Merge bitcoin/bitcoin#21090: Default to NODE_WITNESS in nLocalServices

a806647d260132a00cd633160040625c7dd17803 [validation] Always include merkle root in coinbase commitment (Dhruv Mehta)
189128c220190a588500b8e74ee7ae47671b9558 [validation] Set witness script flag with p2sh for blocks (Dhruv Mehta)
ac82b99db77ec843af82dcdf040dfdbc98c8ff26 [p2p] remove redundant NODE_WITNESS checks (Dhruv Mehta)
6f8b198b8256a6703a6f5e592dfa77fa024a7035 [p2p] remove unused segwitheight=-1 option (Dhruv Mehta)
eba5b1cd6460c98e75d0422bd394e12af7f11e4c [test] remove or move tests using `-segwitheight=-1` (Dhruv Mehta)

Pull request description:

  Builds on #21009 and makes progress on remaining items in #17862

  Removing `RewindBlockIndex()` in #21009 allows the following:

  - removal of tests using `segwitheight=-1` in `p2p_segwit.py`.
  - move `test_upgrade_after_activation()` out of `p2p_segwit.py` reducing runtime
  - in turn, that allows us to drop support for `-segwitheight=-1`, which is only supported for that test.
  - that allows us to always set `NODE_WITNESS` in our local services. The only reason we don't do that is to support `-segwitheight=-1`.
  - that in turn allows us to drop all of the `GetLocalServices() & NODE_WITNESS` checks inside `net_processing.cpp`, since our local services would always include `NODE_WITNESS`

ACKs for top commit:
  mzumsande:
    Code-Review ACK a806647d260132a00cd633160040625c7dd17803
  laanwj:
    Code review ACK a806647d260132a00cd633160040625c7dd17803, nice cleanup
  jnewbery:
    utACK a806647d260132a00cd633160040625c7dd17803
  theStack:
    ACK a806647d260132a00cd633160040625c7dd17803

Tree-SHA512: 73e1a69d1d7eca1f5c38558ec6672decd0b60b16c2ef6134df6f6af71bb159e6eea160f9bb5ab0eb6723c6632d29509811e29469d0d87abbe9b69a2890fbc73e

1 files changed, 19 insertions, 26 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index f81c27e8e3..842687e4d6 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1645,13 +1645,8 @@ static unsigned int GetBlockScriptFlags(const CBlockIndex* pindex, const Consens
         pindex->phashBlock == nullptr || // this is a new candidate block, eg from TestBlockValidity()
         *pindex->phashBlock != consensusparams.BIP16Exception) // this block isn't the historical exception
     {
-        flags |= SCRIPT_VERIFY_P2SH;
-    }
-
-    // Enforce WITNESS rules whenever P2SH is in effect (and the segwit
-    // deployment is defined).
-    if (flags & SCRIPT_VERIFY_P2SH && DeploymentEnabled(consensusparams, Consensus::DEPLOYMENT_SEGWIT)) {
-        flags |= SCRIPT_VERIFY_WITNESS;
+        // Enforce WITNESS rules whenever P2SH is in effect
+        flags |= SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS;
     }
 
     // Enforce the DERSIG (BIP66) rule
@@ -3101,25 +3096,23 @@ std::vector<unsigned char> GenerateCoinbaseCommitment(CBlock& block, const CBloc
     std::vector<unsigned char> commitment;
     int commitpos = GetWitnessCommitmentIndex(block);
     std::vector<unsigned char> ret(32, 0x00);
-    if (DeploymentEnabled(consensusParams, Consensus::DEPLOYMENT_SEGWIT)) {
-        if (commitpos == NO_WITNESS_COMMITMENT) {
-            uint256 witnessroot = BlockWitnessMerkleRoot(block, nullptr);
-            CHash256().Write(witnessroot).Write(ret).Finalize(witnessroot);
-            CTxOut out;
-            out.nValue = 0;
-            out.scriptPubKey.resize(MINIMUM_WITNESS_COMMITMENT);
-            out.scriptPubKey[0] = OP_RETURN;
-            out.scriptPubKey[1] = 0x24;
-            out.scriptPubKey[2] = 0xaa;
-            out.scriptPubKey[3] = 0x21;
-            out.scriptPubKey[4] = 0xa9;
-            out.scriptPubKey[5] = 0xed;
-            memcpy(&out.scriptPubKey[6], witnessroot.begin(), 32);
-            commitment = std::vector<unsigned char>(out.scriptPubKey.begin(), out.scriptPubKey.end());
-            CMutableTransaction tx(*block.vtx[0]);
-            tx.vout.push_back(out);
-            block.vtx[0] = MakeTransactionRef(std::move(tx));
-        }
+    if (commitpos == NO_WITNESS_COMMITMENT) {
+        uint256 witnessroot = BlockWitnessMerkleRoot(block, nullptr);
+        CHash256().Write(witnessroot).Write(ret).Finalize(witnessroot);
+        CTxOut out;
+        out.nValue = 0;
+        out.scriptPubKey.resize(MINIMUM_WITNESS_COMMITMENT);
+        out.scriptPubKey[0] = OP_RETURN;
+        out.scriptPubKey[1] = 0x24;
+        out.scriptPubKey[2] = 0xaa;
+        out.scriptPubKey[3] = 0x21;
+        out.scriptPubKey[4] = 0xa9;
+        out.scriptPubKey[5] = 0xed;
+        memcpy(&out.scriptPubKey[6], witnessroot.begin(), 32);
+        commitment = std::vector<unsigned char>(out.scriptPubKey.begin(), out.scriptPubKey.end());
+        CMutableTransaction tx(*block.vtx[0]);
+        tx.vout.push_back(out);
+        block.vtx[0] = MakeTransactionRef(std::move(tx));
     }
     UpdateUncommittedBlockStructures(block, pindexPrev, consensusParams);
     return commitment;