rpc: Specify chain tip instead of chain in GetDifficulty

Author: promag

src/rpc/blockchain.cpp

@@ -58,10 +58,7 @@ static CUpdatedBlock latestblock;
  */
 double GetDifficulty(const CBlockIndex* blockindex)
 {
-    if (blockindex == nullptr)
-    {
-        return 1.0;
-    }
+    assert(blockindex);
 
     int nShift = (blockindex->nBits >> 24) & 0xff;
     double dDiff =
@@ -1247,20 +1244,21 @@ UniValue getblockchaininfo(const JSONRPCRequest& request)
 
     LOCK(cs_main);
 
+    const CBlockIndex* tip = chainActive.Tip();
     UniValue obj(UniValue::VOBJ);
     obj.pushKV("chain",                 Params().NetworkIDString());
     obj.pushKV("blocks",                (int)chainActive.Height());
     obj.pushKV("headers",               pindexBestHeader ? pindexBestHeader->nHeight : -1);
-    obj.pushKV("bestblockhash",         chainActive.Tip()->GetBlockHash().GetHex());
-    obj.pushKV("difficulty",            (double)GetDifficulty(chainActive.Tip()));
-    obj.pushKV("mediantime",            (int64_t)chainActive.Tip()->GetMedianTimePast());
-    obj.pushKV("verificationprogress",  GuessVerificationProgress(Params().TxData(), chainActive.Tip()));
+    obj.pushKV("bestblockhash",         tip->GetBlockHash().GetHex());
+    obj.pushKV("difficulty",            (double)GetDifficulty(tip));
+    obj.pushKV("mediantime",            (int64_t)tip->GetMedianTimePast());
+    obj.pushKV("verificationprogress",  GuessVerificationProgress(Params().TxData(), tip));
     obj.pushKV("initialblockdownload",  IsInitialBlockDownload());
-    obj.pushKV("chainwork",             chainActive.Tip()->nChainWork.GetHex());
+    obj.pushKV("chainwork",             tip->nChainWork.GetHex());
     obj.pushKV("size_on_disk",          CalculateCurrentUsage());
     obj.pushKV("pruned",                fPruneMode);
     if (fPruneMode) {
-        CBlockIndex* block = chainActive.Tip();
+        const CBlockIndex* block = tip;
         assert(block);
         while (block->pprev && (block->pprev->nStatus & BLOCK_HAVE_DATA)) {
             block = block->pprev;
@@ -1277,7 +1275,6 @@ UniValue getblockchaininfo(const JSONRPCRequest& request)
     }
 
     const Consensus::Params& consensusParams = Params().GetConsensus();
-    CBlockIndex* tip = chainActive.Tip();
     UniValue softforks(UniValue::VARR);
     UniValue bip9_softforks(UniValue::VOBJ);
     softforks.push_back(SoftForkDesc("bip34", 2, tip, consensusParams));

src/test/blockchain_tests.cpp

@@ -68,11 +68,4 @@ BOOST_AUTO_TEST_CASE(get_difficulty_for_very_high_target)
     TestDifficulty(0x12345678, 5913134931067755359633408.0);
 }
 
-// Verify that difficulty is 1.0 for an empty chain.
-BOOST_AUTO_TEST_CASE(get_difficulty_for_null_tip)
-{
-    double difficulty = GetDifficulty(nullptr);
-    RejectDifficultyMismatch(difficulty, 1.0);
-}
-
 BOOST_AUTO_TEST_SUITE_END()