fix(sync): sending snapshot

include/libs/sync/sync.h

@@ -91,6 +91,7 @@ typedef struct SSnapshot {
   void*     data;
   SyncIndex lastApplyIndex;
   SyncTerm  lastApplyTerm;
+  SyncIndex lastConfigIndex;
 } SSnapshot;
 
 typedef struct SSyncFSM {

source/libs/sync/src/syncAppendEntries.c

@@ -438,9 +438,12 @@ static bool syncNodeOnAppendEntriesLogOK(SSyncNode* pSyncNode, SyncAppendEntries
     return true;
   }
 
-  SyncTerm  myPreLogTerm = syncNodeGetPreTerm(pSyncNode, pMsg->prevLogIndex + 1);
   SyncIndex myLastIndex = syncNodeGetLastIndex(pSyncNode);
+  if (pMsg->prevLogIndex > myLastIndex) {
+    return false;
+  }
 
+  SyncTerm myPreLogTerm = syncNodeGetPreTerm(pSyncNode, pMsg->prevLogIndex + 1);
   if (pMsg->prevLogIndex <= myLastIndex && pMsg->prevLogTerm == myPreLogTerm) {
     return true;
   }

source/libs/sync/src/syncRaftLog.c

@@ -198,7 +198,7 @@ static int32_t raftLogGetEntry(struct SSyncLogStore* pLogStore, SyncIndex index,
 
   } else {
     // index not in range
-    code = -2;
+    code = 0;
   }
 
   return code;