Merge bitcoin/bitcoin#26883: src/node/miner cleanups, follow-ups for #26695

6a5e88e5cf06a6b410486cc36aba7afece0d9da9 miner: don't re-apply default Options value if argument is unset (stickies-v)
ea72c3d9d594b2ea9b3397e64efd08f8563cb400 refactor: avoid duplicating BlockAssembler::Options members (stickies-v)
cba749a9b7a6cd24e8887bddeb0430a1ebc783da refactor: rename local gArgs to args (stickies-v)

Pull request description:

  Two follow-ups for #26695, both refactoring and no observed (*) behaviour change:
  - Rename `gArgs` to `args` because it's not actually a global
  - Add `BlockAssembler::Options` as a (private) member to `BlockAssembler` to avoid having to assign all the options individually, essentially duplicating them

  Reduces LoC and makes the code more readable, in my opinion.

  ---

  (*) as [pointed out by ajtowns](https://github.com/bitcoin/bitcoin/pull/26883#discussion_r1068247937), this PR changes the interface of `ApplyArgsManOptions()`, making this not a pure refactoring PR. In practice, `ApplyArgsManOptions()` is never called in such a way that this leads to observed behaviour change. Regardless, I've carved out the potential behaviour change into a separate commit and would be okay with dropping it, should it turn out to be controversial.

ACKs for top commit:
  glozow:
    ACK 6a5e88e5cf
  TheCharlatan:
    Light code review ACK 6a5e88e5cf06a6b410486cc36aba7afece0d9da9

Tree-SHA512: 15c30442ff0e070b1a58dc4c9615550d619ce35b4a2596b2c0a9d790259bbf987cab708f7cbb1057a8cf8b4c3226f3ad981282d3499ac442094806492a5f68ce

2 files changed, 24 insertions, 34 deletions

diff --git a/src/node/miner.cpp b/src/node/miner.cpp
index c2b6fd1dc3..c7bc9a9a3d 100644
--- a/src/node/miner.cpp
+++ b/src/node/miner.cpp
@@ -56,34 +56,27 @@ void RegenerateCommitments(CBlock& block, ChainstateManager& chainman)
     block.hashMerkleRoot = BlockMerkleRoot(block);
 }
 
-BlockAssembler::Options::Options()
+static BlockAssembler::Options ClampOptions(BlockAssembler::Options options)
 {
-    blockMinFeeRate = CFeeRate(DEFAULT_BLOCK_MIN_TX_FEE);
-    nBlockMaxWeight = DEFAULT_BLOCK_MAX_WEIGHT;
-    test_block_validity = true;
+    // Limit weight to between 4K and DEFAULT_BLOCK_MAX_WEIGHT for sanity:
+    options.nBlockMaxWeight = std::clamp<size_t>(options.nBlockMaxWeight, 4000, DEFAULT_BLOCK_MAX_WEIGHT);
+    return options;
 }
 
 BlockAssembler::BlockAssembler(Chainstate& chainstate, const CTxMemPool* mempool, const Options& options)
-    : test_block_validity{options.test_block_validity},
-      chainparams{chainstate.m_chainman.GetParams()},
-      m_mempool(mempool),
-      m_chainstate(chainstate)
+    : chainparams{chainstate.m_chainman.GetParams()},
+      m_mempool{mempool},
+      m_chainstate{chainstate},
+      m_options{ClampOptions(options)}
 {
-    blockMinFeeRate = options.blockMinFeeRate;
-    // Limit weight to between 4K and MAX_BLOCK_WEIGHT-4K for sanity:
-    nBlockMaxWeight = std::max<size_t>(4000, std::min<size_t>(MAX_BLOCK_WEIGHT - 4000, options.nBlockMaxWeight));
 }
 
-void ApplyArgsManOptions(const ArgsManager& gArgs, BlockAssembler::Options& options)
+void ApplyArgsManOptions(const ArgsManager& args, BlockAssembler::Options& options)
 {
     // Block resource limits
-    // If -blockmaxweight is not given, limit to DEFAULT_BLOCK_MAX_WEIGHT
-    options.nBlockMaxWeight = gArgs.GetIntArg("-blockmaxweight", DEFAULT_BLOCK_MAX_WEIGHT);
-    if (gArgs.IsArgSet("-blockmintxfee")) {
-        std::optional<CAmount> parsed = ParseMoney(gArgs.GetArg("-blockmintxfee", ""));
-        options.blockMinFeeRate = CFeeRate{parsed.value_or(DEFAULT_BLOCK_MIN_TX_FEE)};
-    } else {
-        options.blockMinFeeRate = CFeeRate{DEFAULT_BLOCK_MIN_TX_FEE};
+    options.nBlockMaxWeight = args.GetIntArg("-blockmaxweight", options.nBlockMaxWeight);
+    if (const auto blockmintxfee{args.GetArg("-blockmintxfee")}) {
+        if (const auto parsed{ParseMoney(*blockmintxfee)}) options.blockMinFeeRate = CFeeRate{*parsed};
     }
 }
 static BlockAssembler::Options ConfiguredOptions()
@@ -176,7 +169,7 @@ std::unique_ptr<CBlockTemplate> BlockAssembler::CreateNewBlock(const CScript& sc
     pblocktemplate->vTxSigOpsCost[0] = WITNESS_SCALE_FACTOR * GetLegacySigOpCount(*pblock->vtx[0]);
 
     BlockValidationState state;
-    if (test_block_validity && !TestBlockValidity(state, chainparams, m_chainstate, *pblock, pindexPrev,
+    if (m_options.test_block_validity && !TestBlockValidity(state, chainparams, m_chainstate, *pblock, pindexPrev,
                                                   GetAdjustedTime, /*fCheckPOW=*/false, /*fCheckMerkleRoot=*/false)) {
         throw std::runtime_error(strprintf("%s: TestBlockValidity failed: %s", __func__, state.ToString()));
     }
@@ -205,7 +198,7 @@ void BlockAssembler::onlyUnconfirmed(CTxMemPool::setEntries& testSet)
 bool BlockAssembler::TestPackage(uint64_t packageSize, int64_t packageSigOpsCost) const
 {
     // TODO: switch to weight-based accounting for packages instead of vsize-based accounting.
-    if (nBlockWeight + WITNESS_SCALE_FACTOR * packageSize >= nBlockMaxWeight) {
+    if (nBlockWeight + WITNESS_SCALE_FACTOR * packageSize >= m_options.nBlockMaxWeight) {
         return false;
     }
     if (nBlockSigOpsCost + packageSigOpsCost >= MAX_BLOCK_SIGOPS_COST) {
@@ -377,7 +370,7 @@ void BlockAssembler::addPackageTxs(const CTxMemPool& mempool, int& nPackagesSele
             packageSigOpsCost = modit->nSigOpCostWithAncestors;
         }
 
-        if (packageFees < blockMinFeeRate.GetFee(packageSize)) {
+        if (packageFees < m_options.blockMinFeeRate.GetFee(packageSize)) {
             // Everything else we might consider has a lower fee rate
             return;
         }
@@ -394,7 +387,7 @@ void BlockAssembler::addPackageTxs(const CTxMemPool& mempool, int& nPackagesSele
             ++nConsecutiveFailed;
 
             if (nConsecutiveFailed > MAX_CONSECUTIVE_FAILURES && nBlockWeight >
-                    nBlockMaxWeight - 4000) {
+                    m_options.nBlockMaxWeight - 4000) {
                 // Give up if we're close to full and haven't succeeded in a while
                 break;
             }
diff --git a/src/node/miner.h b/src/node/miner.h
index ea9e470a64..f1ccffff55 100644
--- a/src/node/miner.h
+++ b/src/node/miner.h
@@ -6,6 +6,7 @@
 #ifndef BITCOIN_NODE_MINER_H
 #define BITCOIN_NODE_MINER_H
 
+#include <policy/policy.h>
 #include <primitives/block.h>
 #include <txmempool.h>
 
@@ -132,13 +133,6 @@ private:
     // The constructed block template
     std::unique_ptr<CBlockTemplate> pblocktemplate;
 
-    // Configuration parameters for the block size
-    unsigned int nBlockMaxWeight;
-    CFeeRate blockMinFeeRate;
-
-    // Whether to call TestBlockValidity() at the end of CreateNewBlock().
-    const bool test_block_validity;
-
     // Information on the current status of the block
     uint64_t nBlockWeight;
     uint64_t nBlockTx;
@@ -156,10 +150,11 @@ private:
 
 public:
     struct Options {
-        Options();
-        size_t nBlockMaxWeight;
-        CFeeRate blockMinFeeRate;
-        bool test_block_validity;
+        // Configuration parameters for the block size
+        size_t nBlockMaxWeight{DEFAULT_BLOCK_MAX_WEIGHT};
+        CFeeRate blockMinFeeRate{DEFAULT_BLOCK_MIN_TX_FEE};
+        // Whether to call TestBlockValidity() at the end of CreateNewBlock().
+        bool test_block_validity{true};
     };
 
     explicit BlockAssembler(Chainstate& chainstate, const CTxMemPool* mempool);
@@ -172,6 +167,8 @@ public:
     inline static std::optional<int64_t> m_last_block_weight{};
 
 private:
+    const Options m_options;
+
     // utility functions
     /** Clear the block's state and prepare for assembling a new block */
     void resetBlock();