Scala 2.13.4 '-Xlint:strict-unsealed-patmat' compiler flag

[Christewart]

Scala 2.13.4 adds a new compiler flag called

-Xlint:strict-unsealed-patmat

scala/scala#9299

You can see this branch as an example of enabling it

https://github.com/Christewart/bitcoin-s-core/tree/2020-11-26-strict-unsealed-patmat

Currently we have a bunch of errors when enabling this flag

sbt:bitcoin-s> core/compile
[info] Formatting 258 Scala sources...
[info] compiling 258 Scala sources to /home/suredbits/dev/bitcoin-s/core/target/scala-2.13/classes ...
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/api/wallet/db/AddressDb.scala:130:5: match may not be exhaustive.
[error] It would fail on the following input: (x: org.bitcoins.core.hd.HDPath forSome x not in (org.bitcoins.core.hd.LegacyHDPath, org.bitcoins.core.hd.NestedSegWitHDPath, org.bitcoins.core.hd.SegWitHDPath))
[error] path match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/bloom/BloomFilter.scala:233:7: match may not be exhaustive.
[error] It would fail on the following input: (x: Seq[?] forSome x not in Nil)
[error] constantsWithIndex match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/consensus/Merkle.scala:38:5: match may not be exhaustive.
[error] It would fail on the following input: (x: Seq[?] forSome x not in Nil)
[error] transactions match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/consensus/Merkle.scala:60:5: match may not be exhaustive.
[error] It would fail on the following input: (x: Seq[?] forSome x not in Nil)
[error] subTrees match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/p2p/NetworkPayload.scala:205:21: match may not be exhaustive.
[error] It would fail on the following input: (x: Seq[?] forSome x not in Nil)
[error] val hashesStr = hashes match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/protocol/blockchain/PartialMerkleTree.scala:73:11: match may not be exhaustive.
[error] It would fail on the following input: (x: org.bitcoins.core.util.BinaryTree[?] forSome x not in (Empty, org.bitcoins.core.util.Leaf[?], org.bitcoins.core.util.Node[?]))
[error] subTree match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/protocol/blockchain/PartialMerkleTree.scala:124:7: match may not be exhaustive.
[error] It would fail on the following input: (x: org.bitcoins.core.util.BinaryTree[?] forSome x not in (Empty, org.bitcoins.core.util.Leaf[?], org.bitcoins.core.util.Node[?]))
[error] subTree match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/protocol/transaction/InputUtil.scala:51:7: match may not be exhaustive.
[error] It would fail on the following input: (x: Seq[?] forSome x not in Nil)
[error] remaining match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/protocol/transaction/TxUtil.scala:71:7: match may not be exhaustive.
[error] It would fail on the following input: (x: Seq[?] forSome x not in Nil)
[error] remaining match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/serializers/script/ScriptParser.scala:76:25: match may not be exhaustive.
[error] bytes.size match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/util/BinaryTree.scala:11:5: match may not be exhaustive.
[error] It would fail on the following input: (x: org.bitcoins.core.util.BinaryTree[?] forSome x not in (Empty, org.bitcoins.core.util.Leaf[?], org.bitcoins.core.util.Node[?]))
[error] this match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/util/BinaryTree.scala:18:5: match may not be exhaustive.
[error] It would fail on the following input: (x: org.bitcoins.core.util.BinaryTree[?] forSome x not in (Empty, org.bitcoins.core.util.Leaf[?], org.bitcoins.core.util.Node[?]))
[error] this match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/util/BinaryTree.scala:25:5: match may not be exhaustive.
[error] It would fail on the following input: (x: org.bitcoins.core.util.BinaryTree[?] forSome x not in (Empty, org.bitcoins.core.util.Leaf[?], org.bitcoins.core.util.Node[?]))
[error] this match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/util/BinaryTree.scala:41:7: match may not be exhaustive.
