Reset gojson to golang/go|1.23.4 [removes all custom changes]

gojson/LICENSE

@@ -1,27 +0,0 @@
-Copyright (c) 2009 The Go Authors. All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-   * Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above
-copyright notice, this list of conditions and the following disclaimer
-in the documentation and/or other materials provided with the
-distribution.
-   * Neither the name of Google Inc. nor the names of its
-contributors may be used to endorse or promote products derived from
-this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

gojson/bench_test.go

@@ -0,0 +1,584 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Large data benchmark.
+// The JSON data is a summary of agl's changes in the
+// go, webkit, and chromium open source projects.
+// We benchmark converting between the JSON form
+// and in-memory data structures.
+
+package json
+
+import (
+	"bytes"
+	"compress/gzip"
+	"fmt"
+	"internal/testenv"
+	"io"
+	"os"
+	"reflect"
+	"regexp"
+	"runtime"
+	"strings"
+	"sync"
+	"testing"
+)
+
+type codeResponse struct {
+	Tree     *codeNode `json:"tree"`
+	Username string    `json:"username"`
+}
+
+type codeNode struct {
+	Name     string      `json:"name"`
+	Kids     []*codeNode `json:"kids"`
+	CLWeight float64     `json:"cl_weight"`
+	Touches  int         `json:"touches"`
+	MinT     int64       `json:"min_t"`
+	MaxT     int64       `json:"max_t"`
+	MeanT    int64       `json:"mean_t"`
+}
+
+var codeJSON []byte
+var codeStruct codeResponse
+
+func codeInit() {
+	f, err := os.Open("testdata/code.json.gz")
+	if err != nil {
+		panic(err)
+	}
+	defer f.Close()
+	gz, err := gzip.NewReader(f)
+	if err != nil {
+		panic(err)
+	}
+	data, err := io.ReadAll(gz)
+	if err != nil {
+		panic(err)
+	}
+
+	codeJSON = data
+
+	if err := Unmarshal(codeJSON, &codeStruct); err != nil {
+		panic("unmarshal code.json: " + err.Error())
+	}
+
+	if data, err = Marshal(&codeStruct); err != nil {
+		panic("marshal code.json: " + err.Error())
+	}
+
+	if !bytes.Equal(data, codeJSON) {
+		println("different lengths", len(data), len(codeJSON))
+		for i := 0; i < len(data) && i < len(codeJSON); i++ {
+			if data[i] != codeJSON[i] {
+				println("re-marshal: changed at byte", i)
+				println("orig: ", string(codeJSON[i-10:i+10]))
+				println("new: ", string(data[i-10:i+10]))
+				break
+			}
+		}
+		panic("re-marshal code.json: different result")
+	}
+}
+
+func BenchmarkCodeEncoder(b *testing.B) {
+	b.ReportAllocs()
+	if codeJSON == nil {
+		b.StopTimer()
+		codeInit()
+		b.StartTimer()
+	}
+	b.RunParallel(func(pb *testing.PB) {
+		enc := NewEncoder(io.Discard)
+		for pb.Next() {
+			if err := enc.Encode(&codeStruct); err != nil {
+				b.Fatalf("Encode error: %v", err)
+			}
+		}
+	})
+	b.SetBytes(int64(len(codeJSON)))
+}
+
+func BenchmarkCodeEncoderError(b *testing.B) {
+	b.ReportAllocs()
+	if codeJSON == nil {
+		b.StopTimer()
+		codeInit()
+		b.StartTimer()
+	}
+
+	// Trigger an error in Marshal with cyclic data.
+	type Dummy struct {
+		Name string
+		Next *Dummy
+	}
+	dummy := Dummy{Name: "Dummy"}
+	dummy.Next = &dummy
+
+	b.RunParallel(func(pb *testing.PB) {
+		enc := NewEncoder(io.Discard)
+		for pb.Next() {
+			if err := enc.Encode(&codeStruct); err != nil {
+				b.Fatalf("Encode error: %v", err)
+			}
+			if _, err := Marshal(dummy); err == nil {
+				b.Fatal("Marshal error: got nil, want non-nil")
+			}
+		}
+	})
+	b.SetBytes(int64(len(codeJSON)))
+}
+
+func BenchmarkCodeMarshal(b *testing.B) {
+	b.ReportAllocs()
+	if codeJSON == nil {
+		b.StopTimer()
+		codeInit()
+		b.StartTimer()
+	}
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			if _, err := Marshal(&codeStruct); err != nil {
+				b.Fatalf("Marshal error: %v", err)
+			}
+		}
+	})
+	b.SetBytes(int64(len(codeJSON)))
+}
+
+func BenchmarkCodeMarshalError(b *testing.B) {
+	b.ReportAllocs()
+	if codeJSON == nil {
+		b.StopTimer()
+		codeInit()
+		b.StartTimer()
+	}
+
+	// Trigger an error in Marshal with cyclic data.
+	type Dummy struct {
+		Name string
+		Next *Dummy
+	}
+	dummy := Dummy{Name: "Dummy"}
+	dummy.Next = &dummy
+
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			if _, err := Marshal(&codeStruct); err != nil {
+				b.Fatalf("Marshal error: %v", err)
+			}
+			if _, err := Marshal(dummy); err == nil {
+				b.Fatal("Marshal error: got nil, want non-nil")
+			}
+		}
+	})
+	b.SetBytes(int64(len(codeJSON)))
+}
+
+func benchMarshalBytes(n int) func(*testing.B) {
+	sample := []byte("hello world")
+	// Use a struct pointer, to avoid an allocation when passing it as an
+	// interface parameter to Marshal.
+	v := &struct {
+		Bytes []byte
+	}{
+		bytes.Repeat(sample, (n/len(sample))+1)[:n],
+	}
+	return func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			if _, err := Marshal(v); err != nil {
+				b.Fatalf("Marshal error: %v", err)
+			}
+		}
+	}
+}
+
+func benchMarshalBytesError(n int) func(*testing.B) {
+	sample := []byte("hello world")
+	// Use a struct pointer, to avoid an allocation when passing it as an
+	// interface parameter to Marshal.
+	v := &struct {
+		Bytes []byte
+	}{
+		bytes.Repeat(sample, (n/len(sample))+1)[:n],
+	}
+
+	// Trigger an error in Marshal with cyclic data.
+	type Dummy struct {
+		Name string
+		Next *Dummy
+	}
+	dummy := Dummy{Name: "Dummy"}
+	dummy.Next = &dummy
+
+	return func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			if _, err := Marshal(v); err != nil {
+				b.Fatalf("Marshal error: %v", err)
+			}
+			if _, err := Marshal(dummy); err == nil {
+				b.Fatal("Marshal error: got nil, want non-nil")
+			}
+		}
+	}
+}
+
+func BenchmarkMarshalBytes(b *testing.B) {
+	b.ReportAllocs()
+	// 32 fits within encodeState.scratch.
+	b.Run("32", benchMarshalBytes(32))
+	// 256 doesn't fit in encodeState.scratch, but is small enough to
+	// allocate and avoid the slower base64.NewEncoder.
+	b.Run("256", benchMarshalBytes(256))
+	// 4096 is large enough that we want to avoid allocating for it.
+	b.Run("4096", benchMarshalBytes(4096))
+}
+
+func BenchmarkMarshalBytesError(b *testing.B) {
+	b.ReportAllocs()
+	// 32 fits within encodeState.scratch.
+	b.Run("32", benchMarshalBytesError(32))
+	// 256 doesn't fit in encodeState.scratch, but is small enough to
+	// allocate and avoid the slower base64.NewEncoder.
+	b.Run("256", benchMarshalBytesError(256))
+	// 4096 is large enough that we want to avoid allocating for it.
+	b.Run("4096", benchMarshalBytesError(4096))
+}
+
+func BenchmarkMarshalMap(b *testing.B) {
+	b.ReportAllocs()
+	m := map[string]int{
+		"key3": 3,
+		"key2": 2,
+		"key1": 1,
+	}
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			if _, err := Marshal(m); err != nil {
+				b.Fatal("Marshal:", err)
+			}
+		}
+	})
+}
+
+func BenchmarkCodeDecoder(b *testing.B) {
+	b.ReportAllocs()
+	if codeJSON == nil {
+		b.StopTimer()
+		codeInit()
+		b.StartTimer()
+	}
+	b.RunParallel(func(pb *testing.PB) {
+		var buf bytes.Buffer
+		dec := NewDecoder(&buf)
+		var r codeResponse
+		for pb.Next() {
+			buf.Write(codeJSON)
+			// hide EOF
+			buf.WriteByte('\n')
+			buf.WriteByte('\n')
+			buf.WriteByte('\n')
+			if err := dec.Decode(&r); err != nil {
+				b.Fatalf("Decode error: %v", err)
+			}
+		}
+	})
+	b.SetBytes(int64(len(codeJSON)))
+}
+
+func BenchmarkUnicodeDecoder(b *testing.B) {
+	b.ReportAllocs()
+	j := []byte(`"\uD83D\uDE01"`)
+	b.SetBytes(int64(len(j)))
+	r := bytes.NewReader(j)
+	dec := NewDecoder(r)
+	var out string
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		if err := dec.Decode(&out); err != nil {
+			b.Fatalf("Decode error: %v", err)
+		}
+		r.Seek(0, 0)
+	}
+}
+
+func BenchmarkDecoderStream(b *testing.B) {
+	b.ReportAllocs()
+	b.StopTimer()
+	var buf bytes.Buffer
+	dec := NewDecoder(&buf)
+	buf.WriteString(`"` + strings.Repeat("x", 1000000) + `"` + "\n\n\n")
+	var x any
+	if err := dec.Decode(&x); err != nil {
+		b.Fatalf("Decode error: %v", err)
+	}
+	ones := strings.Repeat(" 1\n", 300000) + "\n\n\n"
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		if i%300000 == 0 {
+			buf.WriteString(ones)
+		}
+		x = nil
+		switch err := dec.Decode(&x); {
+		case err != nil:
+			b.Fatalf("Decode error: %v", err)
+		case x != 1.0:
+			b.Fatalf("Decode: got %v want 1.0", i)
+		}
+	}
+}
+
+func BenchmarkCodeUnmarshal(b *testing.B) {
+	b.ReportAllocs()
+	if codeJSON == nil {
+		b.StopTimer()
+		codeInit()
+		b.StartTimer()
+	}
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			var r codeResponse
+			if err := Unmarshal(codeJSON, &r); err != nil {
+				b.Fatalf("Unmarshal error: %v", err)
+			}
+		}
+	})
+	b.SetBytes(int64(len(codeJSON)))
+}
+
+func BenchmarkCodeUnmarshalReuse(b *testing.B) {
+	b.ReportAllocs()
+	if codeJSON == nil {
+		b.StopTimer()
+		codeInit()
+		b.StartTimer()
+	}
+	b.RunParallel(func(pb *testing.PB) {
+		var r codeResponse
+		for pb.Next() {
+			if err := Unmarshal(codeJSON, &r); err != nil {
+				b.Fatalf("Unmarshal error: %v", err)
+			}
+		}
+	})
+	b.SetBytes(int64(len(codeJSON)))
+}
+
+func BenchmarkUnmarshalString(b *testing.B) {
+	b.ReportAllocs()
+	data := []byte(`"hello, world"`)
+	b.RunParallel(func(pb *testing.PB) {
+		var s string
+		for pb.Next() {
+			if err := Unmarshal(data, &s); err != nil {
+				b.Fatalf("Unmarshal error: %v", err)
+			}
+		}
+	})
+}
+
+func BenchmarkUnmarshalFloat64(b *testing.B) {
+	b.ReportAllocs()
+	data := []byte(`3.14`)
+	b.RunParallel(func(pb *testing.PB) {
+		var f float64
+		for pb.Next() {
+			if err := Unmarshal(data, &f); err != nil {
+				b.Fatalf("Unmarshal error: %v", err)
+			}
+		}
+	})
+}
+
+func BenchmarkUnmarshalInt64(b *testing.B) {
+	b.ReportAllocs()
+	data := []byte(`3`)
+	b.RunParallel(func(pb *testing.PB) {
+		var x int64
+		for pb.Next() {
+			if err := Unmarshal(data, &x); err != nil {
+				b.Fatalf("Unmarshal error: %v", err)
+			}
+		}
+	})
+}
+
+func BenchmarkUnmarshalMap(b *testing.B) {
+	b.ReportAllocs()
+	data := []byte(`{"key1":"value1","key2":"value2","key3":"value3"}`)
+	b.RunParallel(func(pb *testing.PB) {
+		x := make(map[string]string, 3)
+		for pb.Next() {
+			if err := Unmarshal(data, &x); err != nil {
+				b.Fatalf("Unmarshal error: %v", err)
+			}
+		}
+	})
+}
+
+func BenchmarkIssue10335(b *testing.B) {
+	b.ReportAllocs()
+	j := []byte(`{"a":{ }}`)
+	b.RunParallel(func(pb *testing.PB) {
+		var s struct{}
+		for pb.Next() {
+			if err := Unmarshal(j, &s); err != nil {
+				b.Fatalf("Unmarshal error: %v", err)
+			}
+		}
+	})
+}
+
+func BenchmarkIssue34127(b *testing.B) {
+	b.ReportAllocs()
+	j := struct {
+		Bar string `json:"bar,string"`
+	}{
+		Bar: `foobar`,
+	}
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			if _, err := Marshal(&j); err != nil {
+				b.Fatalf("Marshal error: %v", err)
+			}
+		}
+	})
+}
+
+func BenchmarkUnmapped(b *testing.B) {
+	b.ReportAllocs()
+	j := []byte(`{"s": "hello", "y": 2, "o": {"x": 0}, "a": [1, 99, {"x": 1}]}`)
+	b.RunParallel(func(pb *testing.PB) {
+		var s struct{}
+		for pb.Next() {
+			if err := Unmarshal(j, &s); err != nil {
+				b.Fatalf("Unmarshal error: %v", err)
+			}
+		}
+	})
+}
+
+func BenchmarkTypeFieldsCache(b *testing.B) {
+	b.ReportAllocs()
+	var maxTypes int = 1e6
+	if testenv.Builder() != "" {
+		maxTypes = 1e3 // restrict cache sizes on builders
+	}
+
+	// Dynamically generate many new types.
+	types := make([]reflect.Type, maxTypes)
+	fs := []reflect.StructField{{
+		Type:  reflect.TypeFor[string](),
+		Index: []int{0},
+	}}
+	for i := range types {
+		fs[0].Name = fmt.Sprintf("TypeFieldsCache%d", i)
+		types[i] = reflect.StructOf(fs)
+	}
+
+	// clearClear clears the cache. Other JSON operations, must not be running.
+	clearCache := func() {
+		fieldCache = sync.Map{}
+	}
+
+	// MissTypes tests the performance of repeated cache misses.
+	// This measures the time to rebuild a cache of size nt.
+	for nt := 1; nt <= maxTypes; nt *= 10 {
+		ts := types[:nt]
+		b.Run(fmt.Sprintf("MissTypes%d", nt), func(b *testing.B) {
+			nc := runtime.GOMAXPROCS(0)
+			for i := 0; i < b.N; i++ {
+				clearCache()
+				var wg sync.WaitGroup
+				for j := 0; j < nc; j++ {
+					wg.Add(1)
+					go func(j int) {
+						for _, t := range ts[(j*len(ts))/nc : ((j+1)*len(ts))/nc] {
+							cachedTypeFields(t)
+						}
+						wg.Done()
+					}(j)
+				}
+				wg.Wait()
+			}
+		})
+	}
+
+	// HitTypes tests the performance of repeated cache hits.
+	// This measures the average time of each cache lookup.
+	for nt := 1; nt <= maxTypes; nt *= 10 {
+		// Pre-warm a cache of size nt.
+		clearCache()
+		for _, t := range types[:nt] {
+			cachedTypeFields(t)
+		}
+		b.Run(fmt.Sprintf("HitTypes%d", nt), func(b *testing.B) {
+			b.RunParallel(func(pb *testing.PB) {
+				for pb.Next() {
+					cachedTypeFields(types[0])
+				}
+			})
+		})
+	}
+}
+
+func BenchmarkEncodeMarshaler(b *testing.B) {
+	b.ReportAllocs()
+
+	m := struct {
+		A int
+		B RawMessage
+	}{}
+
+	b.RunParallel(func(pb *testing.PB) {
+		enc := NewEncoder(io.Discard)
+
+		for pb.Next() {
+			if err := enc.Encode(&m); err != nil {
+				b.Fatalf("Encode error: %v", err)
+			}
+		}
+	})
+}
+
+func BenchmarkEncoderEncode(b *testing.B) {
+	b.ReportAllocs()
+	type T struct {
+		X, Y string
+	}
+	v := &T{"foo", "bar"}
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			if err := NewEncoder(io.Discard).Encode(v); err != nil {
+				b.Fatalf("Encode error: %v", err)
+			}
+		}
+	})
+}
+
+func BenchmarkNumberIsValid(b *testing.B) {
+	s := "-61657.61667E+61673"
+	for i := 0; i < b.N; i++ {
+		isValidNumber(s)
+	}
+}
+
+func BenchmarkNumberIsValidRegexp(b *testing.B) {
+	var jsonNumberRegexp = regexp.MustCompile(`^-?(?:0|[1-9]\d*)(?:\.\d+)?(?:[eE][+-]?\d+)?$`)
+	s := "-61657.61667E+61673"
+	for i := 0; i < b.N; i++ {
+		jsonNumberRegexp.MatchString(s)
+	}
+}
+
+func BenchmarkUnmarshalNumber(b *testing.B) {
+	b.ReportAllocs()
+	data := []byte(`"-61657.61667E+61673"`)
+	var number Number
+	for i := 0; i < b.N; i++ {
+		if err := Unmarshal(data, &number); err != nil {
+			b.Fatal("Unmarshal:", err)
+		}
+	}
+}

