From 3b85cbc504f14339e343d892638961f9d82dfe00 Mon Sep 17 00:00:00 2001
From: behzad nouri <behzadnouri@gmail.com>
Date: Tue, 16 Mar 2021 10:09:16 +0000
Subject: [PATCH] renames is_last_in_fec_set back to is_last_data (#15848)

https://github.com/solana-labs/solana/pull/10095
renamed is_last_data to is_last_in_fec_set. However, the code shows that
this is actually meant to indicate where the serialized data is
complete:
https://github.com/solana-labs/solana/blob/420174d3d/ledger/src/shred.rs#L599-L600
https://github.com/solana-labs/solana/blob/420174d3d/ledger/src/shred.rs#L229-L231

There are multiple FEC sets for each `&[Entry]` serialized and this flag
does not represent shreds last in FEC sets (only the very last one by
overlap). So the name is wrong and confusing
---
 ledger/src/shred.rs | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/ledger/src/shred.rs b/ledger/src/shred.rs
index 013dc57a5a..d83416694a 100644
--- a/ledger/src/shred.rs
+++ b/ledger/src/shred.rs
@@ -201,7 +201,7 @@ impl Shred {
         index: u32,
         parent_offset: u16,
         data: Option<&[u8]>,
-        is_last_in_fec_set: bool,
+        is_last_data: bool,
         is_last_in_slot: bool,
         reference_tick: u8,
         version: u16,
@@ -226,7 +226,7 @@ impl Shred {
             size,
         };
 
-        if is_last_in_fec_set {
+        if is_last_data {
             data_header.flags |= DATA_COMPLETE_SHRED
         }
 
@@ -596,7 +596,7 @@ impl Shredder {
                         let fec_set_index =
                             shred_index - (i % MAX_DATA_SHREDS_PER_FEC_BLOCK as usize) as u32;
 
-                        let (is_last_in_fec_set, is_last_in_slot) = {
+                        let (is_last_data, is_last_in_slot) = {
                             if shred_index == last_shred_index {
                                 (true, is_last_in_slot)
                             } else {
@@ -609,7 +609,7 @@ impl Shredder {
                             shred_index,
                             (self.slot - self.parent_slot) as u16,
                             Some(shred_data),
-                            is_last_in_fec_set,
+                            is_last_data,
                             is_last_in_slot,
                             self.reference_tick,
                             self.version,
@@ -1082,7 +1082,7 @@ pub fn verify_test_data_shred(
     pk: &Pubkey,
     verify: bool,
     is_last_in_slot: bool,
-    is_last_in_fec_set: bool,
+    is_last_data: bool,
 ) {
     assert_eq!(shred.payload.len(), SHRED_PAYLOAD_SIZE);
     assert!(shred.is_data());
@@ -1095,7 +1095,7 @@ pub fn verify_test_data_shred(
     } else {
         assert!(!shred.last_in_slot());
     }
-    if is_last_in_fec_set {
+    if is_last_data {
         assert!(shred.data_complete());
     } else {
         assert!(!shred.data_complete());