onError = pTab->keyConf;
    if( overrideError!=OE_Default ){
      onError = overrideError;
    }else if( onError==OE_Default ){
      onError = OE_Abort;
    }

    if( isUpdate ){
      /* pkChng!=0 does not mean that the rowid has changed, only that
      ** it might have changed.  Skip the conflict logic below if the rowid
      ** is unchanged. */
      sqlite3VdbeAddOp3(v, OP_Eq, regNewData, addrRowidOk, regOldData);
      sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
      VdbeCoverage(v);
    }

    /* figure out whether or not upsert applies in this case */
    if( pUpsert && pUpsert->pUpsertIdx==0 ){
      if( pUpsert->pUpsertSet==0 ){
        onError = OE_Ignore;  /* DO NOTHING is the same as INSERT OR IGNORE */
      }else{
        onError = OE_Update;  /* DO UPDATE */
      }
................................................................................
    assert( OE_Rollback<OE_Replace );
    if( onError>=OE_Replace
     && onError!=overrideError
     && pTab->pIndex
    ){
      sAddr.ipkTop = sqlite3VdbeAddOp0(v, OP_Goto)+1;
    }










    /* Check to see if the new rowid already exists in the table.  Skip
    ** the following conflict logic if it does not. */
    VdbeNoopComment((v, "uniqueness check for ROWID"));
    sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, addrRowidOk, regNewData);
    VdbeCoverage(v);

    onError = pTab->keyConf;
    if( overrideError!=OE_Default ){
      onError = overrideError;
    }else if( onError==OE_Default ){
      onError = OE_Abort;
    }










    /* figure out whether or not upsert applies in this case */
    if( pUpsert && pUpsert->pUpsertIdx==0 ){
      if( pUpsert->pUpsertSet==0 ){
        onError = OE_Ignore;  /* DO NOTHING is the same as INSERT OR IGNORE */
      }else{
        onError = OE_Update;  /* DO UPDATE */
      }
................................................................................
    assert( OE_Rollback<OE_Replace );
    if( onError>=OE_Replace
     && onError!=overrideError
     && pTab->pIndex
    ){
      sAddr.ipkTop = sqlite3VdbeAddOp0(v, OP_Goto)+1;
    }

    if( isUpdate ){
      /* pkChng!=0 does not mean that the rowid has changed, only that
      ** it might have changed.  Skip the conflict logic below if the rowid
      ** is unchanged. */
      sqlite3VdbeAddOp3(v, OP_Eq, regNewData, addrRowidOk, regOldData);
      sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
      VdbeCoverage(v);
    }

    /* Check to see if the new rowid already exists in the table.  Skip
    ** the following conflict logic if it does not. */
    VdbeNoopComment((v, "uniqueness check for ROWID"));
    sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, addrRowidOk, regNewData);
    VdbeCoverage(v);

  CREATE INDEX t15c ON t15(c);
  INSERT INTO t15(a,b)
   VALUES(5,'zyx'),(15,'wvu'),(25,'tsr'),(35,'qpo');
  UPDATE t15 SET c=printf("y%d",a) WHERE c IS NULL;
  SELECT a,b,c,'|' FROM t15 ORDER BY a;
} {5 zyx y5 | 10 abc y10 | 15 wvu y15 | 20 def y20 | 25 tsr y25 | 30 ghi y30 | 35 qpo y35 |}












finish_test

  CREATE INDEX t15c ON t15(c);
  INSERT INTO t15(a,b)
   VALUES(5,'zyx'),(15,'wvu'),(25,'tsr'),(35,'qpo');
  UPDATE t15 SET c=printf("y%d",a) WHERE c IS NULL;
  SELECT a,b,c,'|' FROM t15 ORDER BY a;
} {5 zyx y5 | 10 abc y10 | 15 wvu y15 | 20 def y20 | 25 tsr y25 | 30 ghi y30 | 35 qpo y35 |}

# Unreleased bug in UPDATE caused by the UPSERT changes.
# Found by OSSFuzz as soon as the UPSERT changes landed on trunk.
# Never released into the wild.  2018-04-19.
#
do_execsql_test update-16.1 {
  CREATE TABLE t16(a INTEGER PRIMARY KEY ON CONFLICT REPLACE, b UNIQUE);
  INSERT INTO t16(a,b) VALUES(1,2),(3,4),(5,6);
  UPDATE t16 SET a=a;
  SELECT * FROM t16 ORDER BY +a;
} {1 2 3 4 5 6}

finish_test