gojson/decode.go

@@ -17,14 +17,15 @@ import (
 	"unicode"
 	"unicode/utf16"
 	"unicode/utf8"
+	_ "unsafe" // for linkname
 )
 
 // Unmarshal parses the JSON-encoded data and stores the result
 // in the value pointed to by v. If v is nil or not a pointer,
-// Unmarshal returns an InvalidUnmarshalError.
+// Unmarshal returns an [InvalidUnmarshalError].
 //
 // Unmarshal uses the inverse of the encodings that
-// Marshal uses, allocating maps, slices, and pointers as necessary,
+// [Marshal] uses, allocating maps, slices, and pointers as necessary,
 // with the following additional rules:
 //
 // To unmarshal JSON into a pointer, Unmarshal first handles the case of
@@ -33,28 +34,28 @@ import (
 // the value pointed at by the pointer. If the pointer is nil, Unmarshal
 // allocates a new value for it to point to.
 //
-// To unmarshal JSON into a value implementing the Unmarshaler interface,
+// To unmarshal JSON into a value implementing [Unmarshaler],
-// Unmarshal calls that value's UnmarshalJSON method, including
+// Unmarshal calls that value's [Unmarshaler.UnmarshalJSON] method, including
 // when the input is a JSON null.
-// Otherwise, if the value implements encoding.TextUnmarshaler
+// Otherwise, if the value implements [encoding.TextUnmarshaler]
-// and the input is a JSON quoted string, Unmarshal calls that value's
+// and the input is a JSON quoted string, Unmarshal calls
-// UnmarshalText method with the unquoted form of the string.
+// [encoding.TextUnmarshaler.UnmarshalText] with the unquoted form of the string.
 //
 // To unmarshal JSON into a struct, Unmarshal matches incoming object
-// keys to the keys used by Marshal (either the struct field name or its tag),
+// keys to the keys used by [Marshal] (either the struct field name or its tag),
 // preferring an exact match but also accepting a case-insensitive match. By
 // default, object keys which don't have a corresponding struct field are
-// ignored (see Decoder.DisallowUnknownFields for an alternative).
+// ignored (see [Decoder.DisallowUnknownFields] for an alternative).
 //
 // To unmarshal JSON into an interface value,
 // Unmarshal stores one of these in the interface value:
 //
-//	bool, for JSON booleans
+//   - bool, for JSON booleans
-//	float64, for JSON numbers
+//   - float64, for JSON numbers
-//	string, for JSON strings
+//   - string, for JSON strings
-//	[]interface{}, for JSON arrays
+//   - []interface{}, for JSON arrays
-//	map[string]interface{}, for JSON objects
+//   - map[string]interface{}, for JSON objects
-//	nil for JSON null
+//   - nil for JSON null
 //
 // To unmarshal a JSON array into a slice, Unmarshal resets the slice length
 // to zero and then appends each element to the slice.
@@ -72,16 +73,15 @@ import (
 // use. If the map is nil, Unmarshal allocates a new map. Otherwise Unmarshal
 // reuses the existing map, keeping existing entries. Unmarshal then stores
 // key-value pairs from the JSON object into the map. The map's key type must
-// either be any string type, an integer, implement json.Unmarshaler, or
+// either be any string type, an integer, or implement [encoding.TextUnmarshaler].
-// implement encoding.TextUnmarshaler.
 //
-// If the JSON-encoded data contain a syntax error, Unmarshal returns a SyntaxError.
+// If the JSON-encoded data contain a syntax error, Unmarshal returns a [SyntaxError].
 //
 // If a JSON value is not appropriate for a given target type,
 // or if a JSON number overflows the target type, Unmarshal
 // skips that field and completes the unmarshaling as best it can.
 // If no more serious errors are encountered, Unmarshal returns
-// an UnmarshalTypeError describing the earliest such error. In any
+// an [UnmarshalTypeError] describing the earliest such error. In any
 // case, it's not guaranteed that all the remaining fields following
 // the problematic one will be unmarshaled into the target object.
 //
@@ -114,7 +114,7 @@ func Unmarshal(data []byte, v any) error {
 // a JSON value. UnmarshalJSON must copy the JSON data
 // if it wishes to retain the data after returning.
 //
-// By convention, to approximate the behavior of Unmarshal itself,
+// By convention, to approximate the behavior of [Unmarshal] itself,
 // Unmarshalers implement UnmarshalJSON([]byte("null")) as a no-op.
 type Unmarshaler interface {
 	UnmarshalJSON([]byte) error
@@ -151,8 +151,8 @@ func (e *UnmarshalFieldError) Error() string {
 	return "json: cannot unmarshal object key " + strconv.Quote(e.Key) + " into unexported field " + e.Field.Name + " of type " + e.Type.String()
 }
 
-// An InvalidUnmarshalError describes an invalid argument passed to Unmarshal.
+// An InvalidUnmarshalError describes an invalid argument passed to [Unmarshal].
-// (The argument to Unmarshal must be a non-nil pointer.)
+// (The argument to [Unmarshal] must be a non-nil pointer.)
 type InvalidUnmarshalError struct {
 	Type reflect.Type
 }
@@ -217,7 +217,6 @@ type decodeState struct {
 	savedError            error
 	useNumber             bool
 	disallowUnknownFields bool
-	tagkey                *string
 }
 
 // readIndex returns the position of the last byte read.
@@ -541,17 +540,10 @@ func (d *decodeState) array(v reflect.Value) error {
 			break
 		}
 
-		// Get element of array, growing if necessary.
+		// Expand slice length, growing the slice if necessary.
 		if v.Kind() == reflect.Slice {
-			// Grow slice if necessary
 			if i >= v.Cap() {
-				newcap := v.Cap() + v.Cap()/2
+				v.Grow(1)
-				if newcap < 4 {
-					newcap = 4
-				}
-				newv := reflect.MakeSlice(v.Type(), v.Len(), newcap)
-				reflect.Copy(newv, v)
-				v.Set(newv)
 			}
 			if i >= v.Len() {
 				v.SetLen(i + 1)
@@ -585,13 +577,11 @@ func (d *decodeState) array(v reflect.Value) error {
 
 	if i < v.Len() {
 		if v.Kind() == reflect.Array {
-			// Array. Zero the rest.
-			z := reflect.Zero(v.Type().Elem())
 			for ; i < v.Len(); i++ {
-				v.Index(i).Set(z)
+				v.Index(i).SetZero() // zero remainder of array
 			}
 		} else {
-			v.SetLen(i)
+			v.SetLen(i) // truncate the slice
 		}
 	}
 	if i == 0 && v.Kind() == reflect.Slice {
@@ -601,7 +591,7 @@ func (d *decodeState) array(v reflect.Value) error {
 }
 
 var nullLiteral = []byte("null")
-var textUnmarshalerType = reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem()
+var textUnmarshalerType = reflect.TypeFor[encoding.TextUnmarshaler]()
 
