From 1482d7f011e3bb417404c6ece6dfad752b1299e7 Mon Sep 17 00:00:00 2001
From: Po-Chuan Hsieh <sunpoet@sunpoet.net>
Date: Tue, 7 Jan 2025 10:02:48 +0800
Subject: [PATCH] Fix build with -Wrange-loop-construct

db/db_impl/db_impl_write.cc:208:19: error: loop variable '[cf_id, stat]' creates a copy from type 'const value_type' (aka 'const pair<const unsigned int, rocksdb::WriteBatchWithIndex::CFStat>') [-Werror,-Wrange-loop-construct]
  208 |   for (const auto [cf_id, stat] : wbwi->GetCFStats()) {
      |                   ^
db/db_impl/db_impl_write.cc:208:8: note: use reference type 'const value_type &' (aka 'const pair<const unsigned int, rocksdb::WriteBatchWithIndex::CFStat> &') to prevent copying
  208 |   for (const auto [cf_id, stat] : wbwi->GetCFStats()) {
      |        ^~~~~~~~~~~~~~~~~~~~~~~~~~
      |                   &
1 error generated.
---
 db/db_impl/db_impl_write.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/db/db_impl/db_impl_write.cc b/db/db_impl/db_impl_write.cc
index 39b03dc7e3a..cda2707ef16 100644
--- a/db/db_impl/db_impl_write.cc
+++ b/db/db_impl/db_impl_write.cc
@@ -205,7 +205,7 @@ Status DBImpl::IngestWBWI(std::shared_ptr<WriteBatchWithIndex> wbwi,
   ColumnFamilySet* cf_set = versions_->GetColumnFamilySet();
 
   // Create WBWIMemTables
-  for (const auto [cf_id, stat] : wbwi->GetCFStats()) {
+  for (const auto& [cf_id, stat] : wbwi->GetCFStats()) {
     ColumnFamilyData* cfd = cf_set->GetColumnFamily(cf_id);
     if (!cfd) {
       if (ignore_missing_cf) {