Merge #21377: Speedy trial support for versionbits

ffe33dfbd4c3b11e3475b022b6c1dd077613de79 chainparams: drop versionbits threshold to 90% for mainnnet and signet (Anthony Towns)
f054f6bcd2c2ce5fea84cf8681013f85a444e7ea versionbits: simplify state transitions (Anthony Towns)
55ac5f568a3b73d6f1ef4654617fb76e8bcbccdf versionbits: Add explicit NEVER_ACTIVE deployments (Anthony Towns)
dd07e6da48040dc7eae46bc7941db48d98a669fd fuzz: test versionbits delayed activation (Anthony Towns)
dd85d5411c1702c8ae259610fe55050ba212e21e tests: test versionbits delayed activation (Anthony Towns)
73d4a706393e6dbd6b6d6b6428f8d3233ac0a2d8 versionbits: Add support for delayed activation (Anthony Towns)
9e6b65f6fa205eee5c3b99343988adcb8d320460 tests: clean up versionbits test (Anthony Towns)
593274445004506c921d5d851361aefb3434d744 tests: test ComputeBlockVersion for all deployments (Anthony Towns)
63879f0a4760c0c0f784029849cb5d21ee088abb tests: pull ComputeBlockVersion test into its own function (Anthony Towns)

Pull request description:

  BIP9-based implementation of "speedy trial" activation specification, see https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-March/018583.html

  Edge cases are tested by fuzzing added in #21380.

ACKs for top commit:
  instagibbs:
    tACK https://github.com/bitcoin/bitcoin/pull/21377/commits/ffe33dfbd4c3b11e3475b022b6c1dd077613de79
  jnewbery:
    utACK ffe33dfbd4c3b11e3475b022b6c1dd077613de79
  MarcoFalke:
    review ACK ffe33dfbd4c3b11e3475b022b6c1dd077613de79 💈
  achow101:
    re-ACK ffe33dfbd4c3b11e3475b022b6c1dd077613de79
  gmaxwell:
    ACK ffe33dfbd4c3b11e3475b022b6c1dd077613de79
  benthecarman:
    ACK ffe33dfbd4c3b11e3475b022b6c1dd077613de79
  Sjors:
    ACK ffe33dfbd4c3b11e3475b022b6c1dd077613de79
  jonatack:
    Initial approach ACK ffe33dfbd4c3b11e3475b022b6c1dd077613de79 after a first pass of review, building and testing each commit, mostly looking at the changes and diffs. Will do a more high-level review iteration. A few minor comments follow to pick/choose/ignore.
  ariard:
    Code Review ACK ffe33df

Tree-SHA512: f79a7146b2450057ee92155cbbbcec12cd64334236d9239c6bd7d31b32eec145a9781c320f178da7b44ababdb8808b84d9d22a40e0851e229ba6d224e3be747c

1 files changed, 32 insertions, 17 deletions

diff --git a/src/chainparams.cpp b/src/chainparams.cpp
index 3e77883856..98bbd17c0b 100644
--- a/src/chainparams.cpp
+++ b/src/chainparams.cpp
@@ -78,16 +78,18 @@ public:
         consensus.nPowTargetSpacing = 10 * 60;
         consensus.fPowAllowMinDifficultyBlocks = false;
         consensus.fPowNoRetargeting = false;
-        consensus.nRuleChangeActivationThreshold = 1916; // 95% of 2016
+        consensus.nRuleChangeActivationThreshold = 1815; // 90% of 2016
         consensus.nMinerConfirmationWindow = 2016; // nPowTargetTimespan / nPowTargetSpacing
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].bit = 28;
-        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = 1199145601; // January 1, 2008
-        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = 1230767999; // December 31, 2008
+        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = Consensus::BIP9Deployment::NEVER_ACTIVE;
+        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
+        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].min_activation_height = 0; // No activation delay
 
         // Deployment of Taproot (BIPs 340-342)
         consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].bit = 2;
-        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nStartTime = 1199145601; // January 1, 2008
-        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nTimeout = 1230767999; // December 31, 2008
+        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nStartTime = Consensus::BIP9Deployment::NEVER_ACTIVE;
+        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
+        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].min_activation_height = 0; // No activation delay
 
         consensus.nMinimumChainWork = uint256S("0x00000000000000000000000000000000000000001533efd8d716a517fe2c5008");
         consensus.defaultAssumeValid = uint256S("0x0000000000000000000b9d2ec5a352ecba0592946514a92f14319dc2b367fc72"); // 654683
@@ -198,13 +200,15 @@ public:
         consensus.nRuleChangeActivationThreshold = 1512; // 75% for testchains
         consensus.nMinerConfirmationWindow = 2016; // nPowTargetTimespan / nPowTargetSpacing
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].bit = 28;
-        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = 1199145601; // January 1, 2008
-        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = 1230767999; // December 31, 2008
+        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = Consensus::BIP9Deployment::NEVER_ACTIVE;
+        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
+        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].min_activation_height = 0; // No activation delay
 