 // object consumes an object from d.data[d.off-1:], decoding into v.
 // The first byte ('{') of the object has been read already.
@@ -653,11 +643,7 @@ func (d *decodeState) object(v reflect.Value) error {
 			v.Set(reflect.MakeMap(t))
 		}
 	case reflect.Struct:
-		tagkey := "json"
+		fields = cachedTypeFields(t)
-		if d.tagkey != nil {
-			tagkey = *d.tagkey
-		}
-		fields = cachedTypeFields(t, tagkey)
 		// ok
 	default:
 		d.saveError(&UnmarshalTypeError{Value: "object", Type: t, Offset: int64(d.off)})
@@ -700,24 +686,13 @@ func (d *decodeState) object(v reflect.Value) error {
 			if !mapElem.IsValid() {
 				mapElem = reflect.New(elemType).Elem()
 			} else {
-				mapElem.Set(reflect.Zero(elemType))
+				mapElem.SetZero()
 			}
 			subv = mapElem
 		} else {
-			var f *field
+			f := fields.byExactName[string(key)]
-			if i, ok := fields.nameIndex[string(key)]; ok {
+			if f == nil {
-				// Found an exact name match.
+				f = fields.byFoldedName[string(foldName(key))]
-				f = &fields.list[i]
-			} else {
-				// Fall back to the expensive case-insensitive
-				// linear search.
-				for i := range fields.list {
-					ff := &fields.list[i]
-					if ff.equalFold(ff.nameBytes, key) {
-						f = ff
-						break
-					}
-				}
 			}
 			if f != nil {
 				subv = v
@@ -787,33 +762,35 @@ func (d *decodeState) object(v reflect.Value) error {
 		if v.Kind() == reflect.Map {
 			kt := t.Key()
 			var kv reflect.Value
-			switch {
+			if reflect.PointerTo(kt).Implements(textUnmarshalerType) {
-			case reflect.PointerTo(kt).Implements(textUnmarshalerType):
 				kv = reflect.New(kt)
 				if err := d.literalStore(item, kv, true); err != nil {
 					return err
 				}
 				kv = kv.Elem()
-			case kt.Kind() == reflect.String:
+			} else {
-				kv = reflect.ValueOf(key).Convert(kt)
-			default:
 				switch kt.Kind() {
+				case reflect.String:
+					kv = reflect.New(kt).Elem()
+					kv.SetString(string(key))
 				case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
 					s := string(key)
 					n, err := strconv.ParseInt(s, 10, 64)
-					if err != nil || reflect.Zero(kt).OverflowInt(n) {
+					if err != nil || kt.OverflowInt(n) {
 						d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: kt, Offset: int64(start + 1)})
 						break
 					}
-					kv = reflect.ValueOf(n).Convert(kt)
+					kv = reflect.New(kt).Elem()
+					kv.SetInt(n)
 				case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
 					s := string(key)
 					n, err := strconv.ParseUint(s, 10, 64)
-					if err != nil || reflect.Zero(kt).OverflowUint(n) {
+					if err != nil || kt.OverflowUint(n) {
 						d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: kt, Offset: int64(start + 1)})
 						break
 					}
-					kv = reflect.ValueOf(n).Convert(kt)
+					kv = reflect.New(kt).Elem()
+					kv.SetUint(n)
 				default:
 					panic("json: Unexpected key type") // should never occur
 				}
@@ -852,12 +829,12 @@ func (d *decodeState) convertNumber(s string) (any, error) {
 	}
 	f, err := strconv.ParseFloat(s, 64)
 	if err != nil {
-		return nil, &UnmarshalTypeError{Value: "number " + s, Type: reflect.TypeOf(0.0), Offset: int64(d.off)}
+		return nil, &UnmarshalTypeError{Value: "number " + s, Type: reflect.TypeFor[float64](), Offset: int64(d.off)}
 	}
 	return f, nil
 }
 
-var numberType = reflect.TypeOf(Number(""))
+var numberType = reflect.TypeFor[Number]()
 
 // literalStore decodes a literal stored in item into v.
 //
@@ -867,7 +844,7 @@ var numberType = reflect.TypeOf(Number(""))
 func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool) error {
 	// Check for unmarshaler.
 	if len(item) == 0 {
-		//Empty string given
+		// Empty string given.
 		d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
 		return nil
 	}
@@ -914,7 +891,7 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 		}
 		switch v.Kind() {
 		case reflect.Interface, reflect.Pointer, reflect.Map, reflect.Slice:
-			v.Set(reflect.Zero(v.Type()))
+			v.SetZero()
 			// otherwise, ignore null for primitives/string
 		}
 	case 't', 'f': // true, false
@@ -966,10 +943,11 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 			}
 			v.SetBytes(b[:n])
 		case reflect.String:
-			if v.Type() == numberType && !isValidNumber(string(s)) {
+			t := string(s)
+			if v.Type() == numberType && !isValidNumber(t) {
 				return fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", item)
 			}
-			v.SetString(string(s))
+			v.SetString(t)
 		case reflect.Interface:
 			if v.NumMethod() == 0 {
 				v.Set(reflect.ValueOf(string(s)))
@@ -985,13 +963,12 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 			}
 			panic(phasePanicMsg)
 		}
-		s := string(item)
 		switch v.Kind() {
 		default:
 			if v.Kind() == reflect.String && v.Type() == numberType {
 				// s must be a valid number, because it's
 				// already been tokenized.
-				v.SetString(s)
+				v.SetString(string(item))
 				break
 			}
 			if fromQuoted {
@@ -999,7 +976,7 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 			}
 			d.saveError(&UnmarshalTypeError{Value: "number", Type: v.Type(), Offset: int64(d.readIndex())})
 		case reflect.Interface:
-			n, err := d.convertNumber(s)
+			n, err := d.convertNumber(string(item))
 			if err != nil {
 				d.saveError(err)
 				break
@@ -1011,25 +988,25 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 			v.Set(reflect.ValueOf(n))
 
 		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-			n, err := strconv.ParseInt(s, 10, 64)
+			n, err := strconv.ParseInt(string(item), 10, 64)
 			if err != nil || v.OverflowInt(n) {
-				d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: v.Type(), Offset: int64(d.readIndex())})
+				d.saveError(&UnmarshalTypeError{Value: "number " + string(item), Type: v.Type(), Offset: int64(d.readIndex())})
 				break
 			}
 			v.SetInt(n)
 
 		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
-			n, err := strconv.ParseUint(s, 10, 64)
+			n, err := strconv.ParseUint(string(item), 10, 64)
 			if err != nil || v.OverflowUint(n) {
-				d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: v.Type(), Offset: int64(d.readIndex())})
+				d.saveError(&UnmarshalTypeError{Value: "number " + string(item), Type: v.Type(), Offset: int64(d.readIndex())})
 				break
 			}
 			v.SetUint(n)
 
 		case reflect.Float32, reflect.Float64:
-			n, err := strconv.ParseFloat(s, v.Type().Bits())
+			n, err := strconv.ParseFloat(string(item), v.Type().Bits())
 			if err != nil || v.OverflowFloat(n) {
-				d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: v.Type(), Offset: int64(d.readIndex())})
+				d.saveError(&UnmarshalTypeError{Value: "number " + string(item), Type: v.Type(), Offset: int64(d.readIndex())})
 				break
 			}
 			v.SetFloat(n)
@@ -1201,6 +1178,15 @@ func unquote(s []byte) (t string, ok bool) {
 	return
 }
 
+// unquoteBytes should be an internal detail,
+// but widely used packages access it using linkname.
+// Notable members of the hall of shame include:
+//   - github.com/bytedance/sonic
+//
+// Do not remove or change the type signature.
+// See go.dev/issue/67401.
+//
+//go:linkname unquoteBytes
 func unquoteBytes(s []byte) (t []byte, ok bool) {
 	if len(s) < 2 || s[0] != '"' || s[len(s)-1] != '"' {
 		return

gojson/fold.go

@@ -5,140 +5,44 @@
 package json
 
 import (
-	"bytes"
+	"unicode"
 	"unicode/utf8"
 )
 
-const (
+// foldName returns a folded string such that foldName(x) == foldName(y)
-	caseMask     = ^byte(0x20) // Mask to ignore case in ASCII.
+// is identical to bytes.EqualFold(x, y).
-	kelvin       = '\u212a'
+func foldName(in []byte) []byte {
-	smallLongEss = '\u017f'
+	// This is inlinable to take advantage of "function outlining".
-)
+	var arr [32]byte // large enough for most JSON names
-
+	return appendFoldedName(arr[:0], in)
-// foldFunc returns one of four different case folding equivalence
-// functions, from most general (and slow) to fastest:
-//
-// 1) bytes.EqualFold, if the key s contains any non-ASCII UTF-8
-// 2) equalFoldRight, if s contains special folding ASCII ('k', 'K', 's', 'S')
-// 3) asciiEqualFold, no special, but includes non-letters (including _)
-// 4) simpleLetterEqualFold, no specials, no non-letters.
-//
-// The letters S and K are special because they map to 3 runes, not just 2:
-//   - S maps to s and to U+017F 'ſ' Latin small letter long s
-//   - k maps to K and to U+212A 'K' Kelvin sign
-//
-// See https://play.golang.org/p/tTxjOc0OGo
-//
-// The returned function is specialized for matching against s and
-// should only be given s. It's not curried for performance reasons.
-func foldFunc(s []byte) func(s, t []byte) bool {
-	nonLetter := false
-	special := false // special letter
-	for _, b := range s {
-		if b >= utf8.RuneSelf {
-			return bytes.EqualFold
-		}
-		upper := b & caseMask
-		if upper < 'A' || upper > 'Z' {
-			nonLetter = true
-		} else if upper == 'K' || upper == 'S' {
-			// See above for why these letters are special.
-			special = true
-		}
-	}
-	if special {
-		return equalFoldRight
-	}
-	if nonLetter {
-		return asciiEqualFold
-	}
-	return simpleLetterEqualFold
 }
 
-// equalFoldRight is a specialization of bytes.EqualFold when s is
+func appendFoldedName(out, in []byte) []byte {
-// known to be all ASCII (including punctuation), but contains an 's',
+	for i := 0; i < len(in); {
-// 'S', 'k', or 'K', requiring a Unicode fold on the bytes in t.
+		// Handle single-byte ASCII.
-// See comments on foldFunc.
+		if c := in[i]; c < utf8.RuneSelf {
-func equalFoldRight(s, t []byte) bool {
+			if 'a' <= c && c <= 'z' {
-	for _, sb := range s {
+				c -= 'a' - 'A'
-		if len(t) == 0 {
-			return false
-		}
-		tb := t[0]
-		if tb < utf8.RuneSelf {
-			if sb != tb {
-				sbUpper := sb & caseMask
-				if 'A' <= sbUpper && sbUpper <= 'Z' {
-					if sbUpper != tb&caseMask {
-						return false
-					}
-				} else {
-					return false
-				}
 			}
-			t = t[1:]
+			out = append(out, c)
+			i++
 			continue
 		}
-		// sb is ASCII and t is not. t must be either kelvin
+		// Handle multi-byte Unicode.
-		// sign or long s; sb must be s, S, k, or K.
+		r, n := utf8.DecodeRune(in[i:])
-		tr, size := utf8.DecodeRune(t)
+		out = utf8.AppendRune(out, foldRune(r))
-		switch sb {
+		i += n
-		case 's', 'S':
-			if tr != smallLongEss {
-				return false
-			}
-		case 'k', 'K':
-			if tr != kelvin {
-				return false
-			}
-		default:
-			return false
-		}
-		t = t[size:]
-
 	}
-	if len(t) > 0 {
+	return out
-		return false
-	}
-	return true
 }
 
-// asciiEqualFold is a specialization of bytes.EqualFold for use when
+// foldRune is returns the smallest rune for all runes in the same fold set.
-// s is all ASCII (but may contain non-letters) and contains no
+func foldRune(r rune) rune {
-// special-folding letters.
+	for {
-// See comments on foldFunc.
+		r2 := unicode.SimpleFold(r)
-func asciiEqualFold(s, t []byte) bool {
+		if r2 <= r {
-	if len(s) != len(t) {
+			return r2
-		return false
-	}
-	for i, sb := range s {
-		tb := t[i]
-		if sb == tb {
-			continue
-		}
-		if ('a' <= sb && sb <= 'z') || ('A' <= sb && sb <= 'Z') {
-			if sb&caseMask != tb&caseMask {
-				return false
-			}
-		} else {
-			return false
 		}
+		r = r2
 	}
-	return true
-}
-
-// simpleLetterEqualFold is a specialization of bytes.EqualFold for
-// use when s is all ASCII letters (no underscores, etc) and also
-// doesn't contain 'k', 'K', 's', or 'S'.
-// See comments on foldFunc.
-func simpleLetterEqualFold(s, t []byte) bool {
-	if len(s) != len(t) {
-		return false
-	}
-	for i, b := range s {
-		if b&caseMask != t[i]&caseMask {
-			return false
-		}
-	}
-	return true
 }

gojson/fold_test.go

@@ -6,111 +6,45 @@ package json
 
 import (
 	"bytes"
-	"strings"
 	"testing"
-	"unicode/utf8"
 )
 
