mining: move BlockAssembler statics into BlockTemplateManager #36357

pull w0xlt wants to merge 3 commits into bitcoin:master from w0xlt:block-template-manager-last-block-stats changing 5 files +201 −44

w0xlt commented at 9:09 AM on September 27, 2026: contributor
Based on #36356. Together with it, this completes the "Remove remaining global states" TODO in #33758.

getmininginfo reports currentblockweight and currentblocktx from two process-wide statics, BlockAssembler::m_last_block_weight and m_last_block_num_txs, which every BlockAssembler::CreateNewBlock() call overwrites.

Like the getblocktemplate statics, they are shared by every node context in the process and nothing checks their locking. They also record templates that were not built for mining: the mempool fee estimator builds its own templates with BlockAssembler, so getmininginfo can report the fee estimator's template instead of the last mining template.

This PR:
- makes the two fields per-BlockAssembler instance, still set at the same point in CreateNewBlock();
- has BlockTemplateManager::CreateNewTemplate() record them in a member guarded by cs_main, which getmininginfo reads. CreateNewTemplate() now holds cs_main across the build, as CreateNewBlock() already did internally, so concurrent builds cannot record their stats out of order;
- adds a unit test showing that manager builds are recorded, that the latest one wins, and that a direct BlockAssembler build is ignored.
In short: the last global mining state moves out of BlockAssembler, and getmininginfo reports the last template built for mining rather than whatever the node assembled last.

node: cache a getblocktemplate template in BlockTemplateManager

Add a CachedBlockTemplate member to BlockTemplateManager, guarded by
cs_main, along with GetCachedTransactionsUpdated() and
RefreshCachedTemplate().

RefreshCachedTemplate() follows the rules of the function-local statics
in the getblocktemplate RPC, which the next commit replaces: the template
is rebuilt when the tip changes, or when the mempool changed and the
cached template is more than 5 seconds old. A failed rebuild leaves the
cached template unset so that the next call tries again. The deprecated
GetTime() is replaced with the equivalent Now<NodeSeconds>().

Unlike the RPC, RefreshCachedTemplate() does not take the tip from the
caller or cache its CBlockIndex. It reads the active chain tip itself
and compares it with the template's hashPrevBlock, so the cache cannot
pair a template with a tip it does not build on.

ccb8e84039

rpc: use the BlockTemplateManager cache in getblocktemplate

Replace the function-local statics in getblocktemplate with the template
cached by BlockTemplateManager. The state now lives as long as the node
context instead of the process, and its synchronization is checked
through GUARDED_BY(::cs_main).

The static CBlockIndex pointer is not carried over: pindexPrev is looked
up from the template's hashPrevBlock, so it can no longer outlive the
ChainstateManager that owns it. The longpollid is built from
hashPrevBlock as well, so it always names the block the template builds
on, and the tip no longer needs to be re-read after longpolling.

5cbfbc6b92

node: move last block stats into BlockTemplateManager

BlockAssembler::m_last_block_num_txs and m_last_block_weight were
process-wide statics, written by every BlockAssembler::CreateNewBlock()
call and read by getmininginfo as currentblocktx and currentblockweight.

Make them per-instance, and have
BlockTemplateManager::CreateNewTemplate() copy them into a member
guarded by cs_main, which getmininginfo reads.
CreateNewTemplate() now holds cs_main across the build, as
CreateNewBlock() already did internally, so concurrent builds cannot
record their stats out of order.

Behavior change: only templates built through BlockTemplateManager
(getblocktemplate, the generate RPCs and the mining interface) update
these fields. Templates that the mempool fee estimator builds with
BlockAssembler directly no longer do, and neither does a build that
throws after assembling the block (e.g. a TestBlockValidity() failure).

Update the getmininginfo help text to match.

e47e7acca3

DrahtBot added the label Mining on Sep 27, 2026
DrahtBot commented at 9:10 AM on September 27, 2026: 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/36357.



Reviews

See the guideline and AI policy for information on the review process. A summary of reviews will appear here.
w0xlt marked this as a draft on Sep 27, 2026

Contributors

w0xlt

DrahtBot

Labels

Mining

Linked (view graph)

#33758 BlockTemplate Manager Tracking issue #36356 mining: move getblocktemplate cache into BlockTemplateManager

mining: move BlockAssembler statics into BlockTemplateManager #36357

Code Coverage & Benchmarks

Reviews