Merge bitcoin/bitcoin#25023: Remove unused SetTip(nullptr) code

faab8dceb37a944d0763fcca390342111e6a9fcc Remove unused SetTip(nullptr) code (MacroFake)

Pull request description:

  Now that this path is no longer used after commit b51e60f91472da5216116626afc032acd5616e85, we can remove it.

  Future code should reset `CChain` by simply discarding it and constructing a fresh one.

ACKs for top commit:
  ryanofsky:
    Code review ACK faab8dceb37a944d0763fcca390342111e6a9fcc. Just moved an assert statement since last review

Tree-SHA512: 7dc273b11133d85d32ca2a69c0c7c07b39cdd338141ef5b51496e7de334a809864d5459eb95535497866c8b1e468aae84ed8f91b543041e6ee20130d5622874e

5 files changed, 15 insertions, 16 deletions

diff --git a/src/chain.cpp b/src/chain.cpp
index 0f898bafd5..446bb216c2 100644
--- a/src/chain.cpp
+++ b/src/chain.cpp
@@ -18,11 +18,9 @@ std::string CBlockIndex::ToString() const
                      pprev, nHeight, hashMerkleRoot.ToString(), GetBlockHash().ToString());
 }
 
-void CChain::SetTip(CBlockIndex *pindex) {
-    if (pindex == nullptr) {
-        vChain.clear();
-        return;
-    }
+void CChain::SetTip(CBlockIndex& block)
+{
+    CBlockIndex* pindex = █
     vChain.resize(pindex->nHeight + 1);
     while (pindex && vChain[pindex->nHeight] != pindex) {
         vChain[pindex->nHeight] = pindex;
diff --git a/src/chain.h b/src/chain.h
index 627a3dfab2..1c5cd3f1f6 100644
--- a/src/chain.h
+++ b/src/chain.h
@@ -465,7 +465,7 @@ public:
     }
 
     /** Set/initialize a chain with a given tip. */
-    void SetTip(CBlockIndex* pindex);
+    void SetTip(CBlockIndex& block);
 
     /** Return a CBlockLocator that refers to a block in this chain (by default the tip). */
     CBlockLocator GetLocator(const CBlockIndex* pindex = nullptr) const;
diff --git a/src/test/miner_tests.cpp b/src/test/miner_tests.cpp
index 20d670c1e1..df04bfcc2f 100644
--- a/src/test/miner_tests.cpp
+++ b/src/test/miner_tests.cpp
@@ -325,7 +325,7 @@ void MinerTestingSetup::TestBasicMining(const CChainParams& chainparams, const C
         next->pprev = prev;
         next->nHeight = prev->nHeight + 1;
         next->BuildSkip();
-        m_node.chainman->ActiveChain().SetTip(next);
+        m_node.chainman->ActiveChain().SetTip(*next);
     }
     BOOST_CHECK(pblocktemplate = AssemblerForTest(chainparams).CreateNewBlock(scriptPubKey));
     // Extend to a 210000-long block chain.
@@ -337,7 +337,7 @@ void MinerTestingSetup::TestBasicMining(const CChainParams& chainparams, const C
         next->pprev = prev;
         next->nHeight = prev->nHeight + 1;
         next->BuildSkip();
-        m_node.chainman->ActiveChain().SetTip(next);
+        m_node.chainman->ActiveChain().SetTip(*next);
     }
     BOOST_CHECK(pblocktemplate = AssemblerForTest(chainparams).CreateNewBlock(scriptPubKey));
 
@@ -362,7 +362,7 @@ void MinerTestingSetup::TestBasicMining(const CChainParams& chainparams, const C
     // Delete the dummy blocks again.
     while (m_node.chainman->ActiveChain().Tip()->nHeight > nHeight) {
         CBlockIndex* del = m_node.chainman->ActiveChain().Tip();
-        m_node.chainman->ActiveChain().SetTip(del->pprev);
+        m_node.chainman->ActiveChain().SetTip(*Assert(del->pprev));
         m_node.chainman->ActiveChainstate().CoinsTip().SetBestBlock(del->pprev->GetBlockHash());
         delete del->phashBlock;
         delete del;
diff --git a/src/test/skiplist_tests.cpp b/src/test/skiplist_tests.cpp
index 6dadf09176..3d3fd5d93d 100644
--- a/src/test/skiplist_tests.cpp
+++ b/src/test/skiplist_tests.cpp
@@ -72,7 +72,7 @@ BOOST_AUTO_TEST_CASE(getlocator_test)
 
     // Build a CChain for the main branch.
     CChain chain;
-    chain.SetTip(&vBlocksMain.back());
+    chain.SetTip(vBlocksMain.back());
 
     // Test 100 random starting points for locators.
     for (int n=0; n<100; n++) {
@@ -128,7 +128,7 @@ BOOST_AUTO_TEST_CASE(findearliestatleast_test)
 
     // Build a CChain for the main branch.
     CChain chain;
-    chain.SetTip(&vBlocksMain.back());
+    chain.SetTip(vBlocksMain.back());
 
     // Verify that FindEarliestAtLeast is correct.
     for (unsigned int i=0; i<10000; ++i) {
@@ -155,7 +155,7 @@ BOOST_AUTO_TEST_CASE(findearliestatleast_edge_test)
     }
 
     CChain chain;
-    chain.SetTip(&blocks.back());
+    chain.SetTip(blocks.back());
 
     BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(50, 0)->nHeight, 0);
     BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(100, 0)->nHeight, 0);
diff --git a/src/validation.cpp b/src/validation.cpp
index c924bb3c34..d30333f710 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -2583,6 +2583,7 @@ bool CChainState::DisconnectTip(BlockValidationState& state, DisconnectedBlockTr
 
     CBlockIndex *pindexDelete = m_chain.Tip();
     assert(pindexDelete);
+    assert(pindexDelete->pprev);
     // Read block from disk.
     std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
     CBlock& block = *pblock;
@@ -2630,7 +2631,7 @@ bool CChainState::DisconnectTip(BlockValidationState& state, DisconnectedBlockTr
         }
     }
 
-    m_chain.SetTip(pindexDelete->pprev);
+    m_chain.SetTip(*pindexDelete->pprev);
 
     UpdateTip(pindexDelete->pprev);
     // Let wallets know transactions went from 1-confirmed to
@@ -2744,7 +2745,7 @@ bool CChainState::ConnectTip(BlockValidationState& state, CBlockIndex* pindexNew
         disconnectpool.removeForBlock(blockConnecting.vtx);
     }
     // Update m_chain & related variables.
-    m_chain.SetTip(pindexNew);
+    m_chain.SetTip(*pindexNew);
     UpdateTip(pindexNew);
 
     int64_t nTime6 = GetTimeMicros(); nTimePostConnect += nTime6 - nTime5; nTimeTotal += nTime6 - nTime1;
@@ -3892,7 +3893,7 @@ bool CChainState::LoadChainTip()
     if (!pindex) {
         return false;
     }
-    m_chain.SetTip(pindex);
+    m_chain.SetTip(*pindex);
     PruneBlockIndexCandidates();
 
     tip = m_chain.Tip();
@@ -4969,7 +4970,7 @@ bool ChainstateManager::PopulateAndValidateSnapshot(
         return false;
     }
 
-    snapshot_chainstate.m_chain.SetTip(snapshot_start_block);
+    snapshot_chainstate.m_chain.SetTip(*snapshot_start_block);
 
     // The remainder of this function requires modifying data protected by cs_main.
     LOCK(::cs_main);