fix null stats provider crash when build store is not configured (#875)v5.7.25-pre0

- When build store is not configured, `m_BuildCidStore` is null but was unconditionally added as a stats provider, causing a null pointer dereference crash in `StatsReporter::ReportStats`
- Added a null guard in `AddProvider` to reject null pointers defensively
- Added a conditional check at the call site in `InitializeStructuredCache`

2 files changed, 8 insertions, 1 deletions

diff --git a/src/zenserver/stats/statsreporter.cpp b/src/zenserver/stats/statsreporter.cpp
index a1926eba4..ff055cf18 100644
--- a/src/zenserver/stats/statsreporter.cpp
+++ b/src/zenserver/stats/statsreporter.cpp
@@ -40,6 +40,10 @@ StatsReporter::Shutdown()
 void
 StatsReporter::AddProvider(StatsProvider* Provider)
 {
+	if (!Provider)
+	{
+		return;
+	}
 	RwLock::ExclusiveLockScope _(m_Lock);
 	m_Providers.push_back(Provider);
 }
diff --git a/src/zenserver/storage/zenstorageserver.cpp b/src/zenserver/storage/zenstorageserver.cpp
index f5ede5692..d51a425a9 100644
--- a/src/zenserver/storage/zenstorageserver.cpp
+++ b/src/zenserver/storage/zenstorageserver.cpp
@@ -697,7 +697,10 @@ ZenStorageServer::InitializeStructuredCache(const ZenStorageServerConfig& Server
 
 	m_StatsReporter.AddProvider(m_CacheStore.Get());
 	m_StatsReporter.AddProvider(m_CidStore.get());
-	m_StatsReporter.AddProvider(m_BuildCidStore.get());
+	if (m_BuildCidStore)
+	{
+		m_StatsReporter.AddProvider(m_BuildCidStore.get());
+	}
 }
 
 void