Upgrade to golangci-lint v2 (#1008)

internal/assert/assertions.go

@@ -1,3 +1,4 @@
+// Package assert provides assertion functions for unit testing.
 package assert
 
 import (
@@ -9,66 +10,67 @@ import (
 )
 
 // True asserts that an expression is true.
-func True(t testing.TB, ok bool, msgAndArgs ...any) {
+func True(tb testing.TB, ok bool, msgAndArgs ...any) {
+	tb.Helper()
 	if ok {
 		return
 	}
-	t.Helper()
-	t.Fatal(formatMsgAndArgs("Expected expression to be true", msgAndArgs...))
+	tb.Fatal(formatMsgAndArgs("Expected expression to be true", msgAndArgs...))
 }
 
 // False asserts that an expression is false.
-func False(t testing.TB, ok bool, msgAndArgs ...any) {
+func False(tb testing.TB, ok bool, msgAndArgs ...any) {
+	tb.Helper()
 	if !ok {
 		return
 	}
-	t.Helper()
-	t.Fatal(formatMsgAndArgs("Expected expression to be false", msgAndArgs...))
+	tb.Fatal(formatMsgAndArgs("Expected expression to be false", msgAndArgs...))
 }
 
 // Equal asserts that "expected" and "actual" are equal.
-func Equal[T any](t testing.TB, expected, actual T, msgAndArgs ...any) {
+func Equal[T any](tb testing.TB, expected, actual T, msgAndArgs ...any) {
+	tb.Helper()
 	if objectsAreEqual(expected, actual) {
 		return
 	}
-	t.Helper()
 	msg := formatMsgAndArgs("Expected values to be equal:", msgAndArgs...)
-	t.Fatalf("%s\n%s", msg, diff(expected, actual))
+	tb.Fatalf("%s\n%s", msg, diff(expected, actual))
 }
 
 // Error asserts that an error is not nil.
-func Error(t testing.TB, err error, msgAndArgs ...any) {
+func Error(tb testing.TB, err error, msgAndArgs ...any) {
+	tb.Helper()
 	if err != nil {
 		return
 	}
-	t.Helper()
-	t.Fatal(formatMsgAndArgs("Expected an error", msgAndArgs...))
+	tb.Fatal(formatMsgAndArgs("Expected an error", msgAndArgs...))
 }
 
 // NoError asserts that an error is nil.
-func NoError(t testing.TB, err error, msgAndArgs ...any) {
+func NoError(tb testing.TB, err error, msgAndArgs ...any) {
+	tb.Helper()
 	if err == nil {
 		return
 	}
-	t.Helper()
 	msg := formatMsgAndArgs("Unexpected error:", msgAndArgs...)
-	t.Fatalf("%s\n%+v", msg, err)
+	tb.Fatalf("%s\n%+v", msg, err)
 }
 
 // Panics asserts that the given function panics.
-func Panics(t testing.TB, fn func(), msgAndArgs ...any) {
-	t.Helper()
+func Panics(tb testing.TB, fn func(), msgAndArgs ...any) {
+	tb.Helper()
 	defer func() {
 		if recover() == nil {
 			msg := formatMsgAndArgs("Expected function to panic", msgAndArgs...)
-			t.Fatal(msg)
+			tb.Fatal(msg)
 		}
 	}()
 	fn()
 }
 
 // Zero asserts that a value is its zero value.
-func Zero[T any](t testing.TB, value T, msgAndArgs ...any) {
+func Zero[T any](tb testing.TB, value T, msgAndArgs ...any) {
+	tb.Helper()
 	var zero T
 	if objectsAreEqual(value, zero) {
 		return
@@ -77,22 +79,26 @@ func Zero[T any](t testing.TB, value T, msgAndArgs ...any) {
 	if (val.Kind() == reflect.Slice || val.Kind() == reflect.Map || val.Kind() == reflect.Array) && val.Len() == 0 {
 		return
 	}
-	t.Helper()
 	msg := formatMsgAndArgs("Expected zero value but got:", msgAndArgs...)
-	t.Fatalf("%s\n%v", msg, value)
+	tb.Fatalf("%s\n%v", msg, value)
 }
 
-func NotZero[T any](t testing.TB, value T, msgAndArgs ...any) {
+func NotZero[T any](tb testing.TB, value T, msgAndArgs ...any) {
+	tb.Helper()
 	var zero T
 	if !objectsAreEqual(value, zero) {
 		val := reflect.ValueOf(value)
-		if !((val.Kind() == reflect.Slice || val.Kind() == reflect.Map || val.Kind() == reflect.Array) && val.Len() == 0) {
+		switch val.Kind() {
+		case reflect.Slice, reflect.Map, reflect.Array:
+			if val.Len() > 0 {
+				return
+			}
+		default:
 			return
 		}
 	}
-	t.Helper()
 	msg := formatMsgAndArgs("Unexpected zero value:", msgAndArgs...)
-	t.Fatalf("%s\n%v", msg, value)
+	tb.Fatalf("%s\n%v", msg, value)
 }
 
 func formatMsgAndArgs(msg string, args ...any) string {

internal/assert/assertions_test.go

@@ -1,6 +1,7 @@
 package assert
 
 import (
+	"errors"
 	"fmt"
 	"testing"
 )
@@ -12,135 +13,167 @@ type Data struct {
 
 func TestBadMessage(t *testing.T) {
 	invalidMessage := func() { True(t, false, 1234) }
-	assertOk(t, "Non-fmt message value", func(t testing.TB) {
-		Panics(t, invalidMessage)
+	assertOk(t, "Non-fmt message value", func(tb testing.TB) {
+		tb.Helper()
+		Panics(tb, invalidMessage)
 	})
-	assertFail(t, "Non-fmt message value", func(t testing.TB) {
-		True(t, false, "example %s", "message")
+	assertFail(t, "Non-fmt message value", func(tb testing.TB) {
+		tb.Helper()
+		True(tb, false, "example %s", "message")
 	})
 }
 
 func TestTrue(t *testing.T) {
-	assertOk(t, "Succeed", func(t testing.TB) {
-		True(t, 1 > 0)
+	assertOk(t, "Succeed", func(tb testing.TB) {
+		tb.Helper()
+		True(tb, 1 > 0)
 	})
-	assertFail(t, "Fail", func(t testing.TB) {
-		True(t, 1 < 0)
+	assertFail(t, "Fail", func(tb testing.TB) {
+		tb.Helper()
+		True(tb, 1 < 0)
 	})
 }
 
 func TestFalse(t *testing.T) {
-	assertOk(t, "Succeed", func(t testing.TB) {
-		False(t, 1 < 0)
+	assertOk(t, "Succeed", func(tb testing.TB) {
+		tb.Helper()
+		False(tb, 1 < 0)
 	})
-	assertFail(t, "Fail", func(t testing.TB) {
-		False(t, 1 > 0)
+	assertFail(t, "Fail", func(tb testing.TB) {
+		tb.Helper()
+		False(tb, 1 > 0)
 	})
 }
 
