exp/sql: close Rows on EOF

Fixes #2624

R=rsc
CC=golang-dev
https://golang.org/cl/5530068

src/pkg/exp/sql/fakedb_test.go

@@ -110,25 +110,34 @@ func init() {
 
 // Supports dsn forms:
 //    <dbname>
-//    <dbname>;wipe
+//    <dbname>;<opts>  (no currently supported options)
 func (d *fakeDriver) Open(dsn string) (driver.Conn, error) {
-	d.mu.Lock()
-	defer d.mu.Unlock()
-	d.openCount++
-	if d.dbs == nil {
-		d.dbs = make(map[string]*fakeDB)
-	}
 	parts := strings.Split(dsn, ";")
 	if len(parts) < 1 {
 		return nil, errors.New("fakedb: no database name")
 	}
 	name := parts[0]
+
+	db := d.getDB(name)
+
+	d.mu.Lock()
+	d.openCount++
+	d.mu.Unlock()
+	return &fakeConn{db: db}, nil
+}
+
+func (d *fakeDriver) getDB(name string) *fakeDB {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	if d.dbs == nil {
+		d.dbs = make(map[string]*fakeDB)
+	}
 	db, ok := d.dbs[name]
 	if !ok {
 		db = &fakeDB{name: name}
 		d.dbs[name] = db
 	}
-	return &fakeConn{db: db}, nil
+	return db
 }
 
 func (db *fakeDB) wipe() {

src/pkg/exp/sql/sql.go

@@ -549,8 +549,8 @@ func (s *Stmt) Exec(args ...interface{}) (Result, error) {
 // statement, a function to call to release the connection, and a
 // statement bound to that connection.
 func (s *Stmt) connStmt() (ci driver.Conn, releaseConn func(), si driver.Stmt, err error) {
-	if s.stickyErr != nil {
+	if err = s.stickyErr; err != nil {
-		return nil, nil, nil, s.stickyErr
+		return
 	}
 	s.mu.Lock()
 	if s.closed {
@@ -726,6 +726,9 @@ func (rs *Rows) Next() bool {
 		rs.lastcols = make([]interface{}, len(rs.rowsi.Columns()))
 	}
 	rs.lasterr = rs.rowsi.Next(rs.lastcols)
+	if rs.lasterr == io.EOF {
+		rs.Close()
+	}
 	return rs.lasterr == nil
 }
 

src/pkg/exp/sql/sql_test.go

@@ -10,8 +10,10 @@ import (
 	"testing"
 )
 
+const fakeDBName = "foo"
+
 func newTestDB(t *testing.T, name string) *DB {
-	db, err := Open("test", "foo")
+	db, err := Open("test", fakeDBName)
 	if err != nil {
 		t.Fatalf("Open: %v", err)
 	}
@@ -73,6 +75,12 @@ func TestQuery(t *testing.T) {
 	if !reflect.DeepEqual(got, want) {
 		t.Logf(" got: %#v\nwant: %#v", got, want)
 	}
+
+	// And verify that the final rows.Next() call, which hit EOF,
+	// also closed the rows connection.
+	if n := len(db.freeConn); n != 1 {
+		t.Errorf("free conns after query hitting EOF = %d; want 1", n)
+	}
 }
 
 func TestRowsColumns(t *testing.T) {