Use std errors instead of golang.org/x/xerrors

New error functionality was introduced in Go 1.13. pgconn only
officially supports 1.15+. Transitional xerrors package can now be
removed.

auth_scram.go

@@ -18,13 +18,13 @@ import (
 	"crypto/rand"
 	"crypto/sha256"
 	"encoding/base64"
+	"errors"
 	"fmt"
 	"strconv"
 
 	"github.com/jackc/pgproto3/v2"
 	"golang.org/x/crypto/pbkdf2"
 	"golang.org/x/text/secure/precis"
-	errors "golang.org/x/xerrors"
 )
 
 const clientNonceLen = 18
@@ -192,12 +192,12 @@ func (sc *scramClient) recvServerFirstMessage(serverFirstMessage []byte) error {
 	var err error
 	sc.salt, err = base64.StdEncoding.DecodeString(string(saltStr))
 	if err != nil {
-		return errors.Errorf("invalid SCRAM salt received from server: %w", err)
+		return fmt.Errorf("invalid SCRAM salt received from server: %w", err)
 	}
 
 	sc.iterations, err = strconv.Atoi(string(iterationsStr))
 	if err != nil || sc.iterations <= 0 {
-		return errors.Errorf("invalid SCRAM iteration count received from server: %w", err)
+		return fmt.Errorf("invalid SCRAM iteration count received from server: %w", err)
 	}
 
 	if !bytes.HasPrefix(sc.clientAndServerNonce, sc.clientNonce) {

config.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"crypto/tls"
 	"crypto/x509"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -20,7 +21,6 @@ import (
 	"github.com/jackc/pgpassfile"
 	"github.com/jackc/pgproto3/v2"
 	"github.com/jackc/pgservicefile"
-	errors "golang.org/x/xerrors"
 )
 
 type AfterConnectFunc func(ctx context.Context, pgconn *PgConn) error
@@ -409,7 +409,7 @@ func parseURLSettings(connString string) (map[string]string, error) {
 		}
 		h, p, err := net.SplitHostPort(host)
 		if err != nil {
-			return nil, errors.Errorf("failed to split host:port in '%s', err: %w", host, err)
+			return nil, fmt.Errorf("failed to split host:port in '%s', err: %w", host, err)
 		}
 		hosts = append(hosts, h)
 		ports = append(ports, p)
@@ -617,7 +617,7 @@ func configTLS(settings map[string]string) ([]*tls.Config, error) {
 		caPath := sslrootcert
 		caCert, err := ioutil.ReadFile(caPath)
 		if err != nil {
-			return nil, errors.Errorf("unable to read CA file: %w", err)
+			return nil, fmt.Errorf("unable to read CA file: %w", err)
 		}
 
 		if !caCertPool.AppendCertsFromPEM(caCert) {
@@ -635,7 +635,7 @@ func configTLS(settings map[string]string) ([]*tls.Config, error) {
 	if sslcert != "" && sslkey != "" {
 		cert, err := tls.LoadX509KeyPair(sslcert, sslkey)
 		if err != nil {
-			return nil, errors.Errorf("unable to read cert: %w", err)
+			return nil, fmt.Errorf("unable to read cert: %w", err)
 		}
 
 		tlsConfig.Certificates = []tls.Certificate{cert}

errors.go

@@ -2,13 +2,12 @@ package pgconn
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"net"
 	"net/url"
 	"regexp"
 	"strings"
-
-	errors "golang.org/x/xerrors"
 )
 
 // SafeToRetry checks if the err is guaranteed to have occurred before sending any data to the server.

go.mod

@@ -12,5 +12,4 @@ require (
 	github.com/stretchr/testify v1.5.1
 	golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9
 	golang.org/x/text v0.3.3
-	golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7
 )

pgconn.go

@@ -6,6 +6,8 @@ import (
 	"crypto/tls"
 	"encoding/binary"
 	"encoding/hex"
+	"errors"
+	"fmt"
 	"io"
 	"math"
 	"net"
@@ -16,7 +18,6 @@ import (
 	"github.com/jackc/pgconn/internal/ctxwatch"
 	"github.com/jackc/pgio"
 	"github.com/jackc/pgproto3/v2"
-	errors "golang.org/x/xerrors"
 )
 
 const (
@@ -1043,7 +1044,7 @@ func (pgConn *PgConn) execExtendedPrefix(ctx context.Context, paramValues [][]by
 	}
 
 	if len(paramValues) > math.MaxUint16 {
-		result.concludeCommand(nil, errors.Errorf("extended protocol limited to %v parameters", math.MaxUint16))
+		result.concludeCommand(nil, fmt.Errorf("extended protocol limited to %v parameters", math.MaxUint16))
 		result.closed = true
 		pgConn.unlock()
 		return result

pgconn_test.go

@@ -5,6 +5,7 @@ import (
 	"compress/gzip"
 	"context"
 	"crypto/tls"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -17,12 +18,9 @@ import (
 	"testing"
 	"time"
 
-	"github.com/jackc/pgmock"
-
 	"github.com/jackc/pgconn"
+	"github.com/jackc/pgmock"
 	"github.com/jackc/pgproto3/v2"
-	errors "golang.org/x/xerrors"
-
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )