leave legacy files so we can switch back to older version without crashing

1 files changed, 13 insertions, 5 deletions

diff --git a/zenstore/compactcas.cpp b/zenstore/compactcas.cpp
index c2ca5b78f..0c4a84dd1 100644
--- a/zenstore/compactcas.cpp
+++ b/zenstore/compactcas.cpp
@@ -594,15 +594,23 @@ namespace {
 				}
 			}
 		}
+
+		BlockFile.Close();
 		LegacyCasLog.Close();
 		CasLog.Close();
 
 		if (CleanSource)
 		{
-			std::filesystem::remove(LegacyLogPath);
-			BlockFile.Close();
-			std::filesystem::remove(LegacySobsPath);
-			std::filesystem::remove(LegacySidxPath);
+			// Older versions of CasContainerStrategy expects the legacy files to exist if it can find
+			// a CAS manifest and crashes on startup if they don't.
+			// In order to not break startup when switching back an older version, lets just reset
+			// the legacy data files to zero length.
+			BasicFile LegacyLog;
+			LegacyLog.Open(LegacyLogPath, BasicFile::EMode::kTruncate);
+			BasicFile LegacySobs;
+			LegacySobs.Open(LegacySobsPath, BasicFile::EMode::kTruncate);
+			BasicFile LegacySidx;
+			LegacySidx.Open(LegacySidxPath, BasicFile::EMode::kTruncate);
 		}
 		return Result;
 	}
@@ -1493,7 +1501,7 @@ CasContainerStrategy::OpenContainer(bool IsNewStore)
 		MakeSnapshot = !LogEntries.empty();
 	}
 
-	if (std::filesystem::is_regular_file(LegacyLogPath))
+	if (std::filesystem::is_regular_file(LegacyLogPath) && std::filesystem::file_size(LegacyLogPath) > 0)
 	{
 		std::unordered_set<IoHash, IoHash::Hasher> ExistingChunks;
 		ExistingChunks.reserve(m_LocationMap.size());