rpc: collect transaction fees on generateblock #31775

1. 
   tiagosh commented at 0:07 am on February 1, 2025: none

   Fixes #31684

   Currently generateblock will insert the specified transactions directly into the new block without collecting fees in the coinbase transaction.

   This patch changes the code to take transaction fees into account and make it behave closer to the expected miner behavior in mainnet.

2. 
   DrahtBot commented at 0:07 am on February 1, 2025: contributor

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/31775.

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   Conflicts

   No conflicts as of last run.

3. DrahtBot added the label RPC/REST/ZMQ on Feb 1, 2025
4. tiagosh force-pushed on Feb 1, 2025
5. 
   DrahtBot commented at 0:21 am on February 1, 2025: contributor

   🚧 At least one of the CI tasks failed. Debug: https://github.com/bitcoin/bitcoin/runs/36509660013

   Try to run the tests locally, according to the documentation. However, a CI failure may still happen due to a number of reasons, for example:

   • Possibly due to a silent merge conflict (the changes in this pull request being incompatible with the current code in the target branch). If so, make sure to rebase on the latest commit of the target branch.

   • A sanitizer issue, which can only be found by compiling with the sanitizer and running the affected test.

   • An intermittent issue.

   Leave a comment here, if you need help tracking down a confusing failure.

6. DrahtBot added the label CI failed on Feb 1, 2025
7. in src/node/miner.cpp:150 in 5a02fbaf86 outdated

   143@@ -144,8 +144,16 @@ std::unique_ptr<CBlockTemplate> BlockAssembler::CreateNewBlock()
   144 
   145     int nPackagesSelected = 0;
   146     int nDescendantsUpdated = 0;
   147-    if (m_mempool) {
   148+    if (m_options.use_mempool) {
   149         addPackageTxs(nPackagesSelected, nDescendantsUpdated);
   150+    } else if (m_options.txs.size() > 0) {
   151+        EXCLUSIVE_LOCKS_REQUIRED(m_mempool->cs);
   

   ---

   ---

   

   brunoerg commented at 0:56 am on February 1, 2025:

   019:24:04.713] /ci_container_base/src/node/miner.cpp:150:9: error: 'exclusive_locks_required' attribute cannot be applied to a statement
   1[19:24:04.713]   150 |         EXCLUSIVE_LOCKS_REQUIRED(m_mempool->cs);
   2[19:24:04.713]       |         ^                                      ~
   3[19:24:04.713] /ci_container_base/src/threadsafety.h:31:54: note: expanded from macro 'EXCLUSIVE_LOCKS_REQUIRED'
   4[19:24:04.713]    31 | #define EXCLUSIVE_LOCKS_REQUIRED(...) __attribute__((exclusive_locks_required(__VA_ARGS__)))
   

8. tiagosh force-pushed on Feb 1, 2025
9. rpc: collect transaction fees on generateblock 007caf1163
10. tiagosh force-pushed on Feb 1, 2025
11. 
    maflcko commented at 11:33 am on February 4, 2025: member

    The code doesn’t pass existing tests, and doesn’t have new tests. Also, the approach won’t work anyway, because the transactions may not be in the mempool. You’d have to calculate the fees based on the prevout amounts for each transaction.
12. 
    i-am-yuvi commented at 3:58 pm on February 18, 2025: contributor

    I agree with @maflcko!

    The block reward should include both the block subsidy and the transaction fees from all transactions included in the block.

    Is there a use case for this? generateblock is a test-only RPC, so there is no need to write extra code to collect the fees. Note that the other generate* calls will collect the fees.

13. 
    maflcko commented at 4:04 pm on February 18, 2025: member

    Closing for now. For future contributions, my recommendation would be to compile the code and run the tests. Also, new tests should be included for new features.
14. maflcko closed this on Feb 18, 2025

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Contributors
tiagosh DrahtBot brunoerg maflcko i-am-yuvi

Labels
RPC/REST/ZMQ CI failed