From 8d004ee94707c052f855b221aa14b53df3745203 Mon Sep 17 00:00:00 2001
From: Greg Fitzgerald <greg@solana.com>
Date: Thu, 28 Feb 2019 09:44:17 -0700
Subject: [PATCH] Clarify is_full

---
 src/blocktree.rs | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/blocktree.rs b/src/blocktree.rs
index 52888578dd..920e926e42 100644
--- a/src/blocktree.rs
+++ b/src/blocktree.rs
@@ -142,7 +142,15 @@ pub struct SlotMeta {
 
 impl SlotMeta {
     pub fn is_full(&self) -> bool {
-        self.consumed > self.last_index
+        // last_index is std::u64::MAX when it has no information about how
+        // many blobs will fill this slot.
+        // Note: A full slot with zero blobs is not possible.
+        if self.last_index == std::u64::MAX {
+            return false;
+        }
+        assert!(self.consumed <= self.last_index + 1);
+
+        self.consumed == self.last_index + 1
     }
 
     fn new(slot_height: u64, parent_slot: u64) -> Self {