-var foldTests = []struct {
+func FuzzEqualFold(f *testing.F) {
-	fn   func(s, t []byte) bool
+	for _, ss := range [][2]string{
-	s, t string
+		{"", ""},
-	want bool
+		{"123abc", "123ABC"},
-}{
+		{"αβδ", "ΑΒΔ"},
-	{equalFoldRight, "", "", true},
+		{"abc", "xyz"},
-	{equalFoldRight, "a", "a", true},
+		{"abc", "XYZ"},
-	{equalFoldRight, "", "a", false},
+		{"1", "2"},
-	{equalFoldRight, "a", "", false},
+		{"hello, world!", "hello, world!"},
-	{equalFoldRight, "a", "A", true},
+		{"hello, world!", "Hello, World!"},
-	{equalFoldRight, "AB", "ab", true},
+		{"hello, world!", "HELLO, WORLD!"},
-	{equalFoldRight, "AB", "ac", false},
+		{"hello, world!", "jello, world!"},
-	{equalFoldRight, "sbkKc", "ſbKKc", true},
+		{"γειά, κόσμε!", "γειά, κόσμε!"},
-	{equalFoldRight, "SbKkc", "ſbKKc", true},
+		{"γειά, κόσμε!", "Γειά, Κόσμε!"},
-	{equalFoldRight, "SbKkc", "ſbKK", false},
+		{"γειά, κόσμε!", "ΓΕΙΆ, ΚΌΣΜΕ!"},
-	{equalFoldRight, "e", "é", false},
+		{"γειά, κόσμε!", "ΛΕΙΆ, ΚΌΣΜΕ!"},
-	{equalFoldRight, "s", "S", true},
+		{"AESKey", "aesKey"},
-
+		{"AESKEY", "aes_key"},
-	{simpleLetterEqualFold, "", "", true},
+		{"aes_key", "AES_KEY"},
-	{simpleLetterEqualFold, "abc", "abc", true},
+		{"AES_KEY", "aes-key"},
-	{simpleLetterEqualFold, "abc", "ABC", true},
+		{"aes-key", "AES-KEY"},
-	{simpleLetterEqualFold, "abc", "ABCD", false},
+		{"AES-KEY", "aesKey"},
-	{simpleLetterEqualFold, "abc", "xxx", false},
+		{"aesKey", "AesKey"},
-
+		{"AesKey", "AESKey"},
-	{asciiEqualFold, "a_B", "A_b", true},
+		{"AESKey", "aeskey"},
-	{asciiEqualFold, "aa@", "aa`", false}, // verify 0x40 and 0x60 aren't case-equivalent
+		{"DESKey", "aeskey"},
-}
+		{"AES Key", "aeskey"},
-
+	} {
-func TestFold(t *testing.T) {
+		f.Add([]byte(ss[0]), []byte(ss[1]))
-	for i, tt := range foldTests {
+	}
-		if got := tt.fn([]byte(tt.s), []byte(tt.t)); got != tt.want {
+	equalFold := func(x, y []byte) bool { return string(foldName(x)) == string(foldName(y)) }
-			t.Errorf("%d. %q, %q = %v; want %v", i, tt.s, tt.t, got, tt.want)
+	f.Fuzz(func(t *testing.T, x, y []byte) {
+		got := equalFold(x, y)
+		want := bytes.EqualFold(x, y)
+		if got != want {
+			t.Errorf("equalFold(%q, %q) = %v, want %v", x, y, got, want)
 		}
-		truth := strings.EqualFold(tt.s, tt.t)
+	})
-		if truth != tt.want {
-			t.Errorf("strings.EqualFold doesn't agree with case %d", i)
-		}
-	}
-}
-
-func TestFoldAgainstUnicode(t *testing.T) {
-	const bufSize = 5
-	buf1 := make([]byte, 0, bufSize)
-	buf2 := make([]byte, 0, bufSize)
-	var runes []rune
-	for i := 0x20; i <= 0x7f; i++ {
-		runes = append(runes, rune(i))
-	}
-	runes = append(runes, kelvin, smallLongEss)
-
-	funcs := []struct {
-		name   string
-		fold   func(s, t []byte) bool
-		letter bool // must be ASCII letter
-		simple bool // must be simple ASCII letter (not 'S' or 'K')
-	}{
-		{
-			name: "equalFoldRight",
-			fold: equalFoldRight,
-		},
-		{
-			name:   "asciiEqualFold",
-			fold:   asciiEqualFold,
-			simple: true,
-		},
-		{
-			name:   "simpleLetterEqualFold",
-			fold:   simpleLetterEqualFold,
-			simple: true,
-			letter: true,
-		},
-	}
-
-	for _, ff := range funcs {
-		for _, r := range runes {
-			if r >= utf8.RuneSelf {
-				continue
-			}
-			if ff.letter && !isASCIILetter(byte(r)) {
-				continue
-			}
-			if ff.simple && (r == 's' || r == 'S' || r == 'k' || r == 'K') {
-				continue
-			}
-			for _, r2 := range runes {
-				buf1 := append(buf1[:0], 'x')
-				buf2 := append(buf2[:0], 'x')
-				buf1 = buf1[:1+utf8.EncodeRune(buf1[1:bufSize], r)]
-				buf2 = buf2[:1+utf8.EncodeRune(buf2[1:bufSize], r2)]
-				buf1 = append(buf1, 'x')
-				buf2 = append(buf2, 'x')
-				want := bytes.EqualFold(buf1, buf2)
-				if got := ff.fold(buf1, buf2); got != want {
-					t.Errorf("%s(%q, %q) = %v; want %v", ff.name, buf1, buf2, got, want)
-				}
-			}
-		}
-	}
-}
-
-func isASCIILetter(b byte) bool {
-	return ('A' <= b && b <= 'Z') || ('a' <= b && b <= 'z')
 }

gojson/fuzz.go

@@ -1,42 +0,0 @@
-// Copyright 2019 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build gofuzz
-
-package json
-
-import (
-	"fmt"
-)
-
-func Fuzz(data []byte) (score int) {
-	for _, ctor := range []func() any{
-		func() any { return new(any) },
-		func() any { return new(map[string]any) },
-		func() any { return new([]any) },
-	} {
-		v := ctor()
-		err := Unmarshal(data, v)
-		if err != nil {
-			continue
-		}
-		score = 1
-
-		m, err := Marshal(v)
-		if err != nil {
-			fmt.Printf("v=%#v\n", v)
-			panic(err)
-		}
-
-		u := ctor()
-		err = Unmarshal(m, u)
-		if err != nil {
-			fmt.Printf("v=%#v\n", v)
-			fmt.Printf("m=%s\n", m)
-			panic(err)
-		}
-	}
-
-	return
-}

gojson/gionic.go

@@ -1,53 +0,0 @@
-package json
-
-import (
-	"net/http"
-)
-
-// Render interface is copied from github.com/gin-gonic/gin@v1.8.1/render/render.go
-type Render interface {
-	// Render writes data with custom ContentType.
-	Render(http.ResponseWriter) error
-	// WriteContentType writes custom ContentType.
-	WriteContentType(w http.ResponseWriter)
-}
-
-type GoJsonRender struct {
-	Data          any
-	NilSafeSlices bool
-	NilSafeMaps   bool
-	Indent        *IndentOpt
-	Filter        *string
-}
-
-func (r GoJsonRender) Render(w http.ResponseWriter) error {
-	header := w.Header()
-	if val := header["Content-Type"]; len(val) == 0 {
-		header["Content-Type"] = []string{"application/json; charset=utf-8"}
-	}
-
-	jsonBytes, err := MarshalSafeCollections(r.Data, r.NilSafeSlices, r.NilSafeMaps, r.Indent, r.Filter)
-	if err != nil {
-		panic(err)
-	}
-	_, err = w.Write(jsonBytes)
-	if err != nil {
-		panic(err)
-	}
-	return nil
-}
-
-func (r GoJsonRender) RenderString() (string, error) {
-	jsonBytes, err := MarshalSafeCollections(r.Data, r.NilSafeSlices, r.NilSafeMaps, r.Indent, r.Filter)
-	if err != nil {
-		panic(err)
-	}
-	return string(jsonBytes), nil
-}
-
-func (r GoJsonRender) WriteContentType(w http.ResponseWriter) {
-	header := w.Header()
-	if val := header["Content-Type"]; len(val) == 0 {
-		header["Content-Type"] = []string{"application/json; charset=utf-8"}
-	}
-}

gojson/indent.go

@@ -4,38 +4,67 @@
 
 package json
 
-import (
+import "bytes"
-	"bytes"
+
-)
+// HTMLEscape appends to dst the JSON-encoded src with <, >, &, U+2028 and U+2029
+// characters inside string literals changed to \u003c, \u003e, \u0026, \u2028, \u2029
+// so that the JSON will be safe to embed inside HTML <script> tags.
+// For historical reasons, web browsers don't honor standard HTML
+// escaping within <script> tags, so an alternative JSON encoding must be used.
+func HTMLEscape(dst *bytes.Buffer, src []byte) {
+	dst.Grow(len(src))
+	dst.Write(appendHTMLEscape(dst.AvailableBuffer(), src))
+}
+
+func appendHTMLEscape(dst, src []byte) []byte {
+	// The characters can only appear in string literals,
+	// so just scan the string one byte at a time.
+	start := 0
+	for i, c := range src {
+		if c == '<' || c == '>' || c == '&' {
+			dst = append(dst, src[start:i]...)
+			dst = append(dst, '\\', 'u', '0', '0', hex[c>>4], hex[c&0xF])
+			start = i + 1
+		}
+		// Convert U+2028 and U+2029 (E2 80 A8 and E2 80 A9).
+		if c == 0xE2 && i+2 < len(src) && src[i+1] == 0x80 && src[i+2]&^1 == 0xA8 {
+			dst = append(dst, src[start:i]...)
+			dst = append(dst, '\\', 'u', '2', '0', '2', hex[src[i+2]&0xF])
+			start = i + len("\u2029")
+		}
+	}
+	return append(dst, src[start:]...)
+}
 
 // Compact appends to dst the JSON-encoded src with
 // insignificant space characters elided.
 func Compact(dst *bytes.Buffer, src []byte) error {
-	return compact(dst, src, false)
+	dst.Grow(len(src))
+	b := dst.AvailableBuffer()
+	b, err := appendCompact(b, src, false)
+	dst.Write(b)
+	return err
 }
 
-func compact(dst *bytes.Buffer, src []byte, escape bool) error {
+func appendCompact(dst, src []byte, escape bool) ([]byte, error) {
-	origLen := dst.Len()
+	origLen := len(dst)
 	scan := newScanner()
 	defer freeScanner(scan)
 	start := 0
 	for i, c := range src {
 		if escape && (c == '<' || c == '>' || c == '&') {
 			if start < i {
-				dst.Write(src[start:i])
+				dst = append(dst, src[start:i]...)
 			}
-			dst.WriteString(`\u00`)
+			dst = append(dst, '\\', 'u', '0', '0', hex[c>>4], hex[c&0xF])
-			dst.WriteByte(hex[c>>4])
-			dst.WriteByte(hex[c&0xF])
 			start = i + 1
 		}
 		// Convert U+2028 and U+2029 (E2 80 A8 and E2 80 A9).
 		if escape && c == 0xE2 && i+2 < len(src) && src[i+1] == 0x80 && src[i+2]&^1 == 0xA8 {
 			if start < i {
-				dst.Write(src[start:i])
+				dst = append(dst, src[start:i]...)
 			}
-			dst.WriteString(`\u202`)
+			dst = append(dst, '\\', 'u', '2', '0', '2', hex[src[i+2]&0xF])
-			dst.WriteByte(hex[src[i+2]&0xF])
 			start = i + 3
 		}
 		v := scan.step(scan, c)
@@ -44,29 +73,37 @@ func compact(dst *bytes.Buffer, src []byte, escape bool) error {
 				break
 			}
 			if start < i {
-				dst.Write(src[start:i])
+				dst = append(dst, src[start:i]...)
 			}
 			start = i + 1
 		}
 	}
 	if scan.eof() == scanError {
-		dst.Truncate(origLen)
+		return dst[:origLen], scan.err
-		return scan.err
 	}
 	if start < len(src) {
-		dst.Write(src[start:])
+		dst = append(dst, src[start:]...)
 	}
-	return nil
+	return dst, nil
 }
 
-func newline(dst *bytes.Buffer, prefix, indent string, depth int) {
+func appendNewline(dst []byte, prefix, indent string, depth int) []byte {
-	dst.WriteByte('\n')
+	dst = append(dst, '\n')
-	dst.WriteString(prefix)
+	dst = append(dst, prefix...)
 	for i := 0; i < depth; i++ {
-		dst.WriteString(indent)
+		dst = append(dst, indent...)
 	}
+	return dst
 }
 
