From 73666ad05932429c860efe74eb388d212c152fc4 Mon Sep 17 00:00:00 2001
From: Matt Corallo <git@bluematt.me>
Date: Thu, 12 Jan 2017 12:15:17 -0800
Subject: [PATCH] Add comment to describe callers to ActivateBestChain

---
 src/validation.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/validation.cpp b/src/validation.cpp
index 5f0cf10cec920..a26426be576f5 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -2388,6 +2388,11 @@ static void NotifyHeaderTip() {
  * that is already loaded (to avoid loading it again from disk).
  */
 bool ActivateBestChain(CValidationState &state, const CChainParams& chainparams, std::shared_ptr<const CBlock> pblock) {
+    // Note that while we're often called here from ProcessNewBlock, this is
+    // far from a guarantee. Things in the P2P/RPC will often end up calling
+    // us in the middle of ProcessNewBlock - do not assume pblock is set
+    // sanely for performance or correctness!
+
     CBlockIndex *pindexMostWork = NULL;
     CBlockIndex *pindexNewTip = NULL;
     do {