[error] It would fail on the following input: (x: org.bitcoins.core.util.BinaryTree[?] forSome x not in (Empty, org.bitcoins.core.util.Leaf[?], org.bitcoins.core.util.Node[?]))
[error] tree match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/util/BinaryTree.scala:62:7: match may not be exhaustive.
[error] It would fail on the following input: (x: org.bitcoins.core.util.BinaryTree[?] forSome x not in (Empty, org.bitcoins.core.util.Leaf[?], org.bitcoins.core.util.Node[?]))
[error] subTree match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/util/BinaryTree.scala:100:5: match may not be exhaustive.
[error] It would fail on the following input: (x: org.bitcoins.core.util.BinaryTree[?] forSome x not in (Empty, org.bitcoins.core.util.Leaf[?], org.bitcoins.core.util.Node[?]))
[error] parentTree match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/util/BinaryTree.scala:115:5: match may not be exhaustive.
[error] It would fail on the following input: (x: org.bitcoins.core.util.BinaryTree[?] forSome x not in (Empty, org.bitcoins.core.util.Leaf[?], org.bitcoins.core.util.Node[?]))
[error] parentTree match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/util/BinaryTree.scala:128:5: match may not be exhaustive.
[error] It would fail on the following input: (x: org.bitcoins.core.util.BinaryTree[?] forSome x not in (Empty, org.bitcoins.core.util.Leaf[?], org.bitcoins.core.util.Node[?]))
[error] parentTree match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/util/BinaryTree.scala:146:7: match may not be exhaustive.
[error] It would fail on the following input: (x: org.bitcoins.core.util.BinaryTree[?] forSome x not in (Empty, org.bitcoins.core.util.Leaf[?], org.bitcoins.core.util.Node[?]))
[error] tree match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/util/BitcoinScriptUtil.scala:191:7: match may not be exhaustive.
[error] It would fail on the following input: (x: Seq[?] forSome x not in Nil)
[error] tokens match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/util/BitcoinScriptUtil.scala:553:7: match may not be exhaustive.
[error] It would fail on the following input: (x: Seq[?] forSome x not in Nil)
[error] remainingSigs match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/wallet/utxo/InputSigningInfo.scala:49:5: match may not be exhaustive.
[error] It would fail on the following input: (x: InputType forSome x not in (org.bitcoins.core.wallet.utxo.P2SHNestedSegwitV0InputInfo, org.bitcoins.core.wallet.utxo.P2SHNonSegwitInputInfo, org.bitcoins.core.wallet.utxo.RawInputInfo, org.bitcoins.core.wallet.utxo.SegwitV0NativeInputInfo, org.bitcoins.core.wallet.utxo.UnassignedSegwitNativeInputInfo))
[error] inputInfo match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/wallet/utxo/InternalAddressTag.scala:86:9: match may not be exhaustive.
[error] It would fail on the following input: (x: org.bitcoins.core.wallet.utxo.AddressTagName forSome x not in (ColdStorageName, DeepColdStorageName, HotStorageName, org.bitcoins.core.wallet.utxo.UnknownAddressTagName))
[error] tagName match {
[error] ^
[error] /home/suredbits/dev/bitcoin-s/core/src/main/scala/org/bitcoins/core/wallet/utxo/InternalAddressTag.scala:84:5: match may not be exhaustive.
[error] It would fail on the following input: (x: org.bitcoins.core.wallet.utxo.AddressTagType forSome x not in (AddressLabelTagType, StorageLocationTagType, org.bitcoins.core.wallet.utxo.UnknownAddressTagType))
[error] tagType match {
[error] ^
[error] 24 errors found
[error] (core / Compile / compileIncremental) Compilation failed
[error] Total time: 51 s, completed Nov 26, 2020, 9:04:56 AM

[Christewart]

I tried some of this on https://github.com/christewart/bitcoin-s-core/tree/2021-06-15-unsealed-pat-mat

but it appears there is some discussion on scala forums that this flag is too strict, and i experienced that too

https://contributors.scala-lang.org/t/trouble-with-2-13-4-exhaustivity-checking-being-too-strict/4817/13