+// indentGrowthFactor specifies the growth factor of indenting JSON input.
+// Empirically, the growth factor was measured to be between 1.4x to 1.8x
+// for some set of compacted JSON with the indent being a single tab.
+// Specify a growth factor slightly larger than what is observed
+// to reduce probability of allocation in appendIndent.
+// A factor no higher than 2 ensures that wasted space never exceeds 50%.
+const indentGrowthFactor = 2
+
 // Indent appends to dst an indented form of the JSON-encoded src.
 // Each element in a JSON object or array begins on a new,
 // indented line beginning with prefix followed by one or more
@@ -79,7 +116,15 @@ func newline(dst *bytes.Buffer, prefix, indent string, depth int) {
 // For example, if src has no trailing spaces, neither will dst;
 // if src ends in a trailing newline, so will dst.
 func Indent(dst *bytes.Buffer, src []byte, prefix, indent string) error {
-	origLen := dst.Len()
+	dst.Grow(indentGrowthFactor * len(src))
+	b := dst.AvailableBuffer()
+	b, err := appendIndent(b, src, prefix, indent)
+	dst.Write(b)
+	return err
+}
+
+func appendIndent(dst, src []byte, prefix, indent string) ([]byte, error) {
+	origLen := len(dst)
 	scan := newScanner()
 	defer freeScanner(scan)
 	needIndent := false
@@ -96,13 +141,13 @@ func Indent(dst *bytes.Buffer, src []byte, prefix, indent string) error {
 		if needIndent && v != scanEndObject && v != scanEndArray {
 			needIndent = false
 			depth++
-			newline(dst, prefix, indent, depth)
+			dst = appendNewline(dst, prefix, indent, depth)
 		}
 
 		// Emit semantically uninteresting bytes
 		// (in particular, punctuation in strings) unmodified.
 		if v == scanContinue {
-			dst.WriteByte(c)
+			dst = append(dst, c)
 			continue
 		}
 
@@ -111,33 +156,27 @@ func Indent(dst *bytes.Buffer, src []byte, prefix, indent string) error {
 		case '{', '[':
 			// delay indent so that empty object and array are formatted as {} and [].
 			needIndent = true
-			dst.WriteByte(c)
+			dst = append(dst, c)
-
 		case ',':
-			dst.WriteByte(c)
+			dst = append(dst, c)
-			newline(dst, prefix, indent, depth)
+			dst = appendNewline(dst, prefix, indent, depth)
-
 		case ':':
-			dst.WriteByte(c)
+			dst = append(dst, c, ' ')
-			dst.WriteByte(' ')
-
 		case '}', ']':
 			if needIndent {
 				// suppress indent in empty object/array
 				needIndent = false
 			} else {
 				depth--
-				newline(dst, prefix, indent, depth)
+				dst = appendNewline(dst, prefix, indent, depth)
 			}
-			dst.WriteByte(c)
+			dst = append(dst, c)
-
 		default:
-			dst.WriteByte(c)
+			dst = append(dst, c)
 		}
 	}
 	if scan.eof() == scanError {
-		dst.Truncate(origLen)
+		return dst[:origLen], scan.err
-		return scan.err
 	}
-	return nil
+	return dst, nil
 }

gojson/number_test.go

@@ -116,18 +116,3 @@ func TestNumberIsValid(t *testing.T) {
 		}
 	}
 }
-
-func BenchmarkNumberIsValid(b *testing.B) {
-	s := "-61657.61667E+61673"
-	for i := 0; i < b.N; i++ {
-		isValidNumber(s)
-	}
-}
-
-func BenchmarkNumberIsValidRegexp(b *testing.B) {
-	var jsonNumberRegexp = regexp.MustCompile(`^-?(?:0|[1-9]\d*)(?:\.\d+)?(?:[eE][+-]?\d+)?$`)
-	s := "-61657.61667E+61673"
-	for i := 0; i < b.N; i++ {
-		jsonNumberRegexp.MatchString(s)
-	}
-}

gojson/scanner.go

@@ -43,7 +43,7 @@ func checkValid(data []byte, scan *scanner) error {
 }
 
 // A SyntaxError is a description of a JSON syntax error.
-// Unmarshal will return a SyntaxError if the JSON can't be parsed.
+// [Unmarshal] will return a SyntaxError if the JSON can't be parsed.
 type SyntaxError struct {
 	msg    string // description of error
 	Offset int64  // error occurred after reading Offset bytes
@@ -594,7 +594,7 @@ func (s *scanner) error(c byte, context string) int {
 	return scanError
 }
 
-// quoteChar formats c as a quoted character literal
+// quoteChar formats c as a quoted character literal.
 func quoteChar(c byte) string {
 	// special cases - different from quoted strings
 	if c == '\'' {

gojson/scanner_test.go

@@ -9,51 +9,59 @@ import (
 	"math"
 	"math/rand"
 	"reflect"
+	"strings"
 	"testing"
 )
 
-var validTests = []struct {
+func indentNewlines(s string) string {
-	data string
+	return strings.Join(strings.Split(s, "\n"), "\n\t")
-	ok   bool
+}
-}{
+
-	{`foo`, false},
+func stripWhitespace(s string) string {
-	{`}{`, false},
+	return strings.Map(func(r rune) rune {
-	{`{]`, false},
+		if r == ' ' || r == '\n' || r == '\r' || r == '\t' {
-	{`{}`, true},
+			return -1
-	{`{"foo":"bar"}`, true},
+		}
-	{`{"foo":"bar","bar":{"baz":["qux"]}}`, true},
+		return r
+	}, s)
 }
 
 func TestValid(t *testing.T) {
-	for _, tt := range validTests {
+	tests := []struct {
-		if ok := Valid([]byte(tt.data)); ok != tt.ok {
+		CaseName
-			t.Errorf("Valid(%#q) = %v, want %v", tt.data, ok, tt.ok)
+		data string
-		}
+		ok   bool
+	}{
+		{Name(""), `foo`, false},
+		{Name(""), `}{`, false},
+		{Name(""), `{]`, false},
+		{Name(""), `{}`, true},
+		{Name(""), `{"foo":"bar"}`, true},
+		{Name(""), `{"foo":"bar","bar":{"baz":["qux"]}}`, true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.Name, func(t *testing.T) {
+			if ok := Valid([]byte(tt.data)); ok != tt.ok {
+				t.Errorf("%s: Valid(`%s`) = %v, want %v", tt.Where, tt.data, ok, tt.ok)
+			}
+		})
 	}
 }
 
-// Tests of simple examples.
+func TestCompactAndIndent(t *testing.T) {
-
+	tests := []struct {
-type example struct {
+		CaseName
-	compact string
+		compact string
-	indent  string
+		indent  string
-}
+	}{
-
+		{Name(""), `1`, `1`},
-var examples = []example{
+		{Name(""), `{}`, `{}`},
-	{`1`, `1`},
+		{Name(""), `[]`, `[]`},
-	{`{}`, `{}`},
+		{Name(""), `{"":2}`, "{\n\t\"\": 2\n}"},
-	{`[]`, `[]`},
+		{Name(""), `[3]`, "[\n\t3\n]"},
-	{`{"":2}`, "{\n\t\"\": 2\n}"},
+		{Name(""), `[1,2,3]`, "[\n\t1,\n\t2,\n\t3\n]"},
-	{`[3]`, "[\n\t3\n]"},
+		{Name(""), `{"x":1}`, "{\n\t\"x\": 1\n}"},
-	{`[1,2,3]`, "[\n\t1,\n\t2,\n\t3\n]"},
+		{Name(""), `[true,false,null,"x",1,1.5,0,-5e+2]`, `[
-	{`{"x":1}`, "{\n\t\"x\": 1\n}"},
-	{ex1, ex1i},
-	{"{\"\":\"<>&\u2028\u2029\"}", "{\n\t\"\": \"<>&\u2028\u2029\"\n}"}, // See golang.org/issue/34070
-}
-
-var ex1 = `[true,false,null,"x",1,1.5,0,-5e+2]`
-
-var ex1i = `[
 	true,
 	false,
 	null,
@@ -62,25 +70,40 @@ var ex1i = `[
 	1.5,
 	0,
 	-5e+2
-]`
+]`},
-
+		{Name(""), "{\"\":\"<>&\u2028\u2029\"}", "{\n\t\"\": \"<>&\u2028\u2029\"\n}"}, // See golang.org/issue/34070
-func TestCompact(t *testing.T) {
+	}
 	var buf bytes.Buffer
-	for _, tt := range examples {
+	for _, tt := range tests {
-		buf.Reset()
+		t.Run(tt.Name, func(t *testing.T) {
-		if err := Compact(&buf, []byte(tt.compact)); err != nil {
+			buf.Reset()
-			t.Errorf("Compact(%#q): %v", tt.compact, err)
+			if err := Compact(&buf, []byte(tt.compact)); err != nil {
-		} else if s := buf.String(); s != tt.compact {
+				t.Errorf("%s: Compact error: %v", tt.Where, err)
-			t.Errorf("Compact(%#q) = %#q, want original", tt.compact, s)
+			} else if got := buf.String(); got != tt.compact {
-		}
+				t.Errorf("%s: Compact:\n\tgot:  %s\n\twant: %s", tt.Where, indentNewlines(got), indentNewlines(tt.compact))
+			}
 
-		buf.Reset()
+			buf.Reset()
-		if err := Compact(&buf, []byte(tt.indent)); err != nil {
+			if err := Compact(&buf, []byte(tt.indent)); err != nil {
-			t.Errorf("Compact(%#q): %v", tt.indent, err)
+				t.Errorf("%s: Compact error: %v", tt.Where, err)
-			continue
+			} else if got := buf.String(); got != tt.compact {
-		} else if s := buf.String(); s != tt.compact {
+				t.Errorf("%s: Compact:\n\tgot:  %s\n\twant: %s", tt.Where, indentNewlines(got), indentNewlines(tt.compact))
-			t.Errorf("Compact(%#q) = %#q, want %#q", tt.indent, s, tt.compact)
+			}
-		}
+
+			buf.Reset()
+			if err := Indent(&buf, []byte(tt.indent), "", "\t"); err != nil {
+				t.Errorf("%s: Indent error: %v", tt.Where, err)
+			} else if got := buf.String(); got != tt.indent {
+				t.Errorf("%s: Compact:\n\tgot:  %s\n\twant: %s", tt.Where, indentNewlines(got), indentNewlines(tt.indent))
+			}
+
+			buf.Reset()
+			if err := Indent(&buf, []byte(tt.compact), "", "\t"); err != nil {
+				t.Errorf("%s: Indent error: %v", tt.Where, err)
+			} else if got := buf.String(); got != tt.indent {
+				t.Errorf("%s: Compact:\n\tgot:  %s\n\twant: %s", tt.Where, indentNewlines(got), indentNewlines(tt.indent))
+			}
+		})
 	}
 }
 
@@ -88,38 +111,21 @@ func TestCompactSeparators(t *testing.T) {
 	// U+2028 and U+2029 should be escaped inside strings.
 	// They should not appear outside strings.
 	tests := []struct {
+		CaseName
 		in, compact string
 	}{
-		{"{\"\u2028\": 1}", "{\"\u2028\":1}"},
+		{Name(""), "{\"\u2028\": 1}", "{\"\u2028\":1}"},
-		{"{\"\u2029\" :2}", "{\"\u2029\":2}"},
+		{Name(""), "{\"\u2029\" :2}", "{\"\u2029\":2}"},
 	}
 	for _, tt := range tests {
-		var buf bytes.Buffer
+		t.Run(tt.Name, func(t *testing.T) {
-		if err := Compact(&buf, []byte(tt.in)); err != nil {
+			var buf bytes.Buffer
-			t.Errorf("Compact(%q): %v", tt.in, err)
+			if err := Compact(&buf, []byte(tt.in)); err != nil {
-		} else if s := buf.String(); s != tt.compact {
+				t.Errorf("%s: Compact error: %v", tt.Where, err)
-			t.Errorf("Compact(%q) = %q, want %q", tt.in, s, tt.compact)
+			} else if got := buf.String(); got != tt.compact {
-		}
+				t.Errorf("%s: Compact:\n\tgot:  %s\n\twant: %s", tt.Where, indentNewlines(got), indentNewlines(tt.compact))
-	}
+			}
-}
+		})
-
-func TestIndent(t *testing.T) {
-	var buf bytes.Buffer
-	for _, tt := range examples {
-		buf.Reset()
-		if err := Indent(&buf, []byte(tt.indent), "", "\t"); err != nil {
-			t.Errorf("Indent(%#q): %v", tt.indent, err)
-		} else if s := buf.String(); s != tt.indent {
-			t.Errorf("Indent(%#q) = %#q, want original", tt.indent, s)
-		}
-
-		buf.Reset()
-		if err := Indent(&buf, []byte(tt.compact), "", "\t"); err != nil {
-			t.Errorf("Indent(%#q): %v", tt.compact, err)
-			continue
-		} else if s := buf.String(); s != tt.indent {
-			t.Errorf("Indent(%#q) = %#q, want %#q", tt.compact, s, tt.indent)
-		}
 	}
 }
 
