailure)
+    return false
 
   var chain = newChain(chainDB)
   # the encoded rlp can contains one or more blocks
   var rlp = rlpFromBytes(res.get)
-
-  # separate the header and the body
-  # TODO: probably we need to put it in one struct
-  var headers: seq[BlockHeader]
-  var bodies : seq[BlockBody]
   let head = chainDB.getCanonicalHead()
 
+  try:
     while true:
       let header = rlp.read(EthHeader).header
       let body = rlp.readRecordType(BlockBody, false)
       if header.blockNumber > head.blockNumber:
-      headers.add header
-      bodies.add body
-    if not rlp.hasData:
-      break
-
-  let valid = chain.persistBlocks(headers, bodies)
+        let valid = chain.persistBlocks([header], [body])
         if valid == ValidationResult.Error:
           error "failed to import rlp encoded blocks", fileName = importFile
-    quit(QuitFailure)
+          return false
+      if not rlp.hasData:
+        break
+  except CatchableError as e:
+    error "rlp error", fileName = importFile, msg = e.msg, exception = e.name
+    return false
+
+  return true

nimbus/nimbus.nim

@@ -60,7 +60,10 @@ proc start(nimbus: NimbusNode) =
     doAssert(canonicalHeadHashKey().toOpenArray in trieDB)
 
   if conf.importFile.len > 0:
-    importRlpBlock(conf.importFile, chainDB)
+    # success or not, we quit after importing blocks
+    if not importRlpBlock(conf.importFile, chainDB):
+      quit(QuitFailure)
+    else:
       quit(QuitSuccess)
 
   let res = conf.loadKeystoreFiles()