         // Deployment of Taproot (BIPs 340-342)
         consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].bit = 2;
-        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nStartTime = 1199145601; // January 1, 2008
-        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nTimeout = 1230767999; // December 31, 2008
+        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nStartTime = Consensus::BIP9Deployment::NEVER_ACTIVE;
+        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
+        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].min_activation_height = 0; // No activation delay
 
         consensus.nMinimumChainWork = uint256S("0x0000000000000000000000000000000000000000000001db6ec4ac88cf2272c6");
         consensus.defaultAssumeValid = uint256S("0x000000000000006433d1efec504c53ca332b64963c425395515b01977bd7b3b0"); // 1864000
@@ -328,18 +332,20 @@ public:
         consensus.nPowTargetSpacing = 10 * 60;
         consensus.fPowAllowMinDifficultyBlocks = false;
         consensus.fPowNoRetargeting = false;
-        consensus.nRuleChangeActivationThreshold = 1916; // 95% of 2016
+        consensus.nRuleChangeActivationThreshold = 1815; // 90% of 2016
         consensus.nMinerConfirmationWindow = 2016; // nPowTargetTimespan / nPowTargetSpacing
         consensus.MinBIP9WarningHeight = 0;
         consensus.powLimit = uint256S("00000377ae000000000000000000000000000000000000000000000000000000");
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].bit = 28;
-        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = 1199145601; // January 1, 2008
-        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = 1230767999; // December 31, 2008
+        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = Consensus::BIP9Deployment::NEVER_ACTIVE;
+        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
+        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].min_activation_height = 0; // No activation delay
 
         // Activation of Taproot (BIPs 340-342)
         consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].bit = 2;
         consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nStartTime = Consensus::BIP9Deployment::ALWAYS_ACTIVE;
         consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
+        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].min_activation_height = 0; // No activation delay
 
         // message start is defined as the first 4 bytes of the sha256d of the block script
         CHashWriter h(SER_DISK, 0);
@@ -398,12 +404,16 @@ public:
         consensus.fPowNoRetargeting = true;
         consensus.nRuleChangeActivationThreshold = 108; // 75% for testchains
         consensus.nMinerConfirmationWindow = 144; // Faster than normal for regtest (144 instead of 2016)
+
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].bit = 28;
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = 0;
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
+        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].min_activation_height = 0; // No activation delay
+
         consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].bit = 2;
         consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nStartTime = Consensus::BIP9Deployment::ALWAYS_ACTIVE;
         consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
+        consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].min_activation_height = 0; // No activation delay
 
         consensus.nMinimumChainWork = uint256{};
         consensus.defaultAssumeValid = uint256{};
@@ -467,10 +477,11 @@ public:
     /**
      * Allows modifying the Version Bits regtest parameters.
      */
-    void UpdateVersionBitsParameters(Consensus::DeploymentPos d, int64_t nStartTime, int64_t nTimeout)
+    void UpdateVersionBitsParameters(Consensus::DeploymentPos d, int64_t nStartTime, int64_t nTimeout, int min_activation_height)
     {
         consensus.vDeployments[d].nStartTime = nStartTime;
         consensus.vDeployments[d].nTimeout = nTimeout;
+        consensus.vDeployments[d].min_activation_height = min_activation_height;
     }
     void UpdateActivationParametersFromArgs(const ArgsManager& args);
 };
@@ -493,22 +504,26 @@ void CRegTestParams::UpdateActivationParametersFromArgs(const ArgsManager& args)
     for (const std::string& strDeployment : args.GetArgs("-vbparams")) {
         std::vector<std::string> vDeploymentParams;
         boost::split(vDeploymentParams, strDeployment, boost::is_any_of(":"));
-        if (vDeploymentParams.size() != 3) {
-            throw std::runtime_error("Version bits parameters malformed, expecting deployment:start:end");
+        if (vDeploymentParams.size() < 3 || 4 < vDeploymentParams.size()) {
+            throw std::runtime_error("Version bits parameters malformed, expecting deployment:start:end[:min_activation_height]");
         }
         int64_t nStartTime, nTimeout;
+        int min_activation_height = 0;
         if (!ParseInt64(vDeploymentParams[1], &nStartTime)) {
             throw std::runtime_error(strprintf("Invalid nStartTime (%s)", vDeploymentParams[1]));
         }
         if (!ParseInt64(vDeploymentParams[2], &nTimeout)) {
             throw std::runtime_error(strprintf("Invalid nTimeout (%s)", vDeploymentParams[2]));
         }
+        if (vDeploymentParams.size() >= 4 && !ParseInt32(vDeploymentParams[3], &min_activation_height)) {
+            throw std::runtime_error(strprintf("Invalid min_activation_height (%s)", vDeploymentParams[3]));
+        }
         bool found = false;
         for (int j=0; j < (int)Consensus::MAX_VERSION_BITS_DEPLOYMENTS; ++j) {
             if (vDeploymentParams[0] == VersionBitsDeploymentInfo[j].name) {
-                UpdateVersionBitsParameters(Consensus::DeploymentPos(j), nStartTime, nTimeout);
+                UpdateVersionBitsParameters(Consensus::DeploymentPos(j), nStartTime, nTimeout, min_activation_height);
                 found = true;
-                LogPrintf("Setting version bits activation parameters for %s to start=%ld, timeout=%ld\n", vDeploymentParams[0], nStartTime, nTimeout);
+                LogPrintf("Setting version bits activation parameters for %s to start=%ld, timeout=%ld, min_activation_height=%d\n", vDeploymentParams[0], nStartTime, nTimeout, min_activation_height);
                 break;
             }
         }