FIX: Fix potential data corruption in DbnFileStore

threecgreen · threecgreen · commit fd4be2634357 · 2025-07-22T13:43:49.000Z
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+## 0.39.1 - TBD
+
+### Bug fixes
+- Fixed potential corrupted data in `DbnFileStore::Replay`
+
 ## 0.39.0 - 2025-07-15
 
 ### Breaking changes
diff --git a/src/dbn_decoder.cpp b/src/dbn_decoder.cpp
@@ -311,7 +311,7 @@ const databento::Record* DbnDecoder::DecodeRecord() {
     }
   }
   current_record_ = Record{BufferRecordHeader()};
-  buffer_.Consume(current_record_.Size());
+  buffer_.ConsumeNoShift(current_record_.Size());
   current_record_ = DbnDecoder::DecodeRecordCompat(
       version_, upgrade_policy_, ts_out_, &compat_buffer_, current_record_);
   return &current_record_;
diff --git a/src/live_blocking.cpp b/src/live_blocking.cpp
@@ -190,11 +190,10 @@ const databento::Record* LiveBlocking::NextRecord(
   }
   current_record_ = Record{BufferRecordHeader()};
   const auto bytes_to_consume = current_record_.Size();
+  buffer_.ConsumeNoShift(bytes_to_consume);
   current_record_ =
       DbnDecoder::DecodeRecordCompat(version_, upgrade_policy_, send_ts_out_,
                                      &compat_buffer_, current_record_);
-  // Can't consume til after upgrade as Consume may shift
-  buffer_.Consume(bytes_to_consume);
   return &current_record_;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -311,7 +311,7 @@ const databento::Record* DbnDecoder::DecodeRecord() {`
`311`	`311`	`}`
`312`	`312`	`}`
`313`	`313`	`current_record_ = Record{BufferRecordHeader()};`
`314`		`- buffer_.Consume(current_record_.Size());`
	`314`	`+ buffer_.ConsumeNoShift(current_record_.Size());`
`315`	`315`	`current_record_ = DbnDecoder::DecodeRecordCompat(`
`316`	`316`	`version_, upgrade_policy_, ts_out_, &compat_buffer_, current_record_);`
`317`	`317`	`return &current_record_;`
Original file line number	Diff line number	Diff line change
`@@ -190,11 +190,10 @@ const databento::Record* LiveBlocking::NextRecord(`
`190`	`190`	`}`
`191`	`191`	`current_record_ = Record{BufferRecordHeader()};`
`192`	`192`	`const auto bytes_to_consume = current_record_.Size();`
	`193`	`+ buffer_.ConsumeNoShift(bytes_to_consume);`
`193`	`194`	`current_record_ =`
`194`	`195`	`DbnDecoder::DecodeRecordCompat(version_, upgrade_policy_, send_ts_out_,`
`195`	`196`	`&compat_buffer_, current_record_);`
`196`		`- // Can't consume til after upgrade as Consume may shift`
`197`		`- buffer_.Consume(bytes_to_consume);`
`198`	`197`	`return &current_record_;`
`199`	`198`	`}`
`200`	`199`