Merge #13491: Improve handling of INVALID in IsMine

bb582a5 Add P2WSH destination helper and use it instead of manual hashing (Pieter Wuille)
eaba1c1 Add additional unit tests for invalid IsMine combinations (Pieter Wuille)
e6b9730 Do not expose invalidity from IsMine (Pieter Wuille)

Pull request description:

  This improves the handling of INVALID in IsMine:
  * Extra INVALID conditions were added to `IsMine` (following https://github.com/bitcoin/bitcoin/pull/13142/files#r185349057), but these were untested. Add unit tests for them.
  * In bitcoin/bitcoin#13142 (comment) it was suggested to merge `isInvalid` into the return status. This PR takes a different approach, and removes the `isInvalid` entirely. It was only ever used inside tests, as normal users of IsMine don't care about the reason for non-mine-ness, only whether it is or not. As the unit tests are extensive enough, it seems sufficient to have a black box text (with tests for both compressed and uncompressed keys).

  Some addition code simplification is done as well.

Tree-SHA512: 3267f8846f3fa4e994f57504b155b0e1bbdf13808c4c04dab7c6886c2c0b88716169cee9c5b350513297e0ca2a00812e3401acf30ac9cde5d892f9fb59ad7fef

Author: laanwj

src/rpc/rawtransaction.cpp

@@ -637,9 +637,7 @@ static UniValue decodescript(const JSONRPCRequest& request)
             } else {
                 // Scripts that are not fit for P2WPKH are encoded as P2WSH.
                 // Newer segwit program versions should be considered when then become available.
-                uint256 scriptHash;
-                CSHA256().Write(script.data(), script.size()).Finalize(scriptHash.begin());
-                segwitScr = GetScriptForDestination(WitnessV0ScriptHash(scriptHash));
+                segwitScr = GetScriptForDestination(WitnessV0ScriptHash(script));
             }
             ScriptPubKeyToUniv(segwitScr, sr, true);
             sr.pushKV("p2sh-segwit", EncodeDestination(CScriptID(segwitScr)));

src/script/ismine.cpp

@@ -38,7 +38,7 @@ enum class IsMineResult
     NO = 0,          //! Not ours
     WATCH_ONLY = 1,  //! Included in watch-only balance
     SPENDABLE = 2,   //! Included in all balances
-    INVALID = 3,     //! Not spendable by anyone
+    INVALID = 3,     //! Not spendable by anyone (uncompressed pubkey in segwit, P2SH inside P2SH or witness, witness inside witness)
 };
 
 bool PermitsUncompressed(IsMineSigVersion sigversion)
@@ -173,12 +173,10 @@ IsMineResult IsMineInner(const CKeyStore& keystore, const CScript& scriptPubKey,
 
 } // namespace
 
-isminetype IsMine(const CKeyStore& keystore, const CScript& scriptPubKey, bool& isInvalid)
+isminetype IsMine(const CKeyStore& keystore, const CScript& scriptPubKey)
 {
-    isInvalid = false;
     switch (IsMineInner(keystore, scriptPubKey, IsMineSigVersion::TOP)) {
     case IsMineResult::INVALID:
-        isInvalid = true;
     case IsMineResult::NO:
         return ISMINE_NO;
     case IsMineResult::WATCH_ONLY:
@@ -189,12 +187,6 @@ isminetype IsMine(const CKeyStore& keystore, const CScript& scriptPubKey, bool&
     assert(false);
 }
 
-isminetype IsMine(const CKeyStore& keystore, const CScript& scriptPubKey)
-{
-    bool isInvalid = false;
-    return IsMine(keystore, scriptPubKey, isInvalid);
-}
-
 isminetype IsMine(const CKeyStore& keystore, const CTxDestination& dest)
 {
     CScript script = GetScriptForDestination(dest);

src/script/ismine.h

@@ -24,12 +24,6 @@ enum isminetype
 /** used for bitflags of isminetype */
 typedef uint8_t isminefilter;
 
-/* isInvalid becomes true when the script is found invalid by consensus or policy. This will terminate the recursion
- * and return ISMINE_NO immediately, as an invalid script should never be considered as "mine". This is needed as
- * different SIGVERSION may have different network rules. Currently the only use of isInvalid is indicate uncompressed
- * keys in SigVersion::WITNESS_V0 script, but could also be used in similar cases in the future
- */
-isminetype IsMine(const CKeyStore& keystore, const CScript& scriptPubKey, bool& isInvalid);
 isminetype IsMine(const CKeyStore& keystore, const CScript& scriptPubKey);
 isminetype IsMine(const CKeyStore& keystore, const CTxDestination& dest);
 

src/script/standard.cpp

@@ -5,6 +5,7 @@
 
 #include <script/standard.h>
 
+#include <crypto/sha256.h>
 #include <pubkey.h>
 #include <script/script.h>
 #include <util.h>
@@ -18,6 +19,11 @@ unsigned nMaxDatacarrierBytes = MAX_OP_RETURN_RELAY;
 
 CScriptID::CScriptID(const CScript& in) : uint160(Hash160(in.begin(), in.end())) {}
 
+WitnessV0ScriptHash::WitnessV0ScriptHash(const CScript& in)
+{
+    CSHA256().Write(in.data(), in.size()).Finalize(begin());
+}
+
 const char* GetTxnOutputType(txnouttype t)
 {
     switch (t)
@@ -329,9 +335,7 @@ CScript GetScriptForWitness(const CScript& redeemscript)
             return GetScriptForDestination(WitnessV0KeyHash(vSolutions[0]));
         }
     }
-    uint256 hash;
-    CSHA256().Write(&redeemscript[0], redeemscript.size()).Finalize(hash.begin());
-    return GetScriptForDestination(WitnessV0ScriptHash(hash));
+    return GetScriptForDestination(WitnessV0ScriptHash(redeemscript));
 }
 
 bool IsValidDestination(const CTxDestination& dest) {

src/script/standard.h

@@ -77,6 +77,7 @@ struct WitnessV0ScriptHash : public uint256
 {
     WitnessV0ScriptHash() : uint256() {}
     explicit WitnessV0ScriptHash(const uint256& hash) : uint256(hash) {}
+    explicit WitnessV0ScriptHash(const CScript& script);
     using uint256::uint256;
 };