Merge #16060: Bury bip9 deployments

e78aaf41f43d0e2ad78fa6d8dad61032c8ef73d0 [docs] Add release notes for burying bip 9 soft fork deployments (John Newbery)
8319e738f9f118025b332e4fa804d4c31e4113f4 [tests] Add coverage for the content of getblockchaininfo.softforks (James O'Beirne)
0328dcdcfcb56dc8918697716d7686be048ad0b3 [Consensus] Bury segwit deployment (John Newbery)
1c93b9b31c2ab7358f9d55f52dd46340397c906d [Consensus] Bury CSV deployment height (John Newbery)
3862e473f0cb71a762c0306b171b591341d58142 [rpc] Tidy up reporting of buried and ongoing softforks (John Newbery)

Pull request description:

  This hardcodes CSV and segwit activation heights, similar to the BIP 90 buried deployments for BIPs 34, 65 and 66.

  CSV and segwit have been active for over 18 months. Hardcoding the activation height is a code simplification, makes it easier to understand segwit activation status, and reduces technical debt.

  This was originally attempted by jl2012 in #11398 and again by me in #12360.

ACKs for top commit:
  ajtowns:
    ACK e78aaf41f43d0e2ad78fa6d8dad61032c8ef73d0 ; checked diff to previous acked commit, checked tests still work
  ariard:
    ACK e78aaf4, check diff, run the tests again and successfully activated csv/segwit heights on mainnet as expected.
  MarcoFalke:
    ACK e78aaf41f43d0e2ad78fa6d8dad61032c8ef73d0 (still didn't check if the mainnet block heights are correct, but the code looks good now)

Tree-SHA512: 7e951829106e21a81725f7d3e236eddbb59349189740907bb47e33f5dbf95c43753ac1231f47ae7bee85c8c81b2146afcdfdc11deb1503947f23093a9c399912

2 files changed, 68 insertions, 80 deletions

diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index e3d5394a2c..bfb6ab6a21 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -1188,54 +1188,49 @@ static UniValue verifychain(const JSONRPCRequest& request)
         Params(), &::ChainstateActive().CoinsTip(), nCheckLevel, nCheckDepth);
 }
 
-/** Implementation of IsSuperMajority with better feedback */
-static UniValue SoftForkMajorityDesc(int version, const CBlockIndex* pindex, const Consensus::Params& consensusParams)
+static void BuriedForkDescPushBack(UniValue& softforks, const std::string &name, int height) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
 {
-    UniValue rv(UniValue::VOBJ);
-    bool activated = false;
-    switch(version)
-    {
-        case 2:
-            activated = pindex->nHeight >= consensusParams.BIP34Height;
-            break;
-        case 3:
-            activated = pindex->nHeight >= consensusParams.BIP66Height;
-            break;
-        case 4:
-            activated = pindex->nHeight >= consensusParams.BIP65Height;
-            break;
-    }
-    rv.pushKV("status", activated);
-    return rv;
-}
+    // For buried deployments.
+    // A buried deployment is one where the height of the activation has been hardcoded into
+    // the client implementation long after the consensus change has activated. See BIP 90.
+    // Buried deployments with activation height value of
+    // std::numeric_limits<int>::max() are disabled and thus hidden.
+    if (height == std::numeric_limits<int>::max()) return;
 
-static UniValue SoftForkDesc(const std::string &name, int version, const CBlockIndex* pindex, const Consensus::Params& consensusParams)
-{
     UniValue rv(UniValue::VOBJ);
-    rv.pushKV("id", name);
-    rv.pushKV("version", version);
-    rv.pushKV("reject", SoftForkMajorityDesc(version, pindex, consensusParams));
-    return rv;
+    rv.pushKV("type", "buried");
+    // getblockchaininfo reports the softfork as active from when the chain height is
+    // one below the activation height
+    rv.pushKV("active", ::ChainActive().Tip()->nHeight + 1 >= height);
+    rv.pushKV("height", height);
+    softforks.pushKV(name, rv);
 }
 