 func TestEqual(t *testing.T) {
-	assertOk(t, "Nil", func(t testing.TB) {
-		Equal(t, interface{}(nil), interface{}(nil))
+	assertOk(t, "Nil", func(tb testing.TB) {
+		tb.Helper()
+		Equal(tb, interface{}(nil), interface{}(nil))
 	})
-	assertOk(t, "Identical structs", func(t testing.TB) {
-		Equal(t, Data{"expected", 1234}, Data{"expected", 1234})
+	assertOk(t, "Identical structs", func(tb testing.TB) {
+		tb.Helper()
+		Equal(tb, Data{"expected", 1234}, Data{"expected", 1234})
 	})
-	assertFail(t, "Different structs", func(t testing.TB) {
-		Equal(t, Data{"expected", 1234}, Data{"actual", 1234})
+	assertFail(t, "Different structs", func(tb testing.TB) {
+		tb.Helper()
+		Equal(tb, Data{"expected", 1234}, Data{"actual", 1234})
 	})
-	assertOk(t, "Identical numbers", func(t testing.TB) {
-		Equal(t, 1234, 1234)
+	assertOk(t, "Identical numbers", func(tb testing.TB) {
+		tb.Helper()
+		Equal(tb, 1234, 1234)
 	})
-	assertFail(t, "Identical numbers", func(t testing.TB) {
-		Equal(t, 1234, 1324)
+	assertFail(t, "Identical numbers", func(tb testing.TB) {
+		tb.Helper()
+		Equal(tb, 1234, 1324)
 	})
-	assertOk(t, "Zero-length byte arrays", func(t testing.TB) {
-		Equal(t, []byte(nil), []byte(""))
+	assertOk(t, "Zero-length byte arrays", func(tb testing.TB) {
+		tb.Helper()
+		Equal(tb, []byte(nil), []byte(""))
 	})
-	assertOk(t, "Identical byte arrays", func(t testing.TB) {
-		Equal(t, []byte{1, 2, 3, 4}, []byte{1, 2, 3, 4})
+	assertOk(t, "Identical byte arrays", func(tb testing.TB) {
+		tb.Helper()
+		Equal(tb, []byte{1, 2, 3, 4}, []byte{1, 2, 3, 4})
 	})
-	assertFail(t, "Different byte arrays", func(t testing.TB) {
-		Equal(t, []byte{1, 2, 3, 4}, []byte{1, 3, 2, 4})
+	assertFail(t, "Different byte arrays", func(tb testing.TB) {
+		tb.Helper()
+		Equal(tb, []byte{1, 2, 3, 4}, []byte{1, 3, 2, 4})
 	})
-	assertOk(t, "Identical strings", func(t testing.TB) {
-		Equal(t, "example", "example")
+	assertOk(t, "Identical strings", func(tb testing.TB) {
+		tb.Helper()
+		Equal(tb, "example", "example")
 	})
-	assertFail(t, "Identical strings", func(t testing.TB) {
-		Equal(t, "example", "elpmaxe")
+	assertFail(t, "Identical strings", func(tb testing.TB) {
+		tb.Helper()
+		Equal(tb, "example", "elpmaxe")
 	})
 }
 
 func TestError(t *testing.T) {
-	assertOk(t, "Error", func(t testing.TB) {
-		Error(t, fmt.Errorf("example"))
+	assertOk(t, "Error", func(tb testing.TB) {
+		tb.Helper()
+		Error(tb, errors.New("example"))
 	})
-	assertFail(t, "Nil", func(t testing.TB) {
-		Error(t, nil)
+	assertFail(t, "Nil", func(tb testing.TB) {
+		tb.Helper()
+		Error(tb, nil)
 	})
 }
 
 func TestNoError(t *testing.T) {
-	assertFail(t, "Error", func(t testing.TB) {
-		NoError(t, fmt.Errorf("example"))
+	assertFail(t, "Error", func(tb testing.TB) {
+		tb.Helper()
+		NoError(tb, errors.New("example"))
 	})
-	assertOk(t, "Nil", func(t testing.TB) {
-		NoError(t, nil)
+	assertOk(t, "Nil", func(tb testing.TB) {
+		tb.Helper()
+		NoError(tb, nil)
 	})
 }
 
 func TestPanics(t *testing.T) {
 	willPanic := func() { panic("example") }
 	wontPanic := func() {}
-	assertOk(t, "Will panic", func(t testing.TB) {
-		Panics(t, willPanic)
+	assertOk(t, "Will panic", func(tb testing.TB) {
+		tb.Helper()
+		Panics(tb, willPanic)
 	})
-	assertFail(t, "Won't panic", func(t testing.TB) {
-		Panics(t, wontPanic)
+	assertFail(t, "Won't panic", func(tb testing.TB) {
+		tb.Helper()
+		Panics(tb, wontPanic)
 	})
 }
 
 func TestZero(t *testing.T) {
-	assertOk(t, "Empty struct", func(t testing.TB) {
-		Zero(t, Data{})
+	assertOk(t, "Empty struct", func(tb testing.TB) {
+		tb.Helper()
+		Zero(tb, Data{})
 	})
-	assertFail(t, "Non-empty struct", func(t testing.TB) {
-		Zero(t, Data{Label: "example"})
+	assertFail(t, "Non-empty struct", func(tb testing.TB) {
+		tb.Helper()
+		Zero(tb, Data{Label: "example"})
 	})
-	assertOk(t, "Nil slice", func(t testing.TB) {
+	assertOk(t, "Nil slice", func(tb testing.TB) {
+		tb.Helper()
 		var slice []int
-		Zero(t, slice)
+		Zero(tb, slice)
 	})
-	assertFail(t, "Non-empty slice", func(t testing.TB) {
+	assertFail(t, "Non-empty slice", func(tb testing.TB) {
+		tb.Helper()
 		slice := []int{1, 2, 3, 4}
-		Zero(t, slice)
+		Zero(tb, slice)
 	})
-	assertOk(t, "Zero-length slice", func(t testing.TB) {
+	assertOk(t, "Zero-length slice", func(tb testing.TB) {
+		tb.Helper()
 		slice := []int{}
-		Zero(t, slice)
+		Zero(tb, slice)
 	})
 }
 
 func TestNotZero(t *testing.T) {
-	assertFail(t, "Empty struct", func(t testing.TB) {
+	assertFail(t, "Empty struct", func(tb testing.TB) {
+		tb.Helper()
 		zero := Data{}
-		NotZero(t, zero)
+		NotZero(tb, zero)
 	})
-	assertOk(t, "Non-empty struct", func(t testing.TB) {
+	assertOk(t, "Non-empty struct", func(tb testing.TB) {
+		tb.Helper()
 		notZero := Data{Label: "example"}
-		NotZero(t, notZero)
+		NotZero(tb, notZero)
 	})
-	assertFail(t, "Nil slice", func(t testing.TB) {
+	assertFail(t, "Nil slice", func(tb testing.TB) {
+		tb.Helper()
 		var slice []int
-		NotZero(t, slice)
+		NotZero(tb, slice)
 	})
-	assertFail(t, "Zero-length slice", func(t testing.TB) {
+	assertFail(t, "Zero-length slice", func(tb testing.TB) {
+		tb.Helper()
 		slice := []int{}
-		NotZero(t, slice)
+		NotZero(tb, slice)
 	})
-	assertOk(t, "Non-empty slice", func(t testing.TB) {
+	assertOk(t, "Non-empty slice", func(tb testing.TB) {
+		tb.Helper()
 		slice := []int{1, 2, 3, 4}
-		NotZero(t, slice)
+		NotZero(tb, slice)
 	})
 }
 
@@ -157,7 +190,7 @@ func (t *testCase) Fatalf(message string, args ...interface{}) {
 	t.failed = fmt.Sprintf(message, args...)
 }
 
-func assertFail(t *testing.T, name string, fn func(t testing.TB)) {
+func assertFail(t *testing.T, name string, fn func(testing.TB)) {
 	t.Helper()
 	t.Run(name, func(t *testing.T) {
 		t.Helper()
@@ -171,7 +204,7 @@ func assertFail(t *testing.T, name string, fn func(t testing.TB)) {
 	})
 }
 
