https://sqlite.org/src/info/b2ce5ed175cb5029
https://sqlite.org/src/info/6e4a5f22811bcd14
https://sqlite.org/src/info/516ca8945150bdc1
https://sqlite.org/src/info/e1724f1d618cfbcf
https://sqlite.org/src/info/c621fc668c6538f9
https://sqlite.org/src/info/c509d8a8aebe0da4
https://sqlite.org/src/info/a9b90aa12eecdd9f

--- /sqlite3.c
+++ /sqlite3.c
@@ -67472,10 +67472,9 @@
       rc = newDatabase(pBt);
       pBt->nPage = get4byte(28 + pBt->pPage1->aData);
 
-      /* The database size was written into the offset 28 of the header
-      ** when the transaction started, so we know that the value at offset
-      ** 28 is nonzero. */
-      assert( pBt->nPage>0 );
+      /* pBt->nPage might be zero if the database was corrupt when 
+      ** the transaction was started. Otherwise, it must be at least 1.  */
+      assert( CORRUPT_DB || pBt->nPage>0 );
     }
     sqlite3BtreeLeave(p);
   }
@@ -70825,6 +70824,7 @@
     u16 maskPage = pOld->maskPage;
     u8 *piCell = aData + pOld->cellOffset;
     u8 *piEnd;
+    VVA_ONLY( int nCellAtStart = b.nCell; )
 
     /* Verify that all sibling pages are of the same "type" (table-leaf,
     ** table-interior, index-leaf, or index-interior).
@@ -70853,6 +70853,10 @@
     */
     memset(&b.szCell[b.nCell], 0, sizeof(b.szCell[0])*(limit+pOld->nOverflow));
     if( pOld->nOverflow>0 ){
+      if( limit<pOld->aiOvfl[0] ){
+        rc = SQLITE_CORRUPT_BKPT;
+        goto balance_cleanup;
+      }
       limit = pOld->aiOvfl[0];
       for(j=0; j<limit; j++){
         b.apCell[b.nCell] = aData + (maskPage & get2byteAligned(piCell));
@@ -70872,6 +70876,7 @@
       piCell += 2;
       b.nCell++;
     }
+    assert( (b.nCell-nCellAtStart)==(pOld->nCell+pOld->nOverflow) );
 
     cntOld[i] = b.nCell;
     if( i<nOld-1 && !leafData){
@@ -83747,7 +83752,7 @@
     ** is clear. Otherwise, if this is an ephemeral cursor created by 
     ** OP_OpenDup, the cursor will not be closed and will still be part
     ** of a BtShared.pCursor list.  */
-    p->apCsr[iCur]->isEphemeral = 0;
+    if( p->apCsr[iCur]->pBtx==0 ) p->apCsr[iCur]->isEphemeral = 0;
     sqlite3VdbeFreeCursor(p, p->apCsr[iCur]);
     p->apCsr[iCur] = 0;
   }
@@ -87258,7 +87263,10 @@
   if( pCx ){
     /* If the ephermeral table is already open, erase all existing content
     ** so that the table is empty again, rather than creating a new table. */
-    rc = sqlite3BtreeClearTable(pCx->pBtx, pCx->pgnoRoot, 0);
+    assert( pCx->isEphemeral );
+    if( pCx->pBtx ){
+      rc = sqlite3BtreeClearTable(pCx->pBtx, pCx->pgnoRoot, 0);
+    }
   }else{
     pCx = allocateCursor(p, pOp->p1, pOp->p2, -1, CURTYPE_BTREE);
     if( pCx==0 ) goto no_mem;
@@ -95979,7 +95987,9 @@
 #ifndef SQLITE_OMIT_WINDOWFUNC
         if( pExpr->y.pWin ){
           Select *pSel = pNC->pWinSelect;
-          sqlite3WindowUpdate(pParse, pSel->pWinDefn, pExpr->y.pWin, pDef);
+          if( IN_RENAME_OBJECT==0 ){
+            sqlite3WindowUpdate(pParse, pSel->pWinDefn, pExpr->y.pWin, pDef);
+          }
           sqlite3WalkExprList(pWalker, pExpr->y.pWin->pPartition);
           sqlite3WalkExprList(pWalker, pExpr->y.pWin->pOrderBy);
           sqlite3WalkExpr(pWalker, pExpr->y.pWin->pFilter);
@@ -174132,7 +174142,7 @@
     }
     p->iOff += fts3GetVarint32(&p->aNode[p->iOff], &nSuffix);
 
-    if( nPrefix>p->iOff || nSuffix>p->nNode-p->iOff ){
+    if( nPrefix>p->term.n || nSuffix>p->nNode-p->iOff || nSuffix==0 ){
       return FTS_CORRUPT_VTAB;
     }
     blobGrowBuffer(&p->term, nPrefix+nSuffix, &rc);
@@ -174151,7 +174161,7 @@
     }
   }
 
-  assert( p->iOff<=p->nNode );
+  assert_fts3_nc( p->iOff<=p->nNode );
   return rc;
 }
 
@@ -204287,7 +204297,11 @@
     i64 iOff = *piOff;
     int iVal;
     fts5FastGetVarint32(a, i, iVal);
-    if( iVal==1 ){
+    if( iVal<=1 ){
+      if( iVal==0 ){
+        *pi = i;
+        return 0;
+      }
       fts5FastGetVarint32(a, i, iVal);
       iOff = ((i64)iVal) << 32;
       fts5FastGetVarint32(a, i, iVal);