-static UniValue BIP9SoftForkDesc(const Consensus::Params& consensusParams, Consensus::DeploymentPos id)
+static void BIP9SoftForkDescPushBack(UniValue& softforks, const std::string &name, const Consensus::Params& consensusParams, Consensus::DeploymentPos id) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
 {
-    UniValue rv(UniValue::VOBJ);
+    // For BIP9 deployments.
+    // Deployments (e.g. testdummy) with timeout value before Jan 1, 2009 are hidden.
+    // A timeout value of 0 guarantees a softfork will never be activated.
+    // This is used when merging logic to implement a proposed softfork without a specified deployment schedule.
+    if (consensusParams.vDeployments[id].nTimeout <= 1230768000) return;
+
+    UniValue bip9(UniValue::VOBJ);
     const ThresholdState thresholdState = VersionBitsTipState(consensusParams, id);
     switch (thresholdState) {
-    case ThresholdState::DEFINED: rv.pushKV("status", "defined"); break;
-    case ThresholdState::STARTED: rv.pushKV("status", "started"); break;
-    case ThresholdState::LOCKED_IN: rv.pushKV("status", "locked_in"); break;
-    case ThresholdState::ACTIVE: rv.pushKV("status", "active"); break;
-    case ThresholdState::FAILED: rv.pushKV("status", "failed"); break;
+    case ThresholdState::DEFINED: bip9.pushKV("status", "defined"); break;
+    case ThresholdState::STARTED: bip9.pushKV("status", "started"); break;
+    case ThresholdState::LOCKED_IN: bip9.pushKV("status", "locked_in"); break;
+    case ThresholdState::ACTIVE: bip9.pushKV("status", "active"); break;
+    case ThresholdState::FAILED: bip9.pushKV("status", "failed"); break;
     }
     if (ThresholdState::STARTED == thresholdState)
     {
-        rv.pushKV("bit", consensusParams.vDeployments[id].bit);
+        bip9.pushKV("bit", consensusParams.vDeployments[id].bit);
     }
-    rv.pushKV("startTime", consensusParams.vDeployments[id].nStartTime);
-    rv.pushKV("timeout", consensusParams.vDeployments[id].nTimeout);
-    rv.pushKV("since", VersionBitsTipStateSinceHeight(consensusParams, id));
+    bip9.pushKV("startTime", consensusParams.vDeployments[id].nStartTime);
+    bip9.pushKV("timeout", consensusParams.vDeployments[id].nTimeout);
+    int64_t since_height = VersionBitsTipStateSinceHeight(consensusParams, id);
+    bip9.pushKV("since", since_height);
     if (ThresholdState::STARTED == thresholdState)
     {
         UniValue statsUV(UniValue::VOBJ);
@@ -1245,18 +1240,18 @@ static UniValue BIP9SoftForkDesc(const Consensus::Params& consensusParams, Conse
         statsUV.pushKV("elapsed", statsStruct.elapsed);
         statsUV.pushKV("count", statsStruct.count);
         statsUV.pushKV("possible", statsStruct.possible);
-        rv.pushKV("statistics", statsUV);
+        bip9.pushKV("statistics", statsUV);
     }
-    return rv;
-}
 
-static void BIP9SoftForkDescPushBack(UniValue& bip9_softforks, const Consensus::Params& consensusParams, Consensus::DeploymentPos id)
-{
-    // Deployments with timeout value of 0 are hidden.
-    // A timeout value of 0 guarantees a softfork will never be activated.
-    // This is used when softfork codes are merged without specifying the deployment schedule.
-    if (consensusParams.vDeployments[id].nTimeout > 0)
-        bip9_softforks.pushKV(VersionBitsDeploymentInfo[id].name, BIP9SoftForkDesc(consensusParams, id));
+    UniValue rv(UniValue::VOBJ);
+    rv.pushKV("type", "bip9");
+    rv.pushKV("bip9", bip9);
+    if (ThresholdState::ACTIVE == thresholdState) {
+        rv.pushKV("height", since_height);
+    }
+    rv.pushKV("active", ThresholdState::ACTIVE == thresholdState);
+
+    softforks.pushKV(name, rv);
 }
 
 UniValue getblockchaininfo(const JSONRPCRequest& request)
@@ -1280,29 +1275,25 @@ UniValue getblockchaininfo(const JSONRPCRequest& request)
             "  \"pruneheight\": xxxxxx,        (numeric) lowest-height complete block stored (only present if pruning is enabled)\n"
             "  \"automatic_pruning\": xx,      (boolean) whether automatic pruning is enabled (only present if pruning is enabled)\n"
             "  \"prune_target_size\": xxxxxx,  (numeric) the target size used by pruning (only present if automatic pruning is enabled)\n"
-            "  \"softforks\": [                (array) status of softforks in progress\n"
-            "     {\n"
-            "        \"id\": \"xxxx\",           (string) name of softfork\n"
-            "        \"version\": xx,          (numeric) block version\n"
-            "        \"reject\": {             (object) progress toward rejecting pre-softfork blocks\n"
-            "           \"status\": xx,        (boolean) true if threshold reached\n"
-            "        },\n"
-            "     }, ...\n"
-            "  ],\n"
-            "  \"bip9_softforks\": {           (object) status of BIP9 softforks in progress\n"
+            "  \"softforks\": {                (object) status of softforks\n"
             "     \"xxxx\" : {                 (string) name of the softfork\n"
-            "        \"status\": \"xxxx\",       (string) one of \"defined\", \"started\", \"locked_in\", \"active\", \"failed\"\n"
-            "        \"bit\": xx,              (numeric) the bit (0-28) in the block version field used to signal this softfork (only for \"started\" status)\n"
-            "        \"startTime\": xx,        (numeric) the minimum median time past of a block at which the bit gains its meaning\n"
-            "        \"timeout\": xx,          (numeric) the median time past of a block at which the deployment is considered failed if not yet locked in\n"
-            "        \"since\": xx,            (numeric) height of the first block to which the status applies\n"
-            "        \"statistics\": {         (object) numeric statistics about BIP9 signalling for a softfork (only for \"started\" status)\n"
-            "           \"period\": xx,        (numeric) the length in blocks of the BIP9 signalling period \n"
-            "           \"threshold\": xx,     (numeric) the number of blocks with the version bit set required to activate the feature \n"
-            "           \"elapsed\": xx,       (numeric) the number of blocks elapsed since the beginning of the current period \n"
-            "           \"count\": xx,         (numeric) the number of blocks with the version bit set in the current period \n"
-            "           \"possible\": xx       (boolean) returns false if there are not enough blocks left in this period to pass activation threshold \n"
-            "        }\n"
+            "        \"type\": \"xxxx\",         (string) one of \"buried\", \"bip9\"\n"
+            "        \"bip9\": {               (object) status of bip9 softforks (only for \"bip9\" type)\n"
+            "           \"status\": \"xxxx\",    (string) one of \"defined\", \"started\", \"locked_in\", \"active\", \"failed\"\n"
+            "           \"bit\": xx,           (numeric) the bit (0-28) in the block version field used to signal this softfork (only for \"started\" status)\n"
+            "           \"startTime\": xx,     (numeric) the minimum median time past of a block at which the bit gains its meaning\n"
+            "           \"timeout\": xx,       (numeric) the median time past of a block at which the deployment is considered failed if not yet locked in\n"
+            "           \"since\": xx,         (numeric) height of the first block to which the status applies\n"
+            "           \"statistics\": {      (object) numeric statistics about BIP9 signalling for a softfork\n"
+            "              \"period\": xx,     (numeric) the length in blocks of the BIP9 signalling period \n"
+            "              \"threshold\": xx,  (numeric) the number of blocks with the version bit set required to activate the feature \n"
+            "              \"elapsed\": xx,    (numeric) the number of blocks elapsed since the beginning of the current period \n"
+            "              \"count\": xx,      (numeric) the number of blocks with the version bit set in the current period \n"
+            "              \"possible\": xx    (boolean) returns false if there are not enough blocks left in this period to pass activation threshold \n"
+            "           }\n"
+            "        },\n"
+            "        \"height\": \"xxxxxx\",     (numeric) height of the first block which the rules are or will be enforced (only for \"buried\" type, or \"bip9\" type with \"active\" status)\n"
+            "        \"active\": xx,           (boolean) true if the rules are enforced for the mempool and the next block\n"
             "     }\n"
             "  }\n"
             "  \"warnings\" : \"...\",           (string) any network and blockchain warnings.\n"
@@ -1347,16 +1338,14 @@ UniValue getblockchaininfo(const JSONRPCRequest& request)
     }
 
     const Consensus::Params& consensusParams = Params().GetConsensus();
-    UniValue softforks(UniValue::VARR);
-    UniValue bip9_softforks(UniValue::VOBJ);
-    softforks.push_back(SoftForkDesc("bip34", 2, tip, consensusParams));
-    softforks.push_back(SoftForkDesc("bip66", 3, tip, consensusParams));
-    softforks.push_back(SoftForkDesc("bip65", 4, tip, consensusParams));
-    for (int pos = Consensus::DEPLOYMENT_CSV; pos != Consensus::MAX_VERSION_BITS_DEPLOYMENTS; ++pos) {
-        BIP9SoftForkDescPushBack(bip9_softforks, consensusParams, static_cast<Consensus::DeploymentPos>(pos));
-    }
+    UniValue softforks(UniValue::VOBJ);
+    BuriedForkDescPushBack(softforks, "bip34", consensusParams.BIP34Height);
+    BuriedForkDescPushBack(softforks, "bip66", consensusParams.BIP66Height);
+    BuriedForkDescPushBack(softforks, "bip65", consensusParams.BIP65Height);
+    BuriedForkDescPushBack(softforks, "csv", consensusParams.CSVHeight);
+    BuriedForkDescPushBack(softforks, "segwit", consensusParams.SegwitHeight);
+    BIP9SoftForkDescPushBack(softforks, "testdummy", consensusParams, Consensus::DEPLOYMENT_TESTDUMMY);
     obj.pushKV("softforks",             softforks);
-    obj.pushKV("bip9_softforks", bip9_softforks);
 
     obj.pushKV("warnings", GetWarnings("statusbar"));
     return obj;
diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
index 92a0e33769..07c2958635 100644
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -482,9 +482,8 @@ static UniValue getblocktemplate(const JSONRPCRequest& request)
         // TODO: Maybe recheck connections/IBD and (if something wrong) send an expires-immediately template to stop miners?
     }
 
-    const struct VBDeploymentInfo& segwit_info = VersionBitsDeploymentInfo[Consensus::DEPLOYMENT_SEGWIT];
     // GBT must be called with 'segwit' set in the rules
-    if (setClientRules.count(segwit_info.name) != 1) {
+    if (setClientRules.count("segwit") != 1) {
         throw JSONRPCError(RPC_INVALID_PARAMETER, "getblocktemplate must be called with the segwit rule set (call with {\"rules\": [\"segwit\"]})");
     }
 
@@ -521,7 +520,7 @@ static UniValue getblocktemplate(const JSONRPCRequest& request)
     pblock->nNonce = 0;
 
     // NOTE: If at some point we support pre-segwit miners post-segwit-activation, this needs to take segwit support into consideration
-    const bool fPreSegWit = (ThresholdState::ACTIVE != VersionBitsState(pindexPrev, consensusParams, Consensus::DEPLOYMENT_SEGWIT, versionbitscache));
+    const bool fPreSegWit = (pindexPrev->nHeight + 1 < consensusParams.SegwitHeight);
 
     UniValue aCaps(UniValue::VARR); aCaps.push_back("proposal");