doc: ActivateBestChainStep return value

src/validation.cpp

@@ -2472,6 +2472,8 @@ void CChainState::PruneBlockIndexCandidates() {
 /**
  * Try to make some progress towards making pindexMostWork the active block.
  * pblock is either nullptr or a pointer to a CBlock corresponding to pindexMostWork.
+ *
+ * @returns true unless a system error occurred
  */
 bool CChainState::ActivateBestChainStep(CValidationState& state, const CChainParams& chainparams, CBlockIndex* pindexMostWork, const std::shared_ptr<const CBlock>& pblock, bool& fInvalidFound, ConnectTrace& connectTrace)
 {
@@ -2598,6 +2600,8 @@ static void LimitValidationInterfaceQueue() LOCKS_EXCLUDED(cs_main) {
  * ActivateBestChain is split into steps (see ActivateBestChainStep) so that
  * we avoid holding cs_main for an extended period of time; the length of this
  * call may be quite long during reindexing or a substantial reorg.
+ *
+ * @returns true unless a system error occurred
  */
 bool CChainState::ActivateBestChain(CValidationState &state, const CChainParams& chainparams, std::shared_ptr<const CBlock> pblock) {
     // Note that while we're often called here from ProcessNewBlock, this is
@@ -2646,8 +2650,10 @@ bool CChainState::ActivateBestChain(CValidationState &state, const CChainParams&
 
                 bool fInvalidFound = false;
                 std::shared_ptr<const CBlock> nullBlockPtr;
-                if (!ActivateBestChainStep(state, chainparams, pindexMostWork, pblock && pblock->GetHash() == pindexMostWork->GetBlockHash() ? pblock : nullBlockPtr, fInvalidFound, connectTrace))
+                if (!ActivateBestChainStep(state, chainparams, pindexMostWork, pblock && pblock->GetHash() == pindexMostWork->GetBlockHash() ? pblock : nullBlockPtr, fInvalidFound, connectTrace)) {
+                    // A system error occurred
                     return false;
+                }
                 blocks_connected = true;
 
                 if (fInvalidFound) {

src/validation.h

@@ -211,7 +211,7 @@ static const uint64_t MIN_DISK_SPACE_FOR_BLOCK_FILES = 550 * 1024 * 1024;
  * @param[in]   pblock  The block we want to process.
  * @param[in]   fForceProcessing Process this block even if unrequested; used for non-network block sources and whitelisted peers.
  * @param[out]  fNewBlock A boolean which is set to indicate if the block was first received via this call
- * @return True if state.IsValid()
+ * @returns     If the block was processed, independently of block validity
  */
 bool ProcessNewBlock(const CChainParams& chainparams, const std::shared_ptr<const CBlock> pblock, bool fForceProcessing, bool* fNewBlock) LOCKS_EXCLUDED(cs_main);
 
@@ -653,6 +653,8 @@ public:
      *
      * If FlushStateMode::NONE is used, then FlushStateToDisk(...) won't do anything
      * besides checking if we need to prune.
+     *
+     * @returns true unless a system error occurred
      */
     bool FlushStateToDisk(
         const CChainParams& chainparams,