-func assertOk(t *testing.T, name string, fn func(t testing.TB)) {
+func assertOk(t *testing.T, name string, fn func(testing.TB)) {
 	t.Helper()
 	t.Run(name, func(t *testing.T) {
 		t.Helper()

internal/characters/ascii.go

@@ -1,6 +1,6 @@
 package characters
 
-var invalidAsciiTable = [256]bool{
+var invalidASCIITable = [256]bool{
 	0x00: true,
 	0x01: true,
 	0x02: true,
@@ -37,6 +37,6 @@ var invalidAsciiTable = [256]bool{
 	0x7F: true,
 }
 
-func InvalidAscii(b byte) bool {
-	return invalidAsciiTable[b]
+func InvalidASCII(b byte) bool {
+	return invalidASCIITable[b]
 }

internal/characters/utf8.go

@@ -1,20 +1,12 @@
+// Package characters provides functions for working with string encodings.
 package characters
 
 import (
 	"unicode/utf8"
 )
 
-type utf8Err struct {
-	Index int
-	Size  int
-}
-
-func (u utf8Err) Zero() bool {
-	return u.Size == 0
-}
-
-// Verified that a given string is only made of valid UTF-8 characters allowed
-// by the TOML spec:
+// Utf8TomlValidAlreadyEscaped verifies that a given string is only made of
+// valid UTF-8 characters allowed by the TOML spec:
 //
 // Any Unicode character may be used except those that must be escaped:
 // quotation mark, backslash, and the control characters other than tab (U+0000
@@ -23,8 +15,8 @@ func (u utf8Err) Zero() bool {
 // It is a copy of the Go 1.17 utf8.Valid implementation, tweaked to exit early
 // when a character is not allowed.
 //
-// The returned utf8Err is Zero() if the string is valid, or contains the byte
-// index and size of the invalid character.
+// The returned slice is empty if the string is valid, or contains the bytes
+// of the invalid character.
 //
 // quotation mark => already checked
 // backslash => already checked
@@ -32,9 +24,8 @@ func (u utf8Err) Zero() bool {
 // 0x9 => tab, ok
 // 0xA - 0x1F => invalid
 // 0x7F => invalid
-func Utf8TomlValidAlreadyEscaped(p []byte) (err utf8Err) {
+func Utf8TomlValidAlreadyEscaped(p []byte) []byte {
 	// Fast path. Check for and skip 8 bytes of ASCII characters per iteration.
-	offset := 0
 	for len(p) >= 8 {
 		// Combining two 32 bit loads allows the same code to be used
 		// for 32 and 64 bit platforms.
@@ -48,24 +39,19 @@ func Utf8TomlValidAlreadyEscaped(p []byte) (err utf8Err) {
 		}
 
 		for i, b := range p[:8] {
-			if InvalidAscii(b) {
-				err.Index = offset + i
-				err.Size = 1
-				return
+			if InvalidASCII(b) {
+				return p[i : i+1]
 			}
 		}
 
 		p = p[8:]
-		offset += 8
 	}
 	n := len(p)
 	for i := 0; i < n; {
 		pi := p[i]
 		if pi < utf8.RuneSelf {
-			if InvalidAscii(pi) {
-				err.Index = offset + i
-				err.Size = 1
-				return
+			if InvalidASCII(pi) {
+				return p[i : i+1]
 			}
 			i++
 			continue
@@ -73,44 +59,34 @@ func Utf8TomlValidAlreadyEscaped(p []byte) (err utf8Err) {
 		x := first[pi]
 		if x == xx {
 			// Illegal starter byte.
-			err.Index = offset + i
-			err.Size = 1
-			return
+			return p[i : i+1]
 		}
 		size := int(x & 7)
 		if i+size > n {
 			// Short or invalid.
-			err.Index = offset + i
-			err.Size = n - i
-			return
+			return p[i:n]
 		}
 		accept := acceptRanges[x>>4]
 		if c := p[i+1]; c < accept.lo || accept.hi < c {
-			err.Index = offset + i
-			err.Size = 2
-			return
-		} else if size == 2 {
+			return p[i : i+2]
+		} else if size == 2 { //revive:disable:empty-block
 		} else if c := p[i+2]; c < locb || hicb < c {
-			err.Index = offset + i
-			err.Size = 3
-			return
-		} else if size == 3 {
+			return p[i : i+3]
+		} else if size == 3 { //revive:disable:empty-block
 		} else if c := p[i+3]; c < locb || hicb < c {
-			err.Index = offset + i
-			err.Size = 4
-			return
+			return p[i : i+4]
 		}
 		i += size
 	}
-	return
+	return nil
 }
 
-// Return the size of the next rune if valid, 0 otherwise.
+// Utf8ValidNext returns the size of the next rune if valid, 0 otherwise.
 func Utf8ValidNext(p []byte) int {
 	c := p[0]
 
 	if c < utf8.RuneSelf {
-		if InvalidAscii(c) {
+		if InvalidASCII(c) {
 			return 0
 		}
 		return 1
@@ -129,10 +105,10 @@ func Utf8ValidNext(p []byte) int {
 	accept := acceptRanges[x>>4]
 	if c := p[1]; c < accept.lo || accept.hi < c {
 		return 0
-	} else if size == 2 {
+	} else if size == 2 { //nolint:revive
 	} else if c := p[2]; c < locb || hicb < c {
 		return 0
-	} else if size == 3 {
+	} else if size == 3 { //nolint:revive
 	} else if c := p[3]; c < locb || hicb < c {
 		return 0
 	}

internal/cli/cli.go

@@ -1,3 +1,4 @@
+// Package cli provides common functions for command-line programs.
 package cli
 
 import (
@@ -27,17 +28,16 @@ func (p *Program) Execute() {
 	os.Exit(p.main(flag.Args(), os.Stdin, os.Stdout, os.Stderr))
 }
 
-func (p *Program) main(files []string, input io.Reader, output, error io.Writer) int {
+func (p *Program) main(files []string, input io.Reader, output, stderr io.Writer) int {
 	err := p.run(files, input, output)
 	if err != nil {
-
 		var derr *toml.DecodeError
 		if errors.As(err, &derr) {
-			fmt.Fprintln(error, derr.String())
+			_, _ = fmt.Fprintln(stderr, derr.String())
 			row, col := derr.Position()
-			fmt.Fprintln(error, "error occurred at row", row, "column", col)
+			_, _ = fmt.Fprintln(stderr, "error occurred at row", row, "column", col)
 		} else {
-			fmt.Fprintln(error, err.Error())
+			_, _ = fmt.Fprintln(stderr, err.Error())
 		}
 
 		return -1
@@ -54,7 +54,7 @@ func (p *Program) run(files []string, input io.Reader, output io.Writer) error {
 		if err != nil {
 			return err
 		}
-		defer f.Close()
+		defer func() { _ = f.Close() }()
 		input = f
 	}
 	return p.Fn(input, output)
@@ -71,7 +71,7 @@ func (p *Program) runAllFilesInPlace(files []string) error {
 }
 
 func (p *Program) runFileInPlace(path string) error {
-	in, err := os.ReadFile(path)
+	in, err := os.ReadFile(path) // #nosec G304
 	if err != nil {
 		return err
 	}
@@ -83,5 +83,5 @@ func (p *Program) runFileInPlace(path string) error {
 		return err
 	}
 
-	return os.WriteFile(path, out.Bytes(), 0600)
+	return os.WriteFile(path, out.Bytes(), 0o600)
 }

internal/cli/cli_test.go

@@ -2,7 +2,7 @@ package cli
 
 import (
 	"bytes"
-	"fmt"
+	"errors"
 	"io"
 	"os"
 	"path"
@@ -23,7 +23,7 @@ func TestProcessMainStdin(t *testing.T) {
 	stderr := new(bytes.Buffer)
 	input := strings.NewReader("this is the input")
 
-	exit := processMain([]string{}, input, stdout, stderr, func(r io.Reader, w io.Writer) error {
+	exit := processMain([]string{}, input, stdout, stderr, func(io.Reader, io.Writer) error {
 		return nil
 	})
 
@@ -37,8 +37,8 @@ func TestProcessMainStdinErr(t *testing.T) {
 	stderr := new(bytes.Buffer)
 	input := strings.NewReader("this is the input")
 
-	exit := processMain([]string{}, input, stdout, stderr, func(r io.Reader, w io.Writer) error {
-		return fmt.Errorf("something bad")
+	exit := processMain([]string{}, input, stdout, stderr, func(io.Reader, io.Writer) error {
+		return errors.New("something bad")
 	})
 
 	assert.Equal(t, -1, exit)
@@ -51,7 +51,7 @@ func TestProcessMainStdinDecodeErr(t *testing.T) {
 	stderr := new(bytes.Buffer)
 	input := strings.NewReader("this is the input")
 
-	exit := processMain([]string{}, input, stdout, stderr, func(r io.Reader, w io.Writer) error {
+	exit := processMain([]string{}, input, stdout, stderr, func(io.Reader, io.Writer) error {
 		var v interface{}
 		return toml.Unmarshal([]byte(`qwe = 001`), &v)
 	})
@@ -62,16 +62,16 @@ func TestProcessMainStdinDecodeErr(t *testing.T) {
 }
 
 func TestProcessMainFileExists(t *testing.T) {
-	tmpfile, err := os.CreateTemp("", "example")
+	tmpfile, err := os.CreateTemp(t.TempDir(), "example")
 	assert.NoError(t, err)
-	defer os.Remove(tmpfile.Name())
-	_, err = tmpfile.Write([]byte(`some data`))
+	_, err = tmpfile.WriteString(`some data`)
 	assert.NoError(t, err)
+	assert.NoError(t, tmpfile.Close())
 
 	stdout := new(bytes.Buffer)
 	stderr := new(bytes.Buffer)
 
-	exit := processMain([]string{tmpfile.Name()}, nil, stdout, stderr, func(r io.Reader, w io.Writer) error {
+	exit := processMain([]string{tmpfile.Name()}, nil, stdout, stderr, func(io.Reader, io.Writer) error {
 		return nil
 	})
 
@@ -84,7 +84,7 @@ func TestProcessMainFileDoesNotExist(t *testing.T) {
 	stdout := new(bytes.Buffer)
 	stderr := new(bytes.Buffer)
 
-	exit := processMain([]string{"/lets/hope/this/does/not/exist"}, nil, stdout, stderr, func(r io.Reader, w io.Writer) error {
+	exit := processMain([]string{"/lets/hope/this/does/not/exist"}, nil, stdout, stderr, func(io.Reader, io.Writer) error {
 		return nil
 	})
 
@@ -94,16 +94,14 @@ func TestProcessMainFileDoesNotExist(t *testing.T) {
 }
 
 func TestProcessMainFilesInPlace(t *testing.T) {
-	dir, err := os.MkdirTemp("", "")
-	assert.NoError(t, err)
-	defer os.RemoveAll(dir)
+	dir := t.TempDir()
 
 	path1 := path.Join(dir, "file1")
 	path2 := path.Join(dir, "file2")
 
-	err = os.WriteFile(path1, []byte("content 1"), 0600)
+	err := os.WriteFile(path1, []byte("content 1"), 0o600)
 	assert.NoError(t, err)
-	err = os.WriteFile(path2, []byte("content 2"), 0600)
+	err = os.WriteFile(path2, []byte("content 2"), 0o600)
 	assert.NoError(t, err)
 
 	p := Program{
@@ -136,17 +134,15 @@ func TestProcessMainFilesInPlaceErrRead(t *testing.T) {
 }
 
 func TestProcessMainFilesInPlaceFailFn(t *testing.T) {
-	dir, err := os.MkdirTemp("", "")
-	assert.NoError(t, err)
-	defer os.RemoveAll(dir)
+	dir := t.TempDir()
 
 	path1 := path.Join(dir, "file1")
 
-	err = os.WriteFile(path1, []byte("content 1"), 0600)
+	err := os.WriteFile(path1, []byte("content 1"), 0o600)
 	assert.NoError(t, err)
 
 	p := Program{
-		Fn:      func(io.Reader, io.Writer) error { return fmt.Errorf("oh no") },
+		Fn:      func(io.Reader, io.Writer) error { return errors.New("oh no") },
 		Inplace: true,
 	}
 

internal/danger/danger.go

@@ -1,21 +1,21 @@
+// Package danger provides optimized unsafe functions.
 package danger
 
 import (
 	"fmt"
-	"reflect"
 	"unsafe"
 )
 
 const maxInt = uintptr(int(^uint(0) >> 1))
 
 func SubsliceOffset(data []byte, subslice []byte) int {
-	datap := (*reflect.SliceHeader)(unsafe.Pointer(&data))
-	hlp := (*reflect.SliceHeader)(unsafe.Pointer(&subslice))
+	datap := uintptr(unsafe.Pointer(unsafe.SliceData(data)))   // #nosec G103
+	hlp := uintptr(unsafe.Pointer(unsafe.SliceData(subslice))) // #nosec G103
 
-	if hlp.Data < datap.Data {
-		panic(fmt.Errorf("subslice address (%d) is before data address (%d)", hlp.Data, datap.Data))
+	if hlp < datap {
+		panic(fmt.Errorf("subslice address (%d) is before data address (%d)", hlp, datap))
 	}
-	offset := hlp.Data - datap.Data
+	offset := hlp - datap
 
 	if offset > maxInt {
 		panic(fmt.Errorf("slice offset larger than int (%d)", offset))
@@ -23,12 +23,12 @@ func SubsliceOffset(data []byte, subslice []byte) int {
 
 	intoffset := int(offset)
 
-	if intoffset > datap.Len {
-		panic(fmt.Errorf("slice offset (%d) is farther than data length (%d)", intoffset, datap.Len))
+	if intoffset > len(data) {
+		panic(fmt.Errorf("slice offset (%d) is farther than data length (%d)", intoffset, len(data)))
 	}
 
-	if intoffset+hlp.Len > datap.Len {
-		panic(fmt.Errorf("slice ends (%d+%d) is farther than data length (%d)", intoffset, hlp.Len, datap.Len))
+	if intoffset+len(subslice) > len(data) {
+		panic(fmt.Errorf("slice ends (%d+%d) is farther than data length (%d)", intoffset, len(subslice), len(data)))
 	}
 
 	return intoffset
@@ -38,28 +38,27 @@ func BytesRange(start []byte, end []byte) []byte {
 	if start == nil || end == nil {
 		panic("cannot call BytesRange with nil")
 	}
-	startp := (*reflect.SliceHeader)(unsafe.Pointer(&start))
-	endp := (*reflect.SliceHeader)(unsafe.Pointer(&end))
 
-	if startp.Data > endp.Data {
-		panic(fmt.Errorf("start pointer address (%d) is after end pointer address (%d)", startp.Data, endp.Data))
+	startp := uintptr(unsafe.Pointer(unsafe.SliceData(start))) // #nosec G103
+	endp := uintptr(unsafe.Pointer(unsafe.SliceData(end)))     // #nosec G103
+
+	if startp > endp {
+		panic(fmt.Errorf("start pointer address (%d) is after end pointer address (%d)", startp, endp))
 	}
 
-	l := startp.Len
-	endLen := int(endp.Data-startp.Data) + endp.Len
+	l := len(start)
+	endLen := int(endp-startp) + len(end)
 	if endLen > l {
 		l = endLen
 	}
 
-	if l > startp.Cap {
-		panic(fmt.Errorf("range length is larger than capacity"))
+	if l > cap(start) {
+		panic("range length is larger than capacity")
 	}
 
 	return start[:l]
 }
 
 func Stride(ptr unsafe.Pointer, size uintptr, offset int) unsafe.Pointer {
-	// TODO: replace with unsafe.Add when Go 1.17 is released
-	//   https://github.com/golang/go/issues/40481
-	return unsafe.Pointer(uintptr(ptr) + uintptr(int(size)*offset))
+	return unsafe.Add(ptr, size*uintptr(offset))
 }

internal/danger/typeid.go

@@ -5,7 +5,7 @@ import (
 	"unsafe"
 )
 
-// typeID is used as key in encoder and decoder caches to enable using
+// TypeID is used as key in encoder and decoder caches to enable using
 // the optimize runtime.mapaccess2_fast64 function instead of the more
 // expensive lookup if we were to use reflect.Type as map key.
 //
@@ -19,5 +19,5 @@ func MakeTypeID(t reflect.Type) TypeID {
 	// reflect.Type has the fields:
 	// typ unsafe.Pointer
 	// ptr unsafe.Pointer
-	return TypeID((*[2]unsafe.Pointer)(unsafe.Pointer(&t))[1])
+	return TypeID((*[2]unsafe.Pointer)(unsafe.Pointer(&t))[1]) // #nosec G103
 }

internal/imported_tests/marshal_imported_test.go

@@ -1,4 +1,4 @@
-package imported_tests
+package imported_tests //revive:disable:var-naming
 
 // Those tests have been imported from v1, but adjust to match the new
 // defaults of v2.
@@ -21,12 +21,12 @@ func TestDocMarshal(t *testing.T) {
 		Subdocs     testDocSubs       `toml:"subdoc"`
 		Basics      testDocBasics     `toml:"basic"`
 		SubDocList  []testSubDoc      `toml:"subdoclist"`
-		err         int               `toml:"shouldntBeHere"`
+		err         int               `toml:"shouldntBeHere"` //nolint:unused
 		unexported  int               `toml:"shouldntBeHere"`
 		Unexported2 int               `toml:"-"`
 	}
 
-	var docData = testDoc{
+	docData := testDoc{
 		Title:       "TOML Marshal Testing",
 		unexported:  0,
 		Unexported2: 0,
@@ -128,8 +128,7 @@ String2 = 'Two'
 String2 = 'Three'
 `
 
-	assert.Equal(t, string(expected), string(result))
-
+	assert.Equal(t, expected, string(result))
 }
 
 func TestEmptyMarshal(t *testing.T) {
@@ -164,7 +163,7 @@ stringlist = []
 [map]
 `
 
-	assert.Equal(t, string(expected), string(result))
+	assert.Equal(t, expected, string(result))
 }
 
 type textMarshaler struct {

internal/imported_tests/unmarshal_imported_test.go

@@ -1,4 +1,4 @@
-package imported_tests
+package imported_tests //revive:disable:var-naming
 
 // Those tests were imported directly from go-toml v1
 // https://raw.githubusercontent.com/pelletier/go-toml/a2e52561804c6cd9392ebf0048ca64fe4af67a43/marshal_test.go
@@ -149,9 +149,6 @@ type quotedKeyMarshalTestStruct struct {
 	SubList []basicMarshalTestSubStruct `toml:"W.sublist-𝟘"`
 }
 
-// TODO: Remove nolint once var is used by a test
-//
-//nolint:deadcode,unused,varcheck
 var quotedKeyMarshalTestData = quotedKeyMarshalTestStruct{
 	String:  "Hello",
 	Float:   3.5,
@@ -161,7 +158,7 @@ var quotedKeyMarshalTestData = quotedKeyMarshalTestStruct{
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused,varcheck
+//nolint:unused
 var quotedKeyMarshalTestToml = []byte(`"Yfloat-𝟘" = 3.5
 "Z.string-àéù" = "Hello"
 
@@ -183,11 +180,12 @@ type testDoc struct {
 	Subdocs     testDocSubs       `toml:"subdoc"`
 	Basics      testDocBasics     `toml:"basic"`
 	SubDocList  []testSubDoc      `toml:"subdoclist"`
-	err         int               `toml:"shouldntBeHere"` // nolint:structcheck,unused
+	err         int               `toml:"shouldntBeHere"` //nolint:unused
 	unexported  int               `toml:"shouldntBeHere"`
 	Unexported2 int               `toml:"-"`
 }
 
+//nolint:unused
 type testMapDoc struct {
 	Title    string            `toml:"title"`
 	BasicMap map[string]string `toml:"basic_map"`
@@ -274,7 +272,7 @@ var docData = testDoc{
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused,varcheck
+//nolint:unused
 var mapTestDoc = testMapDoc{
 	Title: "TOML Marshal Testing",
 	BasicMap: map[string]string{
@@ -543,31 +541,35 @@ func TestNestedUnmarshal(t *testing.T) {
 	assert.Equal(t, nestedTestData, result)
 }
 
+//nolint:unused
 type customMarshalerParent struct {
 	Self    customMarshaler   `toml:"me"`
 	Friends []customMarshaler `toml:"friends"`
 }
 
+//nolint:unused
 type customMarshaler struct {
 	FirstName string
 	LastName  string
 }
 
+//nolint:unused
 func (c customMarshaler) MarshalTOML() ([]byte, error) {
 	fullName := fmt.Sprintf("%s %s", c.FirstName, c.LastName)
 	return []byte(fullName), nil
 }
 
+//nolint:unused
 var customMarshalerData = customMarshaler{FirstName: "Sally", LastName: "Fields"}
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused,varcheck
+//nolint:unused
 var customMarshalerToml = []byte(`Sally Fields`)
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused,varcheck
+//nolint:unused
 var nestedCustomMarshalerData = customMarshalerParent{
 	Self:    customMarshaler{FirstName: "Maiku", LastName: "Suteda"},
 	Friends: []customMarshaler{customMarshalerData},
@@ -575,7 +577,7 @@ var nestedCustomMarshalerData = customMarshalerParent{
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused,varcheck
+//nolint:unused
 var nestedCustomMarshalerToml = []byte(`friends = ["Sally Fields"]
 me = "Maiku Suteda"
 `)
@@ -590,7 +592,7 @@ func (x *IntOrString) MarshalTOML() ([]byte, error) {
 	s := *(*string)(x)
 	_, err := strconv.Atoi(s)
 	if err != nil {
-		return []byte(fmt.Sprintf(`"%s"`, s)), nil
+		return []byte(fmt.Sprintf(`"%s"`, s)), nil //nolint:nilerr
 	}
 	return []byte(s), nil
 }
@@ -662,7 +664,7 @@ func (m *textPointerMarshaler) MarshalText() ([]byte, error) {
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused,varcheck
+//nolint:unused
 var commentTestToml = []byte(`
 # it's a comment on type
 [postgres]
@@ -687,6 +689,7 @@ var commentTestToml = []byte(`
     My = "Baar"
 `)
 
+//nolint:unused
 type mapsTestStruct struct {
 	Simple map[string]string
 	Paths  map[string]string
@@ -700,7 +703,7 @@ type mapsTestStruct struct {
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused,varcheck
+//nolint:unused
 var mapsTestData = mapsTestStruct{
 	Simple: map[string]string{
 		"one plus one": "two",
@@ -724,7 +727,7 @@ var mapsTestData = mapsTestStruct{
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused,varcheck
+//nolint:unused
 var mapsTestToml = []byte(`
 [Other]
   "testing" = 3.9999
@@ -747,7 +750,7 @@ var mapsTestToml = []byte(`
 
 // TODO: Remove nolint once type is used by a test
 //
-//nolint:deadcode,unused
+//nolint:unused
 type structArrayNoTag struct {
 	A struct {
 		B []int64
@@ -757,7 +760,7 @@ type structArrayNoTag struct {
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused,varcheck
+//nolint:unused
 var customTagTestToml = []byte(`
 [postgres]
   password = "bvalue"
@@ -772,7 +775,7 @@ var customTagTestToml = []byte(`
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused,varcheck
+//nolint:unused
 var customCommentTagTestToml = []byte(`
 # db connection
 [postgres]
@@ -786,7 +789,7 @@ var customCommentTagTestToml = []byte(`
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused,varcheck
+//nolint:unused
 var customCommentedTagTestToml = []byte(`
 [postgres]
   # password = "bvalue"
@@ -841,7 +844,7 @@ func TestUnmarshalTabInStringAndQuotedKey(t *testing.T) {
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused,varcheck
+//nolint:unused
 var customMultilineTagTestToml = []byte(`int_slice = [
   1,
   2,
@@ -851,7 +854,7 @@ var customMultilineTagTestToml = []byte(`int_slice = [
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused,varcheck
+//nolint:unused
 var testDocBasicToml = []byte(`
 [document]
   bool_val = true
@@ -862,16 +865,12 @@ var testDocBasicToml = []byte(`
   uint_val = 5001
 `)
 
-// TODO: Remove nolint once type is used by a test
-//
-//nolint:deadcode
+//nolint:unused
 type testDocCustomTag struct {
 	Doc testDocBasicsCustomTag `file:"document"`
 }
 
-// TODO: Remove nolint once type is used by a test
-//
-//nolint:deadcode
+//nolint:unused
 type testDocBasicsCustomTag struct {
 	Bool       bool      `file:"bool_val"`
 	Date       time.Time `file:"date_val"`
@@ -882,9 +881,7 @@ type testDocBasicsCustomTag struct {
 	unexported int       `file:"shouldntBeHere"`
 }
 
-// TODO: Remove nolint once var is used by a test
-//
-//nolint:deadcode,varcheck
+//nolint:unused
 var testDocCustomTagData = testDocCustomTag{
 	Doc: testDocBasicsCustomTag{
 		Bool:       true,
@@ -987,13 +984,13 @@ func TestUnmarshalInvalidPointerKind(t *testing.T) {
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused
+//nolint:unused
 type testDuration struct {
 	Nanosec   time.Duration  `toml:"nanosec"`
 	Microsec1 time.Duration  `toml:"microsec1"`
 	Microsec2 *time.Duration `toml:"microsec2"`
 	Millisec  time.Duration  `toml:"millisec"`
-	Sec       time.Duration  `toml:"sec"`
+	Sec       time.Duration  `toml:"sec"` //nolint:staticcheck
 	Min       time.Duration  `toml:"min"`
 	Hour      time.Duration  `toml:"hour"`
 	Mixed     time.Duration  `toml:"mixed"`
@@ -1002,7 +999,7 @@ type testDuration struct {
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused,varcheck
+//nolint:unused
 var testDurationToml = []byte(`
 nanosec = "1ns"
 microsec1 = "1us"
@@ -1017,7 +1014,7 @@ a_string = "15s"
 
 // TODO: Remove nolint once var is used by a test
 //
-//nolint:deadcode,unused,varcheck
+//nolint:unused
 var testDurationToml2 = []byte(`a_string = "15s"
 hour = "1h0m0s"
 microsec1 = "1µs"
@@ -1031,15 +1028,14 @@ sec = "1s"
 
 // TODO: Remove nolint once type is used by a test
 //
-//nolint:deadcode,unused
+//nolint:unused
 type testBadDuration struct {
 	Val time.Duration `toml:"val"`
 }
 
 // TODO: add back camelCase test
-var testCamelCaseKeyToml = []byte(`fooBar = 10`) //nolint:unused
+var testCamelCaseKeyToml = []byte(`fooBar = 10`)
 
-//nolint:unused
 func TestUnmarshalCamelCaseKey(t *testing.T) {
 	t.Skipf("don't know if it is a good idea to automatically convert like that yet")
 	var x struct {
@@ -1058,7 +1054,7 @@ func TestUnmarshalCamelCaseKey(t *testing.T) {
 
 func TestUnmarshalNegativeUint(t *testing.T) {
 	t.Skipf("not sure if we this should always error")
-	type check struct{ U uint } // nolint:unused
+	type check struct{ U uint }
 	err := toml.Unmarshal([]byte("U = -1"), &check{})
 	assert.Error(t, err)
 }
@@ -1535,7 +1531,7 @@ func TestUnmarshalLocalDateTime(t *testing.T) {
 	}
 
 	for i, example := range examples {
-		doc := fmt.Sprintf(`date = %s`, example.in)
+		doc := "date = " + example.in
 
 		t.Run(fmt.Sprintf("ToLocalDateTime_%d_%s", i, example.name), func(t *testing.T) {
 			type dateStruct struct {
@@ -1621,7 +1617,7 @@ func TestUnmarshalLocalTime(t *testing.T) {
 	}
 
 	for i, example := range examples {
-		doc := fmt.Sprintf(`Time = %s`, example.in)
+		doc := "Time = " + example.in
 
 		t.Run(fmt.Sprintf("ToLocalTime_%d_%s", i, example.name), func(t *testing.T) {
 			type dateStruct struct {
@@ -1906,19 +1902,12 @@ func TestUnmarshalMixedTypeSlice(t *testing.T) {
 		ArrayField []interface{}
 	}
 
-	//doc := []byte(`ArrayField = [3.14,100,true,"hello world",{Field = "inner1"},[{Field = "inner2"},{Field = "inner3"}]]
-	//`)
-
 	doc := []byte(`ArrayField = [{Field = "inner1"},[{Field = "inner2"},{Field = "inner3"}]]
 `)
 
 	actual := TestStruct{}
 	expected := TestStruct{
 		ArrayField: []interface{}{
-			//3.14,
-			//int64(100),
-			//true,
-			//"hello world",
 			map[string]interface{}{
 				"Field": "inner1",
 			},
@@ -2004,7 +1993,8 @@ func TestDecoderStrict(t *testing.T) {
 		"Expected a *toml.StrictMissingError, got: %v", reflect.TypeOf(err),
 	)
 
-	se := err.(*toml.StrictMissingError)
+	var se *toml.StrictMissingError
+	assert.True(t, errors.As(err, &se))
 
 	keys := []toml.Key{}
 
@@ -2026,6 +2016,7 @@ func TestDecoderStrict(t *testing.T) {
 
 	var m map[string]interface{}
 	err = decoder(input).Decode(&m)
+	assert.NoError(t, err)
 }
 
 func TestDecoderStrictValid(t *testing.T) {
@@ -2062,19 +2053,6 @@ func (d *docUnmarshalTOML) UnmarshalTOML(i interface{}) error {
 	return nil
 }
 
-func TestDecoderStrictCustomUnmarshal(t *testing.T) {
-	t.Skip()
-	//input := `key = "ok"`
-	//var doc docUnmarshalTOML
-	//err := NewDecoder(bytes.NewReader([]byte(input))).Strict(true).Decode(&doc)
-	//if err != nil {
-	//	t.Fatal("unexpected error:", err)
-	//}
-	//if doc.Decoded.Key != "ok" {
-	//	t.Errorf("Bad unmarshal: expected ok, got %v", doc.Decoded.Key)
-	//}
-}
-
 type parent struct {
 	Doc        docUnmarshalTOML
 	DocPointer *docUnmarshalTOML
@@ -2278,7 +2256,7 @@ type Custom struct {
 	v string
 }
 
-func (c *Custom) UnmarshalTOML(v interface{}) error {
+func (c *Custom) UnmarshalTOML(interface{}) error {
 	c.v = "called"
 	return nil
 }
@@ -2303,14 +2281,14 @@ type durationString struct {
 	time.Duration
 }
 
-func (d *durationString) UnmarshalTOML(v interface{}) error {
+func (d *durationString) UnmarshalTOML(interface{}) error {
 	d.Duration = 10 * time.Second
 	return nil
 }
 
 type config437Error struct{}
 
-func (e *config437Error) UnmarshalTOML(v interface{}) error {
+func (e *config437Error) UnmarshalTOML(interface{}) error {
 	return errors.New("expected")
 }
 

internal/testsuite/add.go

@@ -3,17 +3,18 @@ package testsuite
 import (
 	"fmt"
 	"math"
+	"strconv"
 	"time"
 
 	"github.com/pelletier/go-toml/v2"
 )
 
 // addTag adds JSON tags to a data structure as expected by toml-test.
-func addTag(key string, tomlData interface{}) interface{} {
+func addTag(tomlData interface{}) interface{} {
 	// Switch on the data type.
 	switch orig := tomlData.(type) {
 	default:
-		//return map[string]interface{}{}
+		// return map[string]interface{}{}
 		panic(fmt.Sprintf("Unknown type: %T", tomlData))
 
 	// A table: we don't need to add any tags, just recurse for every table
@@ -21,7 +22,7 @@ func addTag(key string, tomlData interface{}) interface{} {
 	case map[string]interface{}:
 		typed := make(map[string]interface{}, len(orig))
 		for k, v := range orig {
-			typed[k] = addTag(k, v)
+			typed[k] = addTag(v)
 		}
 		return typed
 
@@ -30,13 +31,13 @@ func addTag(key string, tomlData interface{}) interface{} {
 	case []map[string]interface{}:
 		typed := make([]map[string]interface{}, len(orig))
 		for i, v := range orig {
-			typed[i] = addTag("", v).(map[string]interface{})
+			typed[i] = addTag(v).(map[string]interface{})
 		}
 		return typed
 	case []interface{}:
 		typed := make([]interface{}, len(orig))
 		for i, v := range orig {
-			typed[i] = addTag("", v)
+			typed[i] = addTag(v)
 		}
 		return typed
 
@@ -52,11 +53,11 @@ func addTag(key string, tomlData interface{}) interface{} {
 
 	// Tag primitive values: bool, string, int, and float64.
 	case bool:
-		return tag("bool", fmt.Sprintf("%v", orig))
+		return tag("bool", strconv.FormatBool(orig))
 	case string:
 		return tag("string", orig)
 	case int64:
-		return tag("integer", fmt.Sprintf("%d", orig))
+		return tag("integer", strconv.FormatInt(orig, 10))
 	case float64:
 		// Special case for nan since NaN == NaN is false.
 		if math.IsNaN(orig) {

internal/testsuite/json.go

@@ -9,6 +9,7 @@ import (
 )
 
 func CmpJSON(t *testing.T, key string, want, have interface{}) {
+	t.Helper()
 	switch w := want.(type) {
 	case map[string]interface{}:
 		cmpJSONMaps(t, key, w, have)
@@ -22,6 +23,7 @@ func CmpJSON(t *testing.T, key string, want, have interface{}) {
 }
 
 func cmpJSONMaps(t *testing.T, key string, want map[string]interface{}, have interface{}) {
+	t.Helper()
 	haveMap, ok := have.(map[string]interface{})
 	if !ok {
 		mismatch(t, key, "table", want, haveMap)
@@ -61,6 +63,7 @@ func cmpJSONMaps(t *testing.T, key string, want map[string]interface{}, have int
 }
 
 func cmpJSONArrays(t *testing.T, key string, want, have interface{}) {
+	t.Helper()
 	wantSlice, ok := want.([]interface{})
 	if !ok {
 		panic(fmt.Sprintf("'value' should be a JSON array when 'type=array', but it is a %T", want))
@@ -83,6 +86,7 @@ func cmpJSONArrays(t *testing.T, key string, want, have interface{}) {
 }
 
 func cmpJSONValues(t *testing.T, key string, want, have map[string]interface{}) {
+	t.Helper()
 	wantType, ok := want["type"].(string)
 	if !ok {
 		panic(fmt.Sprintf("'type' should be a string, but it is a %T", want["type"]))
@@ -126,6 +130,7 @@ func cmpJSONValues(t *testing.T, key string, want, have map[string]interface{})
 }
 
 func cmpAsStrings(t *testing.T, key string, want, have string) {
+	t.Helper()
 	if want != have {
 		t.Fatalf("Values for key '%s' don't match:\n"+
 			"  Expected:     %s\n"+
@@ -135,6 +140,7 @@ func cmpAsStrings(t *testing.T, key string, want, have string) {
 }
 
 func cmpFloats(t *testing.T, key string, want, have string) {
+	t.Helper()
 	// Special case for NaN, since NaN != NaN.
 	if strings.HasSuffix(want, "nan") || strings.HasSuffix(have, "nan") {
 		if want != have {
@@ -177,6 +183,7 @@ var layouts = map[string]string{
 }
 
 func cmpAsDatetimes(t *testing.T, key string, kind, want, have string) {
+	t.Helper()
 	layout, ok := layouts[kind]
 	if !ok {
 		panic("should never happen")
@@ -200,15 +207,6 @@ func cmpAsDatetimes(t *testing.T, key string, kind, want, have string) {
 	}
 }
 
-func cmpAsDatetimesLocal(t *testing.T, key string, want, have string) {
-	if datetimeRepl.Replace(want) != datetimeRepl.Replace(have) {
-		t.Fatalf("Values for key '%s' don't match:\n"+
-			"  Expected:     %v\n"+
-			"  Your encoder: %v",
-			key, want, have)
-	}
-}
-
 func kjoin(old, key string) string {
 	if len(old) == 0 {
 		return key
@@ -230,6 +228,7 @@ func isValue(m map[string]interface{}) bool {
 }
 
 func mismatch(t *testing.T, key string, wantType string, want, have interface{}) {
+	t.Helper()
 	t.Fatalf("Key '%s' is not an %s but %[4]T:\n"+
 		"  Expected:     %#[3]v\n"+
 		"  Your encoder: %#[4]v",
@@ -237,8 +236,9 @@ func mismatch(t *testing.T, key string, wantType string, want, have interface{})
 }
 
 func valMismatch(t *testing.T, key string, wantType, haveType string, want, have interface{}) {
+	t.Helper()
 	t.Fatalf("Key '%s' is not an %s but %s:\n"+
 		"  Expected:     %#[3]v\n"+
 		"  Your encoder: %#[4]v",
-		key, wantType, want, have)
+		key, wantType, haveType, want, have)
 }

internal/testsuite/parser.go

@@ -1,69 +0,0 @@
-package testsuite
-
-import (
-	"bytes"
-	"encoding/json"
-	"fmt"
-
-	"github.com/pelletier/go-toml/v2"
-)
-
-type parser struct{}
-
-func (p parser) Decode(input string) (output string, outputIsError bool, retErr error) {
-	defer func() {
-		if r := recover(); r != nil {
-			switch rr := r.(type) {
-			case error:
-				retErr = rr
-			default:
-				retErr = fmt.Errorf("%s", rr)
-			}
-		}
-	}()
-
-	var v interface{}
-
-	if err := toml.Unmarshal([]byte(input), &v); err != nil {
-		return err.Error(), true, nil
-	}
-
-	j, err := json.MarshalIndent(addTag("", v), "", "  ")
-	if err != nil {
-		return "", false, retErr
-	}
-
-	return string(j), false, retErr
-}
-
-func (p parser) Encode(input string) (output string, outputIsError bool, retErr error) {
-	defer func() {
-		if r := recover(); r != nil {
-			switch rr := r.(type) {
-			case error:
-				retErr = rr
-			default:
-				retErr = fmt.Errorf("%s", rr)
-			}
-		}
-	}()
-
-	var tmp interface{}
-	err := json.Unmarshal([]byte(input), &tmp)
-	if err != nil {
-		return "", false, err
-	}
-
-	rm, err := rmTag(tmp)
-	if err != nil {
-		return err.Error(), true, retErr
-	}
-
-	buf := new(bytes.Buffer)
-	err = toml.NewEncoder(buf).Encode(rm)
-	if err != nil {
-		return err.Error(), true, retErr
-	}
-
-	return buf.String(), false, retErr
-}

internal/testsuite/rm.go

@@ -9,7 +9,7 @@ import (
 )
 
 // Remove JSON tags to a data structure as returned by toml-test.
-func rmTag(typedJson interface{}) (interface{}, error) {
+func rmTag(typedJSON interface{}) (interface{}, error) {
 	// Check if key is in the table m.
 	in := func(key string, m map[string]interface{}) bool {
 		_, ok := m[key]
@@ -17,8 +17,7 @@ func rmTag(typedJson interface{}) (interface{}, error) {
 	}
 
 	// Switch on the data type.
-	switch v := typedJson.(type) {
-
+	switch v := typedJSON.(type) {
 	// Object: this can either be a TOML table or a primitive with tags.
 	case map[string]interface{}:
 		// This value represents a primitive: remove the tags and return just
@@ -56,7 +55,7 @@ func rmTag(typedJson interface{}) (interface{}, error) {
 	}
 
 	// The top level must be an object or array.
-	return nil, fmt.Errorf("unrecognized JSON format '%T'", typedJson)
+	return nil, fmt.Errorf("unrecognized JSON format '%T'", typedJSON)
 }
 
 // Return a primitive: read the "type" and convert the "value" to that.
@@ -79,7 +78,7 @@ func untag(typed map[string]interface{}) (interface{}, error) {
 		}
 		return f, nil
 
-		//toml.LocalDate{Year:2020, Month:12, Day:12}
+		// toml.LocalDate{Year:2020, Month:12, Day:12}
 	case "datetime":
 		return time.Parse("2006-01-02T15:04:05.999999999Z07:00", v)
 	case "datetime-local":
@@ -115,15 +114,3 @@ func untag(typed map[string]interface{}) (interface{}, error) {
 
 	return nil, fmt.Errorf("untag: unrecognized tag type %q", t)
 }
-
-func parseTime(v, format string, local bool) (t time.Time, err error) {
-	if local {
-		t, err = time.ParseInLocation(format, v, time.Local)
-	} else {
-		t, err = time.Parse(format, v)
-	}
-	if err != nil {
-		return time.Time{}, fmt.Errorf("Could not parse %q as a datetime: %w", v, err)
-	}
-	return t, nil
-}

internal/testsuite/testsuite.go

@@ -27,7 +27,7 @@ func Unmarshal(data []byte, v interface{}) error {
 // ValueToTaggedJSON takes a data structure and returns the tagged JSON
 // representation.
 func ValueToTaggedJSON(doc interface{}) ([]byte, error) {
-	return json.MarshalIndent(addTag("", doc), "", "  ")
+	return json.MarshalIndent(addTag(doc), "", "  ")
 }
 
 // DecodeStdin is a helper function for the toml-test binary interface.  TOML input
@@ -37,13 +37,13 @@ func DecodeStdin() error {
 	var decoded map[string]interface{}
 
 	if err := toml.NewDecoder(os.Stdin).Decode(&decoded); err != nil {
-		return fmt.Errorf("Error decoding TOML: %s", err)
+		return fmt.Errorf("error decoding TOML: %w", err)
 	}
 
 	j := json.NewEncoder(os.Stdout)
 	j.SetIndent("", "  ")
-	if err := j.Encode(addTag("", decoded)); err != nil {
-		return fmt.Errorf("Error encoding JSON: %s", err)
+	if err := j.Encode(addTag(decoded)); err != nil {
+		return fmt.Errorf("error encoding JSON: %w", err)
 	}
 
 	return nil

internal/tracker/key.go

@@ -36,7 +36,7 @@ func (t *KeyTracker) Pop(node *unstable.Node) {
 	}
 }
 
-// Key returns the current key
+// Key returns the current key.
 func (t *KeyTracker) Key() []string {
 	k := make([]string, len(t.k))
 	copy(k, t.k)

internal/tracker/seen.go

@@ -288,11 +288,12 @@ func (s *SeenTracker) checkKeyValue(node *unstable.Node) (bool, error) {
 			idx = s.create(parentIdx, k, tableKind, false, true)
 		} else {
 			entry := s.entries[idx]
-			if it.IsLast() {
+			switch {
+			case it.IsLast():
 				return false, fmt.Errorf("toml: key %s is already defined", string(k))
-			} else if entry.kind != tableKind {
+			case entry.kind != tableKind:
 				return false, fmt.Errorf("toml: expected %s to be a table, not a %s", string(k), entry.kind)
-			} else if entry.explicit {
+			case entry.explicit:
 				return false, fmt.Errorf("toml: cannot redefine table %s that has already been explicitly defined", string(k))
 			}
 		}
@@ -309,16 +310,16 @@ func (s *SeenTracker) checkKeyValue(node *unstable.Node) (bool, error) {
 		return s.checkInlineTable(value)
 	case unstable.Array:
 		return s.checkArray(value)
+	default:
+		return false, nil
 	}
-
-	return false, nil
 }
 
 func (s *SeenTracker) checkArray(node *unstable.Node) (first bool, err error) {
 	it := node.Children()
 	for it.Next() {
 		n := it.Node()
-		switch n.Kind {
+		switch n.Kind { //nolint:exhaustive
 		case unstable.InlineTable:
 			first, err = s.checkInlineTable(n)
 			if err != nil {

internal/tracker/tracker.go

@@ -1 +1,2 @@
+// Package tracker provides functions for keeping track of AST nodes.
 package tracker