@@ -129,11 +135,11 @@ func TestCompactBig(t *testing.T) {
 	initBig()
 	var buf bytes.Buffer
 	if err := Compact(&buf, jsonBig); err != nil {
-		t.Fatalf("Compact: %v", err)
+		t.Fatalf("Compact error: %v", err)
 	}
 	b := buf.Bytes()
 	if !bytes.Equal(b, jsonBig) {
-		t.Error("Compact(jsonBig) != jsonBig")
+		t.Error("Compact:")
 		diff(t, b, jsonBig)
 		return
 	}
@@ -144,23 +150,23 @@ func TestIndentBig(t *testing.T) {
 	initBig()
 	var buf bytes.Buffer
 	if err := Indent(&buf, jsonBig, "", "\t"); err != nil {
-		t.Fatalf("Indent1: %v", err)
+		t.Fatalf("Indent error: %v", err)
 	}
 	b := buf.Bytes()
 	if len(b) == len(jsonBig) {
 		// jsonBig is compact (no unnecessary spaces);
 		// indenting should make it bigger
-		t.Fatalf("Indent(jsonBig) did not get bigger")
+		t.Fatalf("Indent did not expand the input")
 	}
 
 	// should be idempotent
 	var buf1 bytes.Buffer
 	if err := Indent(&buf1, b, "", "\t"); err != nil {
-		t.Fatalf("Indent2: %v", err)
+		t.Fatalf("Indent error: %v", err)
 	}
 	b1 := buf1.Bytes()
 	if !bytes.Equal(b1, b) {
-		t.Error("Indent(Indent(jsonBig)) != Indent(jsonBig)")
+		t.Error("Indent(Indent(jsonBig)) != Indent(jsonBig):")
 		diff(t, b1, b)
 		return
 	}
@@ -168,40 +174,40 @@ func TestIndentBig(t *testing.T) {
 	// should get back to original
 	buf1.Reset()
 	if err := Compact(&buf1, b); err != nil {
-		t.Fatalf("Compact: %v", err)
+		t.Fatalf("Compact error: %v", err)
 	}
 	b1 = buf1.Bytes()
 	if !bytes.Equal(b1, jsonBig) {
-		t.Error("Compact(Indent(jsonBig)) != jsonBig")
+		t.Error("Compact(Indent(jsonBig)) != jsonBig:")
 		diff(t, b1, jsonBig)
 		return
 	}
 }
 
-type indentErrorTest struct {
-	in  string
-	err error
-}
-
-var indentErrorTests = []indentErrorTest{
-	{`{"X": "foo", "Y"}`, &SyntaxError{"invalid character '}' after object key", 17}},
-	{`{"X": "foo" "Y": "bar"}`, &SyntaxError{"invalid character '\"' after object key:value pair", 13}},
-}
-
 func TestIndentErrors(t *testing.T) {
-	for i, tt := range indentErrorTests {
+	tests := []struct {
-		slice := make([]uint8, 0)
+		CaseName
-		buf := bytes.NewBuffer(slice)
+		in  string
-		if err := Indent(buf, []uint8(tt.in), "", ""); err != nil {
+		err error
-			if !reflect.DeepEqual(err, tt.err) {
+	}{
-				t.Errorf("#%d: Indent: %#v", i, err)
+		{Name(""), `{"X": "foo", "Y"}`, &SyntaxError{"invalid character '}' after object key", 17}},
-				continue
+		{Name(""), `{"X": "foo" "Y": "bar"}`, &SyntaxError{"invalid character '\"' after object key:value pair", 13}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.Name, func(t *testing.T) {
+			slice := make([]uint8, 0)
+			buf := bytes.NewBuffer(slice)
+			if err := Indent(buf, []uint8(tt.in), "", ""); err != nil {
+				if !reflect.DeepEqual(err, tt.err) {
+					t.Fatalf("%s: Indent error:\n\tgot:  %v\n\twant: %v", tt.Where, err, tt.err)
+				}
 			}
-		}
+		})
 	}
 }
 
 func diff(t *testing.T, a, b []byte) {
+	t.Helper()
 	for i := 0; ; i++ {
 		if i >= len(a) || i >= len(b) || a[i] != b[i] {
 			j := i - 10
@@ -215,10 +221,7 @@ func diff(t *testing.T, a, b []byte) {
 }
 
 func trim(b []byte) []byte {
-	if len(b) > 20 {
+	return b[:min(len(b), 20)]
-		return b[0:20]
-	}
-	return b
 }
 
 // Generate a random JSON object.

gojson/stream.go

@@ -33,7 +33,7 @@ func NewDecoder(r io.Reader) *Decoder {
 }
 
 // UseNumber causes the Decoder to unmarshal a number into an interface{} as a
-// Number instead of as a float64.
+// [Number] instead of as a float64.
 func (dec *Decoder) UseNumber() { dec.d.useNumber = true }
 
 // DisallowUnknownFields causes the Decoder to return an error when the destination
@@ -41,13 +41,10 @@ func (dec *Decoder) UseNumber() { dec.d.useNumber = true }
 // non-ignored, exported fields in the destination.
 func (dec *Decoder) DisallowUnknownFields() { dec.d.disallowUnknownFields = true }
 
-// TagKey sets a different TagKey (instead of "json")
-func (dec *Decoder) TagKey(v string) { dec.d.tagkey = &v }
-
 // Decode reads the next JSON-encoded value from its
 // input and stores it in the value pointed to by v.
 //
-// See the documentation for Unmarshal for details about
+// See the documentation for [Unmarshal] for details about
 // the conversion of JSON into a Go value.
 func (dec *Decoder) Decode(v any) error {
 	if dec.err != nil {
@@ -82,7 +79,7 @@ func (dec *Decoder) Decode(v any) error {
 }
 
 // Buffered returns a reader of the data remaining in the Decoder's
-// buffer. The reader is valid until the next call to Decode.
+// buffer. The reader is valid until the next call to [Decoder.Decode].
 func (dec *Decoder) Buffered() io.Reader {
 	return bytes.NewReader(dec.buf[dec.scanp:])
 }
@@ -186,7 +183,7 @@ type Encoder struct {
 	err        error
 	escapeHTML bool
 
-	indentBuf    *bytes.Buffer
+	indentBuf    []byte
 	indentPrefix string
 	indentValue  string
 }
@@ -197,15 +194,19 @@ func NewEncoder(w io.Writer) *Encoder {
 }
 
 // Encode writes the JSON encoding of v to the stream,
+// with insignificant space characters elided,
 // followed by a newline character.
 //
-// See the documentation for Marshal for details about the
+// See the documentation for [Marshal] for details about the
 // conversion of Go values to JSON.
 func (enc *Encoder) Encode(v any) error {
 	if enc.err != nil {
 		return enc.err
 	}
+
 	e := newEncodeState()
+	defer encodeStatePool.Put(e)
+
 	err := e.marshal(v, encOpts{escapeHTML: enc.escapeHTML})
 	if err != nil {
 		return err
@@ -221,20 +222,15 @@ func (enc *Encoder) Encode(v any) error {
 
 	b := e.Bytes()
 	if enc.indentPrefix != "" || enc.indentValue != "" {
-		if enc.indentBuf == nil {
+		enc.indentBuf, err = appendIndent(enc.indentBuf[:0], b, enc.indentPrefix, enc.indentValue)
-			enc.indentBuf = new(bytes.Buffer)
-		}
-		enc.indentBuf.Reset()
-		err = Indent(enc.indentBuf, b, enc.indentPrefix, enc.indentValue)
 		if err != nil {
 			return err
 		}
-		b = enc.indentBuf.Bytes()
+		b = enc.indentBuf
 	}
 	if _, err = enc.w.Write(b); err != nil {
 		enc.err = err
 	}
-	encodeStatePool.Put(e)
 	return err
 }
 
@@ -258,7 +254,7 @@ func (enc *Encoder) SetEscapeHTML(on bool) {
 }
 
 // RawMessage is a raw encoded JSON value.
-// It implements Marshaler and Unmarshaler and can
+// It implements [Marshaler] and [Unmarshaler] and can
 // be used to delay JSON decoding or precompute a JSON encoding.
 type RawMessage []byte
 
@@ -284,12 +280,12 @@ var _ Unmarshaler = (*RawMessage)(nil)
 
 // A Token holds a value of one of these types:
 //
-//	Delim, for the four JSON delimiters [ ] { }
+//   - [Delim], for the four JSON delimiters [ ] { }
-//	bool, for JSON booleans
+//   - bool, for JSON booleans
-//	float64, for JSON numbers
+//   - float64, for JSON numbers
-//	Number, for JSON numbers
+//   - [Number], for JSON numbers
-//	string, for JSON string literals
+//   - string, for JSON string literals
-//	nil, for JSON null
+//   - nil, for JSON null
 type Token any
 
 const (
@@ -359,14 +355,14 @@ func (d Delim) String() string {
 }
 
 // Token returns the next JSON token in the input stream.
-// At the end of the input stream, Token returns nil, io.EOF.
+// At the end of the input stream, Token returns nil, [io.EOF].
 //
 // Token guarantees that the delimiters [ ] { } it returns are
 // properly nested and matched: if Token encounters an unexpected
 // delimiter in the input, it will return an error.
 //
 // The input stream consists of basic JSON values—bool, string,
-// number, and null—along with delimiters [ ] { } of type Delim
+// number, and null—along with delimiters [ ] { } of type [Delim]
 // to mark the start and end of arrays and objects.
 // Commas and colons are elided.
 func (dec *Decoder) Token() (Token, error) {

gojson/stream_test.go

@@ -6,16 +6,44 @@ package json
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"log"
 	"net"
 	"net/http"
 	"net/http/httptest"
+	"path"
 	"reflect"
+	"runtime"
+	"runtime/debug"
 	"strings"
 	"testing"
 )
 
+// TODO(https://go.dev/issue/52751): Replace with native testing support.
+
+// CaseName is a case name annotated with a file and line.
+type CaseName struct {
+	Name  string
+	Where CasePos
+}
+
+// Name annotates a case name with the file and line of the caller.
+func Name(s string) (c CaseName) {
+	c.Name = s
+	runtime.Callers(2, c.Where.pc[:])
+	return c
+}
+
+// CasePos represents a file and line number.
+type CasePos struct{ pc [1]uintptr }
+
+func (pos CasePos) String() string {
+	frames := runtime.CallersFrames(pos.pc[:])
+	frame, _ := frames.Next()
+	return fmt.Sprintf("%s:%d", path.Base(frame.File), frame.Line)
+}
+
 // Test values for the stream test.
 // One of each JSON kind.
 var streamTest = []any{
@@ -41,24 +69,61 @@ false
 
 func TestEncoder(t *testing.T) {
 	for i := 0; i <= len(streamTest); i++ {
-		var buf bytes.Buffer
+		var buf strings.Builder
 		enc := NewEncoder(&buf)
 		// Check that enc.SetIndent("", "") turns off indentation.
 		enc.SetIndent(">", ".")
 		enc.SetIndent("", "")
 		for j, v := range streamTest[0:i] {
 			if err := enc.Encode(v); err != nil {
-				t.Fatalf("encode #%d: %v", j, err)
+				t.Fatalf("#%d.%d Encode error: %v", i, j, err)
 			}
 		}
 		if have, want := buf.String(), nlines(streamEncoded, i); have != want {
-			t.Errorf("encoding %d items: mismatch", i)
+			t.Errorf("encoding %d items: mismatch:", i)
 			diff(t, []byte(have), []byte(want))
 			break
 		}
 	}
 }
 
