[refactor] Replace global int nScriptCheckThreads with bool

The global nScriptCheckThreads int is confusing and is only needed for
its int-ness in AppInitMain. Move all `-par` parsing logic there and
replace the int nScriptCheckThreads with a bool
g_parallel_script_checks.

Also tidy up logic and improve comments.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index ca6d2176b3..df01b3abcf 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -107,7 +107,7 @@ CBlockIndex *pindexBestHeader = nullptr;
 Mutex g_best_block_mutex;
 std::condition_variable g_best_block_cv;
 uint256 g_best_block;
-int nScriptCheckThreads = 0;
+bool g_parallel_script_checks{false};
 std::atomic_bool fImporting(false);
 std::atomic_bool fReindex(false);
 bool fHavePruned = false;
@@ -2069,7 +2069,7 @@ bool CChainState::ConnectBlock(const CBlock& block, BlockValidationState& state,
 
     CBlockUndo blockundo;
 
-    CCheckQueueControl<CScriptCheck> control(fScriptChecks && nScriptCheckThreads ? &scriptcheckqueue : nullptr);
+    CCheckQueueControl<CScriptCheck> control(fScriptChecks && g_parallel_script_checks ? &scriptcheckqueue : nullptr);
 
     std::vector<int> prevheights;
     CAmount nFees = 0;
@@ -2130,7 +2130,7 @@ bool CChainState::ConnectBlock(const CBlock& block, BlockValidationState& state,
             std::vector<CScriptCheck> vChecks;
             bool fCacheResults = fJustCheck; /* Don't cache results if we're actually connecting blocks (still consult the cache, though) */
             TxValidationState tx_state;
-            if (fScriptChecks && !CheckInputs(tx, tx_state, view, flags, fCacheResults, fCacheResults, txdata[i], nScriptCheckThreads ? &vChecks : nullptr)) {
+            if (fScriptChecks && !CheckInputs(tx, tx_state, view, flags, fCacheResults, fCacheResults, txdata[i], g_parallel_script_checks ? &vChecks : nullptr)) {
                 // Any transaction validation failure in ConnectBlock is a block consensus failure
                 state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                               tx_state.GetRejectReason(), tx_state.GetDebugMessage());