[KAIZEN] Turn some warnings into errors (#1081)

* [KAIZEN] Turn some warnings into errors

Print summaries for the remaining ones

* [KAIZEN] Fix formatting

* [KAIZEN] Full warnings flag

* [KAIZEN] No errors in nix build

* [KAIZEN] Refactor build.sbt

Retain old settings for Compile/doc (otherwise derivation build fails
in buildkite)

* [KAIZEN] Split -W:conf into multiple lines

.

Author: lukasz-golebiewski

build.sbt

@@ -44,6 +44,35 @@ val `scala-2.12` = "2.12.13"
 val `scala-2.13` = "2.13.6"
 val supportedScalaVersions = List(`scala-2.12`, `scala-2.13`)
 
+val baseScalacOptions = Seq(
+  "-unchecked",
+  "-deprecation",
+  "-feature",
+  "-Ywarn-unused",
+  "-Xlint",
+  "-encoding",
+  "utf-8"
+)
+
+// https://www.scala-lang.org/2021/01/12/configuring-and-suppressing-warnings.html
+// cat={warning-name}:ws prints a summary with the number of warnings of the given type
+// any:e turns all remaining warnings into errors
+val fatalWarnings = Seq(
+  if (sys.env.get("MANTIS_FULL_WARNS").contains("true")) {
+    "-Wconf:any:w"
+  }
+  else {
+    "-Wconf:" ++ Seq(
+      // Let's turn those gradually into errors:
+      "cat=deprecation:ws",
+      "cat=lint-package-object-classes:ws",
+      "cat=unused:ws",
+      "cat=lint-infer-any:ws",
+      "cat=lint-byname-implicit:ws",
+      "cat=other-match-analysis:ws",
+      "any:e").mkString(",")
+  }) ++ Seq("-Ypatmat-exhaust-depth", "off")
+
 def commonSettings(projectName: String): Seq[sbt.Def.Setting[_]] = Seq(
   name := projectName,
   organization := "io.iohk",
@@ -59,23 +88,15 @@ def commonSettings(projectName: String): Seq[sbt.Def.Setting[_]] = Seq(
   resolvers += "Sonatype OSS Snapshots".at("https://oss.sonatype.org/content/repositories/snapshots"),
   (Test / testOptions) += Tests
     .Argument(TestFrameworks.ScalaTest, "-l", "EthashMinerSpec"), // miner tests disabled by default,
-  scalacOptions := Seq(
-    "-unchecked",
-    "-deprecation",
-    "-feature",
-    //    "-Xfatal-warnings", // disabled until unused are removed
-    "-Ywarn-unused",
-    "-Xlint",
-    "-encoding",
-    "utf-8"
-  ),
+  scalacOptions := baseScalacOptions ++ fatalWarnings,
   scalacOptions ++= (if (mantisDev) Seq.empty else compilerOptimizationsForProd),
   (Compile / console / scalacOptions) ~= (_.filterNot(
     Set(
       "-Ywarn-unused-import",
       "-Xfatal-warnings"
     )
   )),
+  (Compile / doc / scalacOptions) := baseScalacOptions,
   scalacOptions ~= (options => if (mantisDev) options.filterNot(_ == "-Xfatal-warnings") else options),
   Test / parallelExecution := true,
   (Test / testOptions) += Tests.Argument("-oDG"),

src/it/scala/io/iohk/ethereum/txExecTest/util/DumpChainApp.scala

@@ -119,7 +119,11 @@ object DumpChainApp
       override val forkResolverOpt: Option[ForkResolver] = DumpChainApp.forkResolverOpt
       override val nodeStatusHolder: AtomicReference[NodeStatus] = DumpChainApp.nodeStatusHolder
       override val peerConfiguration: PeerConfiguration = peerConfig
+      // FIXME: Selecting value blockchain from object DumpChainApp, which extends scala.DelayedInit, is likely to yield an uninitialized value
+      @annotation.nowarn
       override val blockchain: Blockchain = DumpChainApp.blockchain
+      // FIXME: Selecting value blockchainReader from object DumpChainApp, which extends scala.DelayedInit, is likely to yield an uninitialized value
+      @annotation.nowarn
       override val blockchainReader: BlockchainReader = DumpChainApp.blockchainReader
       override val appStateStorage: AppStateStorage = storagesInstance.storages.appStateStorage
       override val blockchainConfig: BlockchainConfig = Config.blockchains.blockchainConfig

src/main/scala/io/iohk/ethereum/blockchain/sync/fast/SyncStateScheduler.scala

@@ -407,11 +407,16 @@ object SyncStateScheduler {
             // needs to be provided
             go(
               currentRequests - parent,
-              currentBatch + (parent -> (parentRequest.resolvedData.getOrElse(
-                throw new IllegalStateException(
-                  s"Critical error. Parent ${parentRequest.nodeHash} without resolved data"
+              currentBatch + (parent -> (
+                (
+                  parentRequest.resolvedData.getOrElse(
+                    throw new IllegalStateException(
+                      s"Critical error. Parent ${parentRequest.nodeHash} without resolved data"
+                    )
+                  ),
+                  parentRequest.requestType
                 )
-              ), parentRequest.requestType)),
+              )),
               parentsToCheck.tail ++ parentRequest.parents
             )
           } else {
@@ -424,7 +429,7 @@ object SyncStateScheduler {
         }
 
       val newActive = activeRequest - request.nodeHash
-      val newMemBatch = memBatch + (request.nodeHash -> (request.resolvedData.get, request.requestType))
+      val newMemBatch = memBatch + (request.nodeHash -> ((request.resolvedData.get, request.requestType)))
 
       val (newRequests, newBatch) = go(newActive, newMemBatch, request.parents)
       copy(activeRequest = newRequests, memBatch = newBatch)

src/main/scala/io/iohk/ethereum/db/storage/ReferenceCountNodeStorage.scala

@@ -82,7 +82,7 @@ class ReferenceCountNodeStorage(nodeStorage: NodesStorage, bn: BigInt) extends N
           StoredNode.withoutReferences(nodeEncoded) -> StoredNodeSnapshot(nodeKey, None)
         ) // if it's new, return an empty stored node
 
-      storedNodes + (nodeKey -> (storedNode.incrementReferences(1, blockNumber), snapshot))
+      storedNodes + (nodeKey -> ((storedNode.incrementReferences(1, blockNumber), snapshot)))
     }
 
   private def prepareRemovalChanges(
@@ -94,7 +94,7 @@ class ReferenceCountNodeStorage(nodeStorage: NodesStorage, bn: BigInt) extends N
       val maybeStoredNode: Option[(StoredNode, StoredNodeSnapshot)] = getFromChangesOrStorage(nodeKey, storedNodes)
 
       maybeStoredNode.fold(storedNodes) { case (storedNode, snapshot) =>
-        storedNodes + (nodeKey -> (storedNode.decrementReferences(1, blockNumber), snapshot))
+        storedNodes + (nodeKey -> ((storedNode.decrementReferences(1, blockNumber), snapshot)))
       }
     }
 

src/main/scala/io/iohk/ethereum/domain/BlockchainWriter.scala

@@ -93,7 +93,7 @@ class BlockchainWriter(
       BestBlockLatestCheckpointNumbers(number, latestCheckpointNumber)
     )
 
-  private def persistBestBlocksData(): Unit = {
+  private def persistBestBlocksData: () => Unit = () => {
     val currentBestBlockNumber = blockchainMetadata.bestKnownBlockAndLatestCheckpoint.get().bestBlockNumber
     val currentBestCheckpointNumber = blockchainMetadata.bestKnownBlockAndLatestCheckpoint.get().latestCheckpointNumber
     log.debug(

src/main/scala/io/iohk/ethereum/faucet/jsonrpc/FaucetBuilder.scala

@@ -100,7 +100,7 @@ trait FaucetJsonRpcHttpServerBuilder {
 trait ShutdownHookBuilder {
   self: ActorSystemBuilder with FaucetConfigBuilder with Logger =>
 
-  def shutdown(): Unit =
+  def shutdown: () => Unit = () =>
     Await.ready(
       system
         .terminate()

src/main/scala/io/iohk/ethereum/jsonrpc/serialization/JsonEncoder.scala

@@ -10,6 +10,7 @@ import org.json4s.JValue
 
 import io.iohk.ethereum.jsonrpc.JsonMethodsImplicits
 
+@FunctionalInterface
 trait JsonEncoder[T] {
   def encodeJson(t: T): JValue
 }

src/main/scala/io/iohk/ethereum/ledger/StxLedger.scala

@@ -84,7 +84,7 @@ object StxLedger {
     * @return minimal value for which provided function do not return error
     */
   @tailrec
-  private[ledger] def binaryChop[Error](min: BigInt, max: BigInt)(f: BigInt => Option[Error]): BigInt = {
+  private[ledger] def binaryChop[Err](min: BigInt, max: BigInt)(f: BigInt => Option[Err]): BigInt = {
     assert(min <= max)
 
     if (min == max)

src/main/scala/io/iohk/ethereum/nodebuilder/NodeBuilder.scala

@@ -804,7 +804,7 @@ trait PortForwardingBuilder {
 
 trait ShutdownHookBuilder {
   self: Logger =>
-  def shutdown(): Unit = {
+  def shutdown: () => Unit = () => {
     /* No default behaviour during shutdown. */
   }
 

src/main/scala/io/iohk/ethereum/nodebuilder/StdNode.scala

@@ -106,7 +106,7 @@ abstract class BaseNode extends Node {
       "PeriodicDBConsistencyCheck"
     )
 
-  override def shutdown(): Unit = {
+  override def shutdown: () => Unit = () => {
     def tryAndLogFailure(f: () => Any): Unit = Try(f()) match {
       case Failure(e) => log.warn("Error while shutting down...", e)
       case Success(_) =>

src/test/scala/io/iohk/ethereum/blockchain/sync/SyncControllerSpec.scala

@@ -621,7 +621,6 @@ class SyncControllerSpec
             this
 
           case SendMessage(msg: GetReceiptsEnc, peer) if !onlyPivot =>
-            msg.underlyingMsg
             if (failedReceiptsTries > 0) {
               sender ! MessageFromPeer(Receipts(Seq()), peer)
               this.copy(failedReceiptsTries = failedReceiptsTries - 1)
@@ -632,7 +631,6 @@ class SyncControllerSpec
             }
 
           case SendMessage(msg: GetBlockBodiesEnc, peer) if !onlyPivot =>
-            msg.underlyingMsg
             if (failedBodiesTries > 0) {
               sender ! MessageFromPeer(BlockBodies(Seq()), peer)
               this.copy(failedBodiesTries = failedBodiesTries - 1)
@@ -644,7 +642,6 @@ class SyncControllerSpec
 
           case SendMessage(msg: GetNodeDataEnc, peer) if !onlyPivot =>
             stateDownloadStarted = true
-            msg.underlyingMsg
             if (!failedNodeRequest) {
               sender ! MessageFromPeer(NodeData(Seq(defaultStateMptLeafWithAccount)), peer)
             }