* Fixed returning io.EOF on rows.Next and rows.NextResultSet

* Added wrapping of errors from unary and stream results
* Added error throw on `database/sql.Conn.BeginTx()`, `*sql.Tx.ExecContext` and `*sql.Tx.QueryContext` if query mode is not `ydb.DataQueryMode`
* Added test for `database/sql` scan-query

Author: asmyasnikov

CHANGELOG.md

@@ -5,7 +5,9 @@
 * Refactored of applying grpc dial options with defaults
 * Added `trace.Driver.{OnBalancerDialEntrypoint,OnBalancerClusterDiscoveryAttempt}` trace events
 * Fixed compilation of package `internal/xresolver` with `google.golang.org/[email protected]`
+* Fixed returning `io.EOF` on `rows.Next` and `rows.NextResultSet`
 * Added wrapping of errors from unary and stream results
+* Added error throw on `database/sql.Conn.BeginTx()`, `*sql.Tx.ExecContext` and `*sql.Tx.QueryContext` if query mode is not `ydb.DataQueryMode`
 * Added test for `database/sql` scan-query
 
 ## v3.42.8

internal/xsql/badconn/badconn_go1.18.go

@@ -5,7 +5,6 @@ package badconn
 
 import (
 	"database/sql/driver"
-	"io"
 
 	"github.com/ydb-platform/ydb-go-sdk/v3/internal/xerrors"
 )
@@ -43,8 +42,6 @@ func Map(err error) error {
 	switch {
 	case err == nil:
 		return nil
-	case xerrors.Is(err, io.EOF):
-		return io.EOF
 	case xerrors.Is(err, driver.ErrBadConn):
 		return err
 	case xerrors.MustDeleteSession(err):

internal/xsql/conn.go

@@ -342,6 +342,10 @@ func (c *conn) BeginTx(ctx context.Context, txOptions driver.TxOptions) (_ drive
 	defer func() {
 		onDone(transaction, err)
 	}()
+	m := queryModeFromContext(ctx, c.defaultQueryMode)
+	if m != DataQueryMode {
+		return nil, badconn.Map(xerrors.WithStackTrace(fmt.Errorf("wrong query mode: %s", m.String())))
+	}
 	if !c.isReady() {
 		return nil, badconn.Map(xerrors.WithStackTrace(errNotReadyConn))
 	}

internal/xsql/rows.go

@@ -67,9 +67,15 @@ func (r *rows) ColumnTypeDatabaseTypeName(index int) string {
 	return yqlTypes[index]
 }
 
-func (r *rows) NextResultSet() error {
+func (r *rows) NextResultSet() (err error) {
+	defer func() {
+		if err != nil && xerrors.Is(err, io.EOF) {
+			// database/sql checks io.EOF with "==", not errors.Is(err, io.EOF)
+			err = io.EOF
+		}
+	}()
 	r.nextSet.Do(func() {})
-	err := r.result.NextResultSetErr(context.Background())
+	err = r.result.NextResultSetErr(context.Background())
 	if err != nil {
 		return badconn.Map(xerrors.WithStackTrace(err))
 	}
@@ -81,6 +87,12 @@ func (r *rows) HasNextResultSet() bool {
 }
 
 func (r *rows) Next(dst []driver.Value) (err error) {
+	defer func() {
+		if err != nil && xerrors.Is(err, io.EOF) {
+			// database/sql checks io.EOF with "==", not errors.Is(err, io.EOF)
+			err = io.EOF
+		}
+	}()
 	r.nextSet.Do(func() {
 		err = r.result.NextResultSetErr(context.Background())
 	})

internal/xsql/tx.go

@@ -3,6 +3,7 @@ package xsql
 import (
 	"context"
 	"database/sql/driver"
+	"fmt"
 
 	"github.com/ydb-platform/ydb-go-sdk/v3/internal/xcontext"
 	"github.com/ydb-platform/ydb-go-sdk/v3/internal/xerrors"
@@ -70,6 +71,10 @@ func (tx *tx) QueryContext(ctx context.Context, query string, args []driver.Name
 	defer func() {
 		onDone(err)
 	}()
+	m := queryModeFromContext(ctx, tx.conn.defaultQueryMode)
+	if m != DataQueryMode {
+		return nil, badconn.Map(xerrors.WithStackTrace(fmt.Errorf("wrong query mode: %s", m.String())))
+	}
 	var res result.Result
 	res, err = tx.tx.Execute(ctx,
 		query,
@@ -93,6 +98,10 @@ func (tx *tx) ExecContext(ctx context.Context, query string, args []driver.Named
 	defer func() {
 		onDone(err)
 	}()
+	m := queryModeFromContext(ctx, tx.conn.defaultQueryMode)
+	if m != DataQueryMode {
+		return nil, badconn.Map(xerrors.WithStackTrace(fmt.Errorf("wrong query mode: %s", m.String())))
+	}
 	_, err = tx.tx.Execute(ctx,
 		query,
 		toQueryParams(args),