rpc: add target and bits to getchainstates

Author: Sjors

src/rpc/blockchain.cpp

@@ -3308,6 +3308,8 @@ static RPCHelpMan loadtxoutset()
 const std::vector<RPCResult> RPCHelpForChainstate{
     {RPCResult::Type::NUM, "blocks", "number of blocks in this chainstate"},
     {RPCResult::Type::STR_HEX, "bestblockhash", "blockhash of the tip"},
+    {RPCResult::Type::STR_HEX, "bits", "nBits: compact representation of the block difficulty target"},
+    {RPCResult::Type::STR_HEX, "target", "The difficulty target"},
     {RPCResult::Type::NUM, "difficulty", "difficulty of the tip"},
     {RPCResult::Type::NUM, "verificationprogress", "progress towards the network tip"},
     {RPCResult::Type::STR_HEX, "snapshot_blockhash", /*optional=*/true, "the base block of the snapshot this chainstate is based on, if any"},
@@ -3350,6 +3352,8 @@ return RPCHelpMan{
 
         data.pushKV("blocks",                (int)chain.Height());
         data.pushKV("bestblockhash",         tip->GetBlockHash().GetHex());
+        data.pushKV("bits", strprintf("%08x", tip->nBits));
+        data.pushKV("target", GetTarget(*tip, chainman.GetConsensus().powLimit).GetHex());
         data.pushKV("difficulty", GetDifficulty(*tip));
         data.pushKV("verificationprogress", chainman.GuessVerificationProgress(tip));
         data.pushKV("coins_db_cache_bytes",  cs.m_coinsdb_cache_size_bytes);

test/functional/feature_assumeutxo.py

@@ -38,6 +38,12 @@
     getnewdestination,
     MiniWallet,
 )
+from test_framework.blocktools import (
+    REGTEST_N_BITS,
+    REGTEST_TARGET,
+    nbits_str,
+    target_str,
+)
 
 START_HEIGHT = 199
 SNAPSHOT_BASE_HEIGHT = 299
@@ -229,6 +235,12 @@ def test_snapshot_in_a_divergent_chain(self, dump_output_path):
         assert_equal(normal['blocks'], START_HEIGHT + 99)
         assert_equal(snapshot['blocks'], SNAPSHOT_BASE_HEIGHT)
 
+        # Both states should have the same nBits and target
+        assert_equal(normal['bits'], nbits_str(REGTEST_N_BITS))
+        assert_equal(normal['bits'], snapshot['bits'])
+        assert_equal(normal['target'], target_str(REGTEST_TARGET))
+        assert_equal(normal['target'], snapshot['target'])
+
         # Now lets sync the nodes and wait for the background validation to finish
         self.connect_nodes(0, 3)
         self.sync_blocks(nodes=(n0, n3))