database/sql: use slices to simplify the code

src/database/sql/fakedb_test.go

@@ -11,7 +11,7 @@ import (
 	"fmt"
 	"io"
 	"reflect"
-	"sort"
+	"slices"
 	"strconv"
 	"strings"
 	"sync"
@@ -120,12 +120,7 @@ type table struct {
 }
 
 func (t *table) columnIndex(name string) int {
-	for n, nname := range t.colname {
-		if name == nname {
-			return n
-		}
-	}
-	return -1
+	return slices.Index(t.colname, name)
 }
 
 type row struct {
@@ -217,15 +212,6 @@ func init() {
 	Register("test", fdriver)
 }
 
-func contains(list []string, y string) bool {
-	for _, x := range list {
-		if x == y {
-			return true
-		}
-	}
-	return false
-}
-
 type Dummy struct {
 	driver.Driver
 }
@@ -235,7 +221,7 @@ func TestDrivers(t *testing.T) {
 	Register("test", fdriver)
 	Register("invalid", Dummy{})
 	all := Drivers()
-	if len(all) < 2 || !sort.StringsAreSorted(all) || !contains(all, "test") || !contains(all, "invalid") {
+	if len(all) < 2 || !slices.IsSorted(all) || !slices.Contains(all, "test") || !slices.Contains(all, "invalid") {
 		t.Fatalf("Drivers = %v, want sorted list with at least [invalid, test]", all)
 	}
 }
@@ -345,10 +331,8 @@ func (db *fakeDB) columnType(table, column string) (typ string, ok bool) {
 	if !ok {
 		return
 	}
-	for n, cname := range t.colname {
-		if cname == column {
-			return t.coltype[n], true
-		}
+	if i := slices.Index(t.colname, column); i != -1 {
+		return t.coltype[i], true
 	}
 	return "", false
 }
@@ -823,6 +807,15 @@ func (s *fakeStmt) ExecContext(ctx context.Context, args []driver.NamedValue) (d
 	return nil, fmt.Errorf("fakedb: unimplemented statement Exec command type of %q", s.cmd)
 }
 
+func valueFromPlaceholderName(args []driver.NamedValue, name string) driver.Value {
+	for i := range args {
+		if args[i].Name == name {
+			return args[i].Value
+		}
+	}
+	return nil
+}
+
 // When doInsert is true, add the row to the table.
 // When doInsert is false do prep-work and error checking, but don't
 // actually add the row to the table.
@@ -857,11 +850,8 @@ func (s *fakeStmt) execInsert(args []driver.NamedValue, doInsert bool) (driver.R
 				val = args[argPos].Value
 			} else {
 				// Assign value from argument placeholder name.
-				for _, a := range args {
-					if a.Name == strvalue[1:] {
-						val = a.Value
-						break
-					}
+				if v := valueFromPlaceholderName(args, strvalue[1:]); v != nil {
+					val = v
 				}
 			}
 			argPos++
@@ -997,12 +987,8 @@ func (s *fakeStmt) QueryContext(ctx context.Context, args []driver.NamedValue) (
 				if wcol.Placeholder == "?" {
 					argValue = args[wcol.Ordinal-1].Value
 				} else {
-					// Assign arg value from placeholder name.
-					for _, a := range args {
-						if a.Name == wcol.Placeholder[1:] {
-							argValue = a.Value
-							break
-						}
+					if v := valueFromPlaceholderName(args, wcol.Placeholder[1:]); v != nil {
+						argValue = v
 					}
 				}
 				if fmt.Sprintf("%v", tcol) != fmt.Sprintf("%v", argValue) {

src/database/sql/sql.go

@@ -24,7 +24,7 @@ import (
 	"math/rand/v2"
 	"reflect"
 	"runtime"
-	"sort"
+	"slices"
 	"strconv"
 	"sync"
 	"sync/atomic"
@@ -69,7 +69,7 @@ func Drivers() []string {
 	for name := range drivers {
 		list = append(list, name)
 	}
-	sort.Strings(list)
+	slices.Sort(list)
 	return list
 }
 
@@ -3452,10 +3452,8 @@ func (r *Row) Scan(dest ...any) error {
 	// they were obtained from the network anyway) But for now we
 	// don't care.
 	defer r.rows.Close()
-	for _, dp := range dest {
-		if _, ok := dp.(*RawBytes); ok {
-			return errors.New("sql: RawBytes isn't allowed on Row.Scan")
-		}
+	if scanArgsContainRawBytes(dest) {
+		return errors.New("sql: RawBytes isn't allowed on Row.Scan")
 	}
 
 	if !r.rows.Next() {

src/database/sql/sql_test.go

@@ -40,14 +40,7 @@ func init() {
 		freedFrom[c] = s
 	}
 	putConnHook = func(db *DB, c *driverConn) {
-		idx := -1
-		for i, v := range db.freeConn {
-			if v == c {
-				idx = i
-				break
-			}
-		}
-		if idx >= 0 {
+		if slices.Contains(db.freeConn, c) {
 			// print before panic, as panic may get lost due to conflicting panic
 			// (all goroutines asleep) elsewhere, since we might not unlock
 			// the mutex in freeConn here.
@@ -291,7 +284,7 @@ func TestQuery(t *testing.T) {
 		{age: 2, name: "Bob"},
 		{age: 3, name: "Chris"},
 	}
-	if !reflect.DeepEqual(got, want) {
+	if !slices.Equal(got, want) {
 		t.Errorf("mismatch.\n got: %#v\nwant: %#v", got, want)
 	}
 
@@ -355,7 +348,7 @@ func TestQueryContext(t *testing.T) {
 		{age: 1, name: "Alice"},
 		{age: 2, name: "Bob"},
 	}
-	if !reflect.DeepEqual(got, want) {
+	if !slices.Equal(got, want) {
 		t.Errorf("mismatch.\n got: %#v\nwant: %#v", got, want)
 	}
 
@@ -540,7 +533,7 @@ func TestMultiResultSetQuery(t *testing.T) {
 		{age: 2, name: "Bob"},
 		{age: 3, name: "Chris"},
 	}
-	if !reflect.DeepEqual(got1, want1) {
+	if !slices.Equal(got1, want1) {
 		t.Errorf("mismatch.\n got1: %#v\nwant: %#v", got1, want1)
 	}
 
@@ -566,7 +559,7 @@ func TestMultiResultSetQuery(t *testing.T) {
 		{name: "Bob"},
 		{name: "Chris"},
 	}
-	if !reflect.DeepEqual(got2, want2) {
+	if !slices.Equal(got2, want2) {
 		t.Errorf("mismatch.\n got: %#v\nwant: %#v", got2, want2)
 	}
 	if rows.NextResultSet() {
@@ -614,7 +607,7 @@ func TestQueryNamedArg(t *testing.T) {
 	want := []row{
 		{age: 2, name: "Bob"},
 	}
-	if !reflect.DeepEqual(got, want) {
+	if !slices.Equal(got, want) {
 		t.Errorf("mismatch.\n got: %#v\nwant: %#v", got, want)
 	}
 
@@ -724,7 +717,7 @@ func TestRowsColumns(t *testing.T) {
 		t.Fatalf("Columns: %v", err)
 	}
 	want := []string{"age", "name"}
-	if !reflect.DeepEqual(cols, want) {
+	if !slices.Equal(cols, want) {
 		t.Errorf("got %#v; want %#v", cols, want)
 	}
 	if err := rows.Close(); err != nil {
@@ -827,7 +820,7 @@ func TestQueryRow(t *testing.T) {
 		t.Fatalf("photo QueryRow+Scan: %v", err)
 	}
 	want := []byte("APHOTO")
-	if !reflect.DeepEqual(photo, want) {
+	if !slices.Equal(photo, want) {
 		t.Errorf("photo = %q; want %q", photo, want)
 	}
 }