+func TestEncoderErrorAndReuseEncodeState(t *testing.T) {
+	// Disable the GC temporarily to prevent encodeState's in Pool being cleaned away during the test.
+	percent := debug.SetGCPercent(-1)
+	defer debug.SetGCPercent(percent)
+
+	// Trigger an error in Marshal with cyclic data.
+	type Dummy struct {
+		Name string
+		Next *Dummy
+	}
+	dummy := Dummy{Name: "Dummy"}
+	dummy.Next = &dummy
+
+	var buf bytes.Buffer
+	enc := NewEncoder(&buf)
+	if err := enc.Encode(dummy); err == nil {
+		t.Errorf("Encode(dummy) error: got nil, want non-nil")
+	}
+
+	type Data struct {
+		A string
+		I int
+	}
+	want := Data{A: "a", I: 1}
+	if err := enc.Encode(want); err != nil {
+		t.Errorf("Marshal error: %v", err)
+	}
+
+	var got Data
+	if err := Unmarshal(buf.Bytes(), &got); err != nil {
+		t.Errorf("Unmarshal error: %v", err)
+	}
+	if got != want {
+		t.Errorf("Marshal/Unmarshal roundtrip:\n\tgot:  %v\n\twant: %v", got, want)
+	}
+}
+
 var streamEncodedIndent = `0.1
 "hello"
 null
@@ -77,14 +142,14 @@ false
 `
 
 func TestEncoderIndent(t *testing.T) {
-	var buf bytes.Buffer
+	var buf strings.Builder
 	enc := NewEncoder(&buf)
 	enc.SetIndent(">", ".")
 	for _, v := range streamTest {
 		enc.Encode(v)
 	}
 	if have, want := buf.String(), streamEncodedIndent; have != want {
-		t.Error("indented encoding mismatch")
+		t.Error("Encode mismatch:")
 		diff(t, []byte(have), []byte(want))
 	}
 }
@@ -122,50 +187,51 @@ func TestEncoderSetEscapeHTML(t *testing.T) {
 		Bar string `json:"bar,string"`
 	}{`<html>foobar</html>`}
 
-	for _, tt := range []struct {
+	tests := []struct {
-		name       string
+		CaseName
 		v          any
 		wantEscape string
 		want       string
 	}{
-		{"c", c, `"\u003c\u0026\u003e"`, `"<&>"`},
+		{Name("c"), c, `"\u003c\u0026\u003e"`, `"<&>"`},
-		{"ct", ct, `"\"\u003c\u0026\u003e\""`, `"\"<&>\""`},
+		{Name("ct"), ct, `"\"\u003c\u0026\u003e\""`, `"\"<&>\""`},
-		{`"<&>"`, "<&>", `"\u003c\u0026\u003e"`, `"<&>"`},
+		{Name(`"<&>"`), "<&>", `"\u003c\u0026\u003e"`, `"<&>"`},
 		{
-			"tagStruct", tagStruct,
+			Name("tagStruct"), tagStruct,
 			`{"\u003c\u003e\u0026#! ":0,"Invalid":0}`,
 			`{"<>&#! ":0,"Invalid":0}`,
 		},
 		{
-			`"<str>"`, marshalerStruct,
+			Name(`"<str>"`), marshalerStruct,
 			`{"NonPtr":"\u003cstr\u003e","Ptr":"\u003cstr\u003e"}`,
 			`{"NonPtr":"<str>","Ptr":"<str>"}`,
 		},
 		{
-			"stringOption", stringOption,
+			Name("stringOption"), stringOption,
 			`{"bar":"\"\\u003chtml\\u003efoobar\\u003c/html\\u003e\""}`,
 			`{"bar":"\"<html>foobar</html>\""}`,
 		},
-	} {
+	}
-		var buf bytes.Buffer
+	for _, tt := range tests {
-		enc := NewEncoder(&buf)
+		t.Run(tt.Name, func(t *testing.T) {
-		if err := enc.Encode(tt.v); err != nil {
+			var buf strings.Builder
-			t.Errorf("Encode(%s): %s", tt.name, err)
+			enc := NewEncoder(&buf)
-			continue
+			if err := enc.Encode(tt.v); err != nil {
-		}
+				t.Fatalf("%s: Encode(%s) error: %s", tt.Where, tt.Name, err)
-		if got := strings.TrimSpace(buf.String()); got != tt.wantEscape {
+			}
-			t.Errorf("Encode(%s) = %#q, want %#q", tt.name, got, tt.wantEscape)
+			if got := strings.TrimSpace(buf.String()); got != tt.wantEscape {
-		}
+				t.Errorf("%s: Encode(%s):\n\tgot:  %s\n\twant: %s", tt.Where, tt.Name, got, tt.wantEscape)
-		buf.Reset()
+			}
-		enc.SetEscapeHTML(false)
+			buf.Reset()
-		if err := enc.Encode(tt.v); err != nil {
+			enc.SetEscapeHTML(false)
-			t.Errorf("SetEscapeHTML(false) Encode(%s): %s", tt.name, err)
+			if err := enc.Encode(tt.v); err != nil {
-			continue
+				t.Fatalf("%s: SetEscapeHTML(false) Encode(%s) error: %s", tt.Where, tt.Name, err)
-		}
+			}
-		if got := strings.TrimSpace(buf.String()); got != tt.want {
+			if got := strings.TrimSpace(buf.String()); got != tt.want {
-			t.Errorf("SetEscapeHTML(false) Encode(%s) = %#q, want %#q",
+				t.Errorf("%s: SetEscapeHTML(false) Encode(%s):\n\tgot:  %s\n\twant: %s",
-				tt.name, got, tt.want)
+					tt.Where, tt.Name, got, tt.want)
-		}
+			}
+		})
 	}
 }
 
@@ -186,14 +252,14 @@ func TestDecoder(t *testing.T) {
 		dec := NewDecoder(&buf)
 		for j := range out {
 			if err := dec.Decode(&out[j]); err != nil {
-				t.Fatalf("decode #%d/%d: %v", j, i, err)
+				t.Fatalf("decode #%d/%d error: %v", j, i, err)
 			}
 		}
 		if !reflect.DeepEqual(out, streamTest[0:i]) {
-			t.Errorf("decoding %d items: mismatch", i)
+			t.Errorf("decoding %d items: mismatch:", i)
 			for j := range out {
 				if !reflect.DeepEqual(out[j], streamTest[j]) {
-					t.Errorf("#%d: have %v want %v", j, out[j], streamTest[j])
+					t.Errorf("#%d:\n\tgot:  %v\n\twant: %v", j, out[j], streamTest[j])
 				}
 			}
 			break
@@ -212,14 +278,14 @@ func TestDecoderBuffered(t *testing.T) {
 		t.Fatal(err)
 	}
 	if m.Name != "Gopher" {
-		t.Errorf("Name = %q; want Gopher", m.Name)
+		t.Errorf("Name = %s, want Gopher", m.Name)
 	}
 	rest, err := io.ReadAll(d.Buffered())
 	if err != nil {
 		t.Fatal(err)
 	}
-	if g, w := string(rest), " extra "; g != w {
+	if got, want := string(rest), " extra "; got != want {
-		t.Errorf("Remaining = %q; want %q", g, w)
+		t.Errorf("Remaining = %s, want %s", got, want)
 	}
 }
 
@@ -244,20 +310,20 @@ func TestRawMessage(t *testing.T) {
 		Y  float32
 	}
 	const raw = `["\u0056",null]`
-	const msg = `{"X":0.1,"Id":["\u0056",null],"Y":0.2}`
+	const want = `{"X":0.1,"Id":["\u0056",null],"Y":0.2}`
-	err := Unmarshal([]byte(msg), &data)
+	err := Unmarshal([]byte(want), &data)
 	if err != nil {
-		t.Fatalf("Unmarshal: %v", err)
+		t.Fatalf("Unmarshal error: %v", err)
 	}
 	if string([]byte(data.Id)) != raw {
-		t.Fatalf("Raw mismatch: have %#q want %#q", []byte(data.Id), raw)
+		t.Fatalf("Unmarshal:\n\tgot:  %s\n\twant: %s", []byte(data.Id), raw)
 	}
-	b, err := Marshal(&data)
+	got, err := Marshal(&data)
 	if err != nil {
-		t.Fatalf("Marshal: %v", err)
+		t.Fatalf("Marshal error: %v", err)
 	}
-	if string(b) != msg {
+	if string(got) != want {
-		t.Fatalf("Marshal: have %#q want %#q", b, msg)
+		t.Fatalf("Marshal:\n\tgot:  %s\n\twant: %s", got, want)
 	}
 }
 
@@ -268,174 +334,156 @@ func TestNullRawMessage(t *testing.T) {
 		IdPtr *RawMessage
 		Y     float32
 	}
-	const msg = `{"X":0.1,"Id":null,"IdPtr":null,"Y":0.2}`
+	const want = `{"X":0.1,"Id":null,"IdPtr":null,"Y":0.2}`
-	err := Unmarshal([]byte(msg), &data)
+	err := Unmarshal([]byte(want), &data)
 	if err != nil {
-		t.Fatalf("Unmarshal: %v", err)
+		t.Fatalf("Unmarshal error: %v", err)
 	}
 	if want, got := "null", string(data.Id); want != got {
-		t.Fatalf("Raw mismatch: have %q, want %q", got, want)
+		t.Fatalf("Unmarshal:\n\tgot:  %s\n\twant: %s", got, want)
 	}
 	if data.IdPtr != nil {
-		t.Fatalf("Raw pointer mismatch: have non-nil, want nil")
+		t.Fatalf("pointer mismatch: got non-nil, want nil")
 	}
-	b, err := Marshal(&data)
+	got, err := Marshal(&data)
 	if err != nil {
-		t.Fatalf("Marshal: %v", err)
+		t.Fatalf("Marshal error: %v", err)
 	}
-	if string(b) != msg {
+	if string(got) != want {
-		t.Fatalf("Marshal: have %#q want %#q", b, msg)
+		t.Fatalf("Marshal:\n\tgot:  %s\n\twant: %s", got, want)
 	}
 }
 
-var blockingTests = []string{
-	`{"x": 1}`,
-	`[1, 2, 3]`,
-}
-
 func TestBlocking(t *testing.T) {
-	for _, enc := range blockingTests {
+	tests := []struct {
-		r, w := net.Pipe()
+		CaseName
-		go w.Write([]byte(enc))
+		in string
-		var val any
+	}{
-
+		{Name(""), `{"x": 1}`},
-		// If Decode reads beyond what w.Write writes above,
+		{Name(""), `[1, 2, 3]`},
-		// it will block, and the test will deadlock.
-		if err := NewDecoder(r).Decode(&val); err != nil {
-			t.Errorf("decoding %s: %v", enc, err)
-		}
-		r.Close()
-		w.Close()
 	}
-}
+	for _, tt := range tests {
+		t.Run(tt.Name, func(t *testing.T) {
+			r, w := net.Pipe()
+			go w.Write([]byte(tt.in))
+			var val any
 
-func BenchmarkEncoderEncode(b *testing.B) {
+			// If Decode reads beyond what w.Write writes above,
-	b.ReportAllocs()
+			// it will block, and the test will deadlock.
-	type T struct {
+			if err := NewDecoder(r).Decode(&val); err != nil {
-		X, Y string
+				t.Errorf("%s: NewDecoder(%s).Decode error: %v", tt.Where, tt.in, err)
-	}
-	v := &T{"foo", "bar"}
-	b.RunParallel(func(pb *testing.PB) {
-		for pb.Next() {
-			if err := NewEncoder(io.Discard).Encode(v); err != nil {
-				b.Fatal(err)
 			}
-		}
+			r.Close()
-	})
+			w.Close()
-}
+		})
-
+	}
-type tokenStreamCase struct {
-	json      string
-	expTokens []any
 }
 
 type decodeThis struct {
 	v any
 }
 
-var tokenStreamCases = []tokenStreamCase{
-	// streaming token cases
-	{json: `10`, expTokens: []any{float64(10)}},
-	{json: ` [10] `, expTokens: []any{
-		Delim('['), float64(10), Delim(']')}},
-	{json: ` [false,10,"b"] `, expTokens: []any{
-		Delim('['), false, float64(10), "b", Delim(']')}},
-	{json: `{ "a": 1 }`, expTokens: []any{
-		Delim('{'), "a", float64(1), Delim('}')}},
-	{json: `{"a": 1, "b":"3"}`, expTokens: []any{
-		Delim('{'), "a", float64(1), "b", "3", Delim('}')}},
-	{json: ` [{"a": 1},{"a": 2}] `, expTokens: []any{
-		Delim('['),
-		Delim('{'), "a", float64(1), Delim('}'),
-		Delim('{'), "a", float64(2), Delim('}'),
-		Delim(']')}},
-	{json: `{"obj": {"a": 1}}`, expTokens: []any{
-		Delim('{'), "obj", Delim('{'), "a", float64(1), Delim('}'),
-		Delim('}')}},
-	{json: `{"obj": [{"a": 1}]}`, expTokens: []any{
-		Delim('{'), "obj", Delim('['),
-		Delim('{'), "a", float64(1), Delim('}'),
-		Delim(']'), Delim('}')}},
-
-	// streaming tokens with intermittent Decode()
-	{json: `{ "a": 1 }`, expTokens: []any{
-		Delim('{'), "a",
-		decodeThis{float64(1)},
-		Delim('}')}},
-	{json: ` [ { "a" : 1 } ] `, expTokens: []any{
-		Delim('['),
-		decodeThis{map[string]any{"a": float64(1)}},
-		Delim(']')}},
-	{json: ` [{"a": 1},{"a": 2}] `, expTokens: []any{
-		Delim('['),
-		decodeThis{map[string]any{"a": float64(1)}},
-		decodeThis{map[string]any{"a": float64(2)}},
-		Delim(']')}},
-	{json: `{ "obj" : [ { "a" : 1 } ] }`, expTokens: []any{
-		Delim('{'), "obj", Delim('['),
-		decodeThis{map[string]any{"a": float64(1)}},
-		Delim(']'), Delim('}')}},
-
-	{json: `{"obj": {"a": 1}}`, expTokens: []any{
-		Delim('{'), "obj",
-		decodeThis{map[string]any{"a": float64(1)}},
-		Delim('}')}},
-	{json: `{"obj": [{"a": 1}]}`, expTokens: []any{
-		Delim('{'), "obj",
-		decodeThis{[]any{
-			map[string]any{"a": float64(1)},
-		}},
-		Delim('}')}},
-	{json: ` [{"a": 1} {"a": 2}] `, expTokens: []any{
-		Delim('['),
-		decodeThis{map[string]any{"a": float64(1)}},
-		decodeThis{&SyntaxError{"expected comma after array element", 11}},
-	}},
-	{json: `{ "` + strings.Repeat("a", 513) + `" 1 }`, expTokens: []any{
-		Delim('{'), strings.Repeat("a", 513),
-		decodeThis{&SyntaxError{"expected colon after object key", 518}},
-	}},
-	{json: `{ "\a" }`, expTokens: []any{
-		Delim('{'),
-		&SyntaxError{"invalid character 'a' in string escape code", 3},
-	}},
-	{json: ` \a`, expTokens: []any{
-		&SyntaxError{"invalid character '\\\\' looking for beginning of value", 1},
-	}},
-}
-
 func TestDecodeInStream(t *testing.T) {
-	for ci, tcase := range tokenStreamCases {
+	tests := []struct {
+		CaseName
+		json      string
+		expTokens []any
+	}{
+		// streaming token cases
+		{CaseName: Name(""), json: `10`, expTokens: []any{float64(10)}},
+		{CaseName: Name(""), json: ` [10] `, expTokens: []any{
+			Delim('['), float64(10), Delim(']')}},
+		{CaseName: Name(""), json: ` [false,10,"b"] `, expTokens: []any{
+			Delim('['), false, float64(10), "b", Delim(']')}},
+		{CaseName: Name(""), json: `{ "a": 1 }`, expTokens: []any{
+			Delim('{'), "a", float64(1), Delim('}')}},
+		{CaseName: Name(""), json: `{"a": 1, "b":"3"}`, expTokens: []any{
+			Delim('{'), "a", float64(1), "b", "3", Delim('}')}},
+		{CaseName: Name(""), json: ` [{"a": 1},{"a": 2}] `, expTokens: []any{
+			Delim('['),
+			Delim('{'), "a", float64(1), Delim('}'),
+			Delim('{'), "a", float64(2), Delim('}'),
+			Delim(']')}},
+		{CaseName: Name(""), json: `{"obj": {"a": 1}}`, expTokens: []any{
+			Delim('{'), "obj", Delim('{'), "a", float64(1), Delim('}'),
+			Delim('}')}},
+		{CaseName: Name(""), json: `{"obj": [{"a": 1}]}`, expTokens: []any{
+			Delim('{'), "obj", Delim('['),
+			Delim('{'), "a", float64(1), Delim('}'),
+			Delim(']'), Delim('}')}},
 
-		dec := NewDecoder(strings.NewReader(tcase.json))
+		// streaming tokens with intermittent Decode()
-		for i, etk := range tcase.expTokens {
+		{CaseName: Name(""), json: `{ "a": 1 }`, expTokens: []any{
+			Delim('{'), "a",
+			decodeThis{float64(1)},
+			Delim('}')}},
+		{CaseName: Name(""), json: ` [ { "a" : 1 } ] `, expTokens: []any{
+			Delim('['),
+			decodeThis{map[string]any{"a": float64(1)}},
+			Delim(']')}},
+		{CaseName: Name(""), json: ` [{"a": 1},{"a": 2}] `, expTokens: []any{
+			Delim('['),
+			decodeThis{map[string]any{"a": float64(1)}},
+			decodeThis{map[string]any{"a": float64(2)}},
+			Delim(']')}},
+		{CaseName: Name(""), json: `{ "obj" : [ { "a" : 1 } ] }`, expTokens: []any{
+			Delim('{'), "obj", Delim('['),
+			decodeThis{map[string]any{"a": float64(1)}},
+			Delim(']'), Delim('}')}},
 
-			var tk any
+		{CaseName: Name(""), json: `{"obj": {"a": 1}}`, expTokens: []any{
-			var err error
+			Delim('{'), "obj",
+			decodeThis{map[string]any{"a": float64(1)}},
+			Delim('}')}},
+		{CaseName: Name(""), json: `{"obj": [{"a": 1}]}`, expTokens: []any{
+			Delim('{'), "obj",
+			decodeThis{[]any{
+				map[string]any{"a": float64(1)},
+			}},
+			Delim('}')}},
+		{CaseName: Name(""), json: ` [{"a": 1} {"a": 2}] `, expTokens: []any{
+			Delim('['),
+			decodeThis{map[string]any{"a": float64(1)}},
+			decodeThis{&SyntaxError{"expected comma after array element", 11}},
+		}},
+		{CaseName: Name(""), json: `{ "` + strings.Repeat("a", 513) + `" 1 }`, expTokens: []any{
+			Delim('{'), strings.Repeat("a", 513),
+			decodeThis{&SyntaxError{"expected colon after object key", 518}},
+		}},
+		{CaseName: Name(""), json: `{ "\a" }`, expTokens: []any{
+			Delim('{'),
+			&SyntaxError{"invalid character 'a' in string escape code", 3},
+		}},
+		{CaseName: Name(""), json: ` \a`, expTokens: []any{
+			&SyntaxError{"invalid character '\\\\' looking for beginning of value", 1},
+		}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.Name, func(t *testing.T) {
+			dec := NewDecoder(strings.NewReader(tt.json))
+			for i, want := range tt.expTokens {
+				var got any
+				var err error
 
-			if dt, ok := etk.(decodeThis); ok {
+				if dt, ok := want.(decodeThis); ok {
-				etk = dt.v
+					want = dt.v
-				err = dec.Decode(&tk)
+					err = dec.Decode(&got)
-			} else {
+				} else {
-				tk, err = dec.Token()
+					got, err = dec.Token()
-			}
+				}
-			if experr, ok := etk.(error); ok {
+				if errWant, ok := want.(error); ok {
-				if err == nil || !reflect.DeepEqual(err, experr) {
+					if err == nil || !reflect.DeepEqual(err, errWant) {
-					t.Errorf("case %v: Expected error %#v in %q, but was %#v", ci, experr, tcase.json, err)
+						t.Fatalf("%s:\n\tinput: %s\n\tgot error:  %v\n\twant error: %v", tt.Where, tt.json, err, errWant)
+					}
+					break
+				} else if err != nil {
+					t.Fatalf("%s:\n\tinput: %s\n\tgot error:  %v\n\twant error: nil", tt.Where, tt.json, err)
+				}
+				if !reflect.DeepEqual(got, want) {
+					t.Fatalf("%s: token %d:\n\tinput: %s\n\tgot:  %T(%v)\n\twant: %T(%v)", tt.Where, i, tt.json, got, got, want, want)
 				}
-				break
-			} else if err == io.EOF {
-				t.Errorf("case %v: Unexpected EOF in %q", ci, tcase.json)
-				break
-			} else if err != nil {
-				t.Errorf("case %v: Unexpected error '%#v' in %q", ci, err, tcase.json)
-				break
 			}
-			if !reflect.DeepEqual(tk, etk) {
+		})
-				t.Errorf(`case %v: %q @ %v expected %T(%v) was %T(%v)`, ci, tcase.json, i, etk, etk, tk, tk)
-				break
-			}
-		}
 	}
 }
 
@@ -449,7 +497,7 @@ func TestHTTPDecoding(t *testing.T) {
 	defer ts.Close()
 	res, err := http.Get(ts.URL)
 	if err != nil {
-		log.Fatalf("GET failed: %v", err)
+		log.Fatalf("http.Get error: %v", err)
 	}
 	defer res.Body.Close()
 
@@ -460,15 +508,15 @@ func TestHTTPDecoding(t *testing.T) {
 	d := NewDecoder(res.Body)
 	err = d.Decode(&foo)
 	if err != nil {
-		t.Fatalf("Decode: %v", err)
+		t.Fatalf("Decode error: %v", err)
 	}
 	if foo.Foo != "bar" {
-		t.Errorf("decoded %q; want \"bar\"", foo.Foo)
+		t.Errorf(`Decode: got %q, want "bar"`, foo.Foo)
 	}
 
 	// make sure we get the EOF the second time
 	err = d.Decode(&foo)
 	if err != io.EOF {
-		t.Errorf("err = %v; want io.EOF", err)
+		t.Errorf("Decode error:\n\tgot:  %v\n\twant: io.EOF", err)
 	}
 }

gojson/tagkey_test.go

@@ -72,49 +72,50 @@ type unicodeTag struct {
 	W string `json:"Ελλάδα"`
 }
 
-var structTagObjectKeyTests = []struct {
-	raw   any
-	value string
-	key   string
-}{
-	{basicLatin2xTag{"2x"}, "2x", "$%-/"},
-	{basicLatin3xTag{"3x"}, "3x", "0123456789"},
-	{basicLatin4xTag{"4x"}, "4x", "ABCDEFGHIJKLMO"},
-	{basicLatin5xTag{"5x"}, "5x", "PQRSTUVWXYZ_"},
-	{basicLatin6xTag{"6x"}, "6x", "abcdefghijklmno"},
-	{basicLatin7xTag{"7x"}, "7x", "pqrstuvwxyz"},
-	{miscPlaneTag{"いろはにほへと"}, "いろはにほへと", "色は匂へど"},
-	{dashTag{"foo"}, "foo", "-"},
-	{emptyTag{"Pour Moi"}, "Pour Moi", "W"},
-	{misnamedTag{"Animal Kingdom"}, "Animal Kingdom", "X"},
-	{badFormatTag{"Orfevre"}, "Orfevre", "Y"},
-	{badCodeTag{"Reliable Man"}, "Reliable Man", "Z"},
-	{percentSlashTag{"brut"}, "brut", "text/html%"},
-	{punctuationTag{"Union Rags"}, "Union Rags", "!#$%&()*+-./:;<=>?@[]^_{|}~ "},
-	{spaceTag{"Perreddu"}, "Perreddu", "With space"},
-	{unicodeTag{"Loukanikos"}, "Loukanikos", "Ελλάδα"},
-}
-
 func TestStructTagObjectKey(t *testing.T) {
-	for _, tt := range structTagObjectKeyTests {
+	tests := []struct {
-		b, err := Marshal(tt.raw)
+		CaseName
-		if err != nil {
+		raw   any
-			t.Fatalf("Marshal(%#q) failed: %v", tt.raw, err)
+		value string
-		}
+		key   string
-		var f any
+	}{
-		err = Unmarshal(b, &f)
+		{Name(""), basicLatin2xTag{"2x"}, "2x", "$%-/"},
-		if err != nil {
+		{Name(""), basicLatin3xTag{"3x"}, "3x", "0123456789"},
-			t.Fatalf("Unmarshal(%#q) failed: %v", b, err)
+		{Name(""), basicLatin4xTag{"4x"}, "4x", "ABCDEFGHIJKLMO"},
-		}
+		{Name(""), basicLatin5xTag{"5x"}, "5x", "PQRSTUVWXYZ_"},
-		for i, v := range f.(map[string]any) {
+		{Name(""), basicLatin6xTag{"6x"}, "6x", "abcdefghijklmno"},
-			switch i {
+		{Name(""), basicLatin7xTag{"7x"}, "7x", "pqrstuvwxyz"},
-			case tt.key:
+		{Name(""), miscPlaneTag{"いろはにほへと"}, "いろはにほへと", "色は匂へど"},
-				if s, ok := v.(string); !ok || s != tt.value {
+		{Name(""), dashTag{"foo"}, "foo", "-"},
-					t.Fatalf("Unexpected value: %#q, want %v", s, tt.value)
+		{Name(""), emptyTag{"Pour Moi"}, "Pour Moi", "W"},
-				}
+		{Name(""), misnamedTag{"Animal Kingdom"}, "Animal Kingdom", "X"},
-			default:
+		{Name(""), badFormatTag{"Orfevre"}, "Orfevre", "Y"},
-				t.Fatalf("Unexpected key: %#q, from %#q", i, b)
+		{Name(""), badCodeTag{"Reliable Man"}, "Reliