chore: enable gocritic linter

.golangci.yml

@@ -7,6 +7,7 @@ linters:
     - govet
     - ineffassign
     - unconvert
+    - gocritic
 
 # See: https://golangci-lint.run/usage/formatters/
 formatters:

conn.go

@@ -808,7 +808,8 @@ optionLoop:
 
 	var err error
 	sd, explicitPreparedStatement := c.preparedStatements[sql]
-	if sd != nil || mode == QueryExecModeCacheStatement || mode == QueryExecModeCacheDescribe || mode == QueryExecModeDescribeExec {
+	switch {
+	case sd != nil || mode == QueryExecModeCacheStatement || mode == QueryExecModeCacheDescribe || mode == QueryExecModeDescribeExec:
 		if sd == nil {
 			sd, err = c.getStatementDescription(ctx, mode, sql)
 			if err != nil {
@@ -846,15 +847,15 @@ optionLoop:
 		} else {
 			rows.resultReader = c.pgConn.ExecStatement(ctx, sd, c.eqb.ParamValues, c.eqb.ParamFormats, resultFormats)
 		}
-	} else if mode == QueryExecModeExec {
+	case mode == QueryExecModeExec:
 		err := c.eqb.Build(c.typeMap, nil, args)
 		if err != nil {
 			rows.fatal(err)
 			return rows, rows.err
 		}
 
 		rows.resultReader = c.pgConn.ExecParams(ctx, sql, c.eqb.ParamValues, nil, c.eqb.ParamFormats, c.eqb.ResultFormats)
-	} else if mode == QueryExecModeSimpleProtocol {
+	case mode == QueryExecModeSimpleProtocol:
 		sql, err = c.sanitizeForSimpleQuery(sql, args...)
 		if err != nil {
 			rows.fatal(err)
@@ -872,7 +873,7 @@ optionLoop:
 		}
 
 		return rows, nil
-	} else {
+	default:
 		err = fmt.Errorf("unknown QueryExecMode: %v", mode)
 		rows.fatal(err)
 		return rows, rows.err

examples/chat/main.go

@@ -19,7 +19,12 @@ func main() {
 		os.Exit(1)
 	}
 
-	go listen()
+	go func() {
+		if err := listen(); err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		}
+	}()
 
 	fmt.Println(`Type a message and press enter.
 
@@ -47,25 +52,22 @@ Type "exit" to quit.`)
 	}
 }
 
-func listen() {
+func listen() error {
 	conn, err := pool.Acquire(context.Background())
 	if err != nil {
-		fmt.Fprintln(os.Stderr, "Error acquiring connection:", err)
-		os.Exit(1)
+		return fmt.Errorf("acquiring connection: %w", err)
 	}
 	defer conn.Release()
 
 	_, err = conn.Exec(context.Background(), "listen chat")
 	if err != nil {
-		fmt.Fprintln(os.Stderr, "Error listening to chat channel:", err)
-		os.Exit(1)
+		return fmt.Errorf("listening to chat channel: %w", err)
 	}
 
 	for {
 		notification, err := conn.Conn().WaitForNotification(context.Background())
 		if err != nil {
-			fmt.Fprintln(os.Stderr, "Error waiting for notification:", err)
-			os.Exit(1)
+			return fmt.Errorf("waiting for notification: %w", err)
 		}
 
 		fmt.Println("PID:", notification.PID, "Channel:", notification.Channel, "Payload:", notification.Payload)

pgconn/auth_scram.go

@@ -229,11 +229,12 @@ func (sc *scramClient) clientFirstMessage() []byte {
 
 	sc.clientFirstMessageBare = fmt.Appendf(nil, "n=,r=%s", sc.clientNonce)
 
-	if sc.authMechanism == scramSHA256PlusName {
+	switch {
+	case sc.authMechanism == scramSHA256PlusName:
 		sc.clientGS2Header = []byte("p=tls-server-end-point,,")
-	} else if sc.hasTLS {
+	case sc.hasTLS:
 		sc.clientGS2Header = []byte("y,,")
-	} else {
+	default:
 		sc.clientGS2Header = []byte("n,,")
 	}
 

pgconn/config.go

@@ -7,7 +7,6 @@ import (
 	"encoding/pem"
 	"errors"
 	"fmt"
-	"io"
 	"maps"
 	"math"
 	"net"
@@ -308,9 +307,7 @@ func ParseConfigWithOptions(connString string, options ParseConfigOptions) (*Con
 		User:                 settings["user"],
 		Password:             settings["password"],
 		RuntimeParams:        make(map[string]string),
-		BuildFrontend: func(r io.Reader, w io.Writer) *pgproto3.Frontend {
-			return pgproto3.NewFrontend(r, w)
-		},
+		BuildFrontend:        pgproto3.NewFrontend,
 		BuildContextWatcherHandler: func(pgConn *PgConn) ctxwatch.Handler {
 			return &DeadlineContextWatcherHandler{Conn: pgConn.conn}
 		},
@@ -643,8 +640,9 @@ func parseKeywordValueSettings(s string) (map[string]string, error) {
 
 		key = strings.Trim(s[:eqIdx], " \t\n\r\v\f")
 		s = strings.TrimLeft(s[eqIdx+1:], " \t\n\r\v\f")
-		if len(s) == 0 {
-		} else if s[0] != '\'' {
+		switch {
+		case len(s) == 0:
+		case s[0] != '\'':
 			end := 0
 			for ; end < len(s); end++ {
 				if asciiSpace[s[end]] == 1 {
@@ -657,11 +655,11 @@ func parseKeywordValueSettings(s string) (map[string]string, error) {
 					}
 				}
 			}
-			val = strings.Replace(strings.Replace(s[:end], "\\\\", "\\", -1), "\\'", "'", -1)
+			val = strings.ReplaceAll(strings.ReplaceAll(s[:end], "\\\\", "\\"), "\\'", "'")
 			// Consume the value and trim any subsequent whitespace so that
 			// multiple trailing spaces don't cause a spurious parse failure.
 			s = strings.TrimLeft(s[end:], " \t\n\r\v\f")
-		} else { // quoted string
+		default: // quoted string
 			s = s[1:]
 			end := 0
 			for ; end < len(s); end++ {
@@ -675,7 +673,7 @@ func parseKeywordValueSettings(s string) (map[string]string, error) {
 			if end == len(s) {
 				return nil, errors.New("unterminated quoted string in connection info string")
 			}
-			val = strings.Replace(strings.Replace(s[:end], "\\\\", "\\", -1), "\\'", "'", -1)
+			val = strings.ReplaceAll(strings.ReplaceAll(s[:end], "\\\\", "\\"), "\\'", "'")
 			// Consume the closing quote and any subsequent whitespace.
 			s = strings.TrimLeft(s[end+1:], " \t\n\r\v\f")
 		}

pgconn/errors.go

@@ -151,12 +151,13 @@ func (e *ParseConfigError) Unwrap() error {
 func normalizeTimeoutError(ctx context.Context, err error) error {
 	var netErr net.Error
 	if errors.As(err, &netErr) && netErr.Timeout() {
-		if ctx.Err() == context.Canceled {
+		switch ctx.Err() {
+		case context.Canceled:
 			// Since the timeout was caused by a context cancellation, the actual error is context.Canceled not the timeout error.
 			return context.Canceled
-		} else if ctx.Err() == context.DeadlineExceeded {
+		case context.DeadlineExceeded:
 			return &errTimeout{err: ctx.Err()}
-		} else {
+		default:
 			return &errTimeout{err: err}
 		}
 	}

pgconn/pgconn.go

@@ -1125,8 +1125,7 @@ func (pgConn *PgConn) WaitForNotification(ctx context.Context) error {
 			return normalizeTimeoutError(ctx, err)
 		}
 
-		switch msg.(type) {
-		case *pgproto3.NotificationResponse:
+		if _, ok := msg.(*pgproto3.NotificationResponse); ok {
 			return nil
 		}
 	}
@@ -1711,8 +1710,7 @@ func (rr *ResultReader) NextRow() bool {
 			return false
 		}
 
-		switch msg := msg.(type) {
-		case *pgproto3.DataRow:
+		if msg, ok := msg.(*pgproto3.DataRow); ok {
 			rr.rowValues = msg.Values
 			return true
 		}
@@ -2009,7 +2007,7 @@ func (pgConn *PgConn) EscapeString(s string) (string, error) {
 		return "", errors.New("EscapeString must be run with client_encoding=UTF8")
 	}
 
-	return strings.Replace(s, "'", "''", -1), nil
+	return strings.ReplaceAll(s, "'", "''"), nil
 }
 
 // CheckConn checks the underlying connection without writing any bytes. This is currently implemented by doing a read

pgconn/pgconn_test.go

@@ -8,7 +8,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"log"
 	"math"
 	"net"
 	"os"
@@ -4141,13 +4140,15 @@ func Example() {
 
 	pgConn, err := pgconn.Connect(ctx, os.Getenv("PGX_TEST_DATABASE"))
 	if err != nil {
-		log.Fatalln(err)
+		fmt.Fprintln(os.Stderr, err)
+		return
 	}
 	defer pgConn.Close(ctx)
 
 	result := pgConn.ExecParams(ctx, "select generate_series(1,3)", nil, nil, nil, nil).Read()
 	if result.Err != nil {
-		log.Fatalln(result.Err)
+		fmt.Fprintln(os.Stderr, result.Err)
+		return
 	}
 
 	for _, row := range result.Rows {

pgproto3/function_call.go

@@ -66,11 +66,12 @@ func (dst *FunctionCall) Decode(src []byte) error {
 		// As a special case, -1 indicates a NULL argument value. No value bytes follow in the NULL case.
 		argumentLength := int(int32(binary.BigEndian.Uint32(src[rp:])))
 		rp += 4
-		if argumentLength == -1 {
+		switch {
+		case argumentLength == -1:
 			arguments[i] = nil
-		} else if argumentLength < 0 {
+		case argumentLength < 0:
 			return &invalidMessageFormatErr{messageType: "FunctionCall"}
-		} else {
+		default:
 			if len(src[rp:]) < argumentLength {
 				return &invalidMessageFormatErr{messageType: "FunctionCall"}
 			}

pgtype/array.go

@@ -242,10 +242,11 @@ func parseUntypedTextArray(src string) (*untypedTextArray, error) {
 		return nil, fmt.Errorf("unexpected trailing data: %v", buf.String())
 	}
 
-	if len(dst.Elements) == 0 {
-	} else if len(explicitDimensions) > 0 {
+	switch {
+	case len(dst.Elements) == 0:
+	case len(explicitDimensions) > 0:
 		dst.Dimensions = explicitDimensions
-	} else {
+	default:
 		dst.Dimensions = implicitDimensions
 	}
 

pgtype/array_codec.go

@@ -391,10 +391,8 @@ func isRagged(slice reflect.Value) bool {
 	for i := range sliceLen {
 		if i == 0 {
 			innerLen = slice.Index(i).Len()
-		} else {
-			if slice.Index(i).Len() != innerLen {
-				return true
-			}
+		} else if slice.Index(i).Len() != innerLen {
+			return true
 		}
 		if isRagged(slice.Index(i)) {
 			return true

pgtype/bits.go

@@ -41,8 +41,7 @@ func (dst *Bits) Scan(src any) error {
 		return nil
 	}
 
-	switch src := src.(type) {
-	case string:
+	if src, ok := src.(string); ok {
 		return scanPlanTextAnyToBitsScanner{}.Scan([]byte(src), dst)
 	}
 
@@ -131,13 +130,11 @@ func (encodePlanBitsCodecText) Encode(value any, buf []byte) (newBuf []byte, err
 func (BitsCodec) PlanScan(m *Map, oid uint32, format int16, target any) ScanPlan {
 	switch format {
 	case BinaryFormatCode:
-		switch target.(type) {
-		case BitsScanner:
+		if _, ok := target.(BitsScanner); ok {
 			return scanPlanBinaryBitsToBitsScanner{}
 		}
 	case TextFormatCode:
-		switch target.(type) {
-		case BitsScanner:
+		if _, ok := target.(BitsScanner); ok {
 			return scanPlanTextAnyToBitsScanner{}
 		}
 	}
@@ -203,7 +200,7 @@ func (scanPlanTextAnyToBitsScanner) Scan(src []byte, dst any) error {
 		if b == '1' {
 			byteIdx := i / 8
 			bitIdx := uint(i % 8)
-			buf[byteIdx] = buf[byteIdx] | (128 >> bitIdx)
+			buf[byteIdx] |= 128 >> bitIdx
 		}
 	}
 

pgtype/bool.go

@@ -336,9 +336,9 @@ func planTextToBool(src []byte) (bool, error) {
 	s := string(bytes.ToLower(bytes.TrimSpace(src)))
 
 	switch {
-	case strings.HasPrefix("true", s), strings.HasPrefix("yes", s), s == "on", s == "1":
+	case strings.HasPrefix("true", s), strings.HasPrefix("yes", s), s == "on", s == "1": //nolint:gocritic // s is intentionally the prefix argument so partial inputs (t, tr, tru) also match.
 		return true, nil
-	case strings.HasPrefix("false", s), strings.HasPrefix("no", s), strings.HasPrefix("off", s), s == "0":
+	case strings.HasPrefix("false", s), strings.HasPrefix("no", s), strings.HasPrefix("off", s), s == "0": //nolint:gocritic // s is intentionally the prefix argument so partial inputs (f, fa, fal) also match.
 		return false, nil
 	default:
 		return false, fmt.Errorf("unknown boolean string representation %q", src)

pgtype/box.go

@@ -42,8 +42,7 @@ func (dst *Box) Scan(src any) error {
 		return nil
 	}
 
-	switch src := src.(type) {
-	case string:
+	if src, ok := src.(string); ok {
 		return scanPlanTextAnyToBoxScanner{}.Scan([]byte(src), dst)
 	}
 
@@ -131,13 +130,11 @@ func (encodePlanBoxCodecText) Encode(value any, buf []byte) (newBuf []byte, err
 func (BoxCodec) PlanScan(m *Map, oid uint32, format int16, target any) ScanPlan {
 	switch format {
 	case BinaryFormatCode:
-		switch target.(type) {
-		case BoxScanner:
+		if _, ok := target.(BoxScanner); ok {
 			return scanPlanBinaryBoxToBoxScanner{}
 		}
 	case TextFormatCode:
-		switch target.(type) {
-		case BoxScanner:
+		if _, ok := target.(BoxScanner); ok {
 			return scanPlanTextAnyToBoxScanner{}
 		}
 	}

pgtype/builtin_wrappers.go

@@ -822,7 +822,7 @@ func (a *anyMultiDimSliceArray) Index(i int) any {
 	for j := len(a.dims) - 1; j >= 0; j-- {
 		dimLen := int(a.dims[j].Length)
 		indexes[j] = i % dimLen
-		i = i / dimLen
+		i /= dimLen
 	}
 
 	v := a.slice

pgtype/circle.go

@@ -43,8 +43,7 @@ func (dst *Circle) Scan(src any) error {
 		return nil
 	}
 
-	switch src := src.(type) {
-	case string:
+	if src, ok := src.(string); ok {
 		return scanPlanTextAnyToCircleScanner{}.Scan([]byte(src), dst)
 	}
 
@@ -130,13 +129,11 @@ func (encodePlanCircleCodecText) Encode(value any, buf []byte) (newBuf []byte, e
 func (CircleCodec) PlanScan(m *Map, oid uint32, format int16, target any) ScanPlan {
 	switch format {
 	case BinaryFormatCode:
-		switch target.(type) {
-		case CircleScanner:
+		if _, ok := target.(CircleScanner); ok {
 			return scanPlanBinaryCircleToCircleScanner{}
 		}
 	case TextFormatCode:
-		switch target.(type) {
-		case CircleScanner:
+		if _, ok := target.(CircleScanner); ok {
 			return scanPlanTextAnyToCircleScanner{}
 		}
 	}