test: mining: add coverage for GBT’s “coinbasevalue” result field #34958

1. 
   theStack commented at 5:13 pm on March 30, 2026: contributor

   This PR adds missing coverage for the “coinbasevalue” result field of the getblocktemplate RPC call. Specifically, the introduced test checks that the value is set to claim the full block reward (subsidy plus fees). Can be verified with the following patch, which succeeds on master and fails on the PR branch:

    0diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
    1index a935810d91..ba9ac9dadb 100644
    2--- a/src/rpc/mining.cpp
    3+++ b/src/rpc/mining.cpp
    4@@ -998,7 +998,7 @@ static RPCHelpMan getblocktemplate()
    5     result.pushKV("previousblockhash", block.hashPrevBlock.GetHex());
    6     result.pushKV("transactions", std::move(transactions));
    7     result.pushKV("coinbaseaux", std::move(aux));
    8-    result.pushKV("coinbasevalue", block.vtx[0]->vout[0].nValue);
    9+    result.pushKV("coinbasevalue", block.vtx[0]->vout[0].nValue - 1);
   10     result.pushKV("longpollid", tip.GetHex() + ToString(nTransactionsUpdatedLast));
   11     result.pushKV("target", hashTarget.GetHex());
   12     result.pushKV("mintime", GetMinimumTime(pindexPrev, consensusParams.DifficultyAdjustmentInterval()));
   

   I’m not sure how relevant this field is nowadays in real-world mining scenarios (we use it for the signet miner at least), but it seems useful to have a test for it anyways. Stumbled upon this while looking at https://github.com/bitcoin-inquisition/bitcoin/pull/111.

2. test: mining: add coverage for GBT's "coinbasevalue" result field

   Add missing test coverage for the `getblocktemplate` RPC call
   "coinbasevalue" field, specifically that it is set to claim the
   full block reward.

   12c3c3f81d
3. DrahtBot added the label Tests on Mar 30, 2026
4. 
   DrahtBot commented at 5:14 pm on March 30, 2026: contributor

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5. bitcoin deleted a comment on Mar 30, 2026
6. 
   maflcko commented at 7:05 am on March 31, 2026: member

   lgtm ACK 12c3c3f81d52b852cf51b549a5de4d55b0ed624b
7. 
   Sjors commented at 7:13 am on March 31, 2026: member

   ACK 12c3c3f81d52b852cf51b549a5de4d55b0ed624b

   You could also make this cover the IPC CoinbaseTx struct:

    0--- a/src/rpc/mining.cpp
    1+++ b/src/rpc/mining.cpp
    2@@ -999,5 +999,6 @@ static RPCHelpMan getblocktemplate()
    3     result.pushKV("transactions", std::move(transactions));
    4     result.pushKV("coinbaseaux", std::move(aux));
    5-    result.pushKV("coinbasevalue", block.vtx[0]->vout[0].nValue);
    6+    const auto coinbase{block_template->getCoinbaseTx()};
    7+    result.pushKV("coinbasevalue", coinbase.block_reward_remaining);
    8     result.pushKV("longpollid", tip.GetHex() + ToString(nTransactionsUpdatedLast));
    9     result.pushKV("target", hashTarget.GetHex());
   10@@ -1026,5 +1027,5 @@ static RPCHelpMan getblocktemplate()
   11     }
   12
   13-    if (auto coinbase{block_template->getCoinbaseTx()}; coinbase.required_outputs.size() > 0) {
   14+    if (coinbase.required_outputs.size() > 0) {
   15         CHECK_NONFATAL(coinbase.required_outputs.size() == 1); // Only one output is currently expected
   16         result.pushKV("default_witness_commitment", HexStr(coinbase.required_outputs[0].scriptPubKey));
   

Contributors
theStack DrahtBot maflcko Sjors

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Tests