Merge the latest enhancements from trunk into the right-join branch.

FossilOrigin-Name: b3e57ba120067c79e0398e39da9f00ecb11a5e18c36479da4c36a39e88a78a27

src/btree.c

@@ -8491,7 +8491,7 @@ static int balance_nonroot(
     iOvflSpace += sz;
     assert( sz<=pBt->maxLocal+23 );
     assert( iOvflSpace <= (int)pBt->pageSize );
-    for(k=0; b.ixNx[k]<=i && ALWAYS(k<NB*2); k++){}
+    for(k=0; b.ixNx[k]<=j && ALWAYS(k<NB*2); k++){}
     pSrcEnd = b.apEnd[k];
     if( SQLITE_WITHIN(pSrcEnd, pCell, pCell+sz) ){
       rc = SQLITE_CORRUPT_BKPT;

src/malloc.c

@@ -750,8 +750,9 @@ char *sqlite3DbSpanDup(sqlite3 *db, const char *zStart, const char *zEnd){
 ** Free any prior content in *pz and replace it with a copy of zNew.
 */
 void sqlite3SetString(char **pz, sqlite3 *db, const char *zNew){
+  char *z = sqlite3DbStrDup(db, zNew);
   sqlite3DbFree(db, *pz);
-  *pz = sqlite3DbStrDup(db, zNew);
+  *pz = z;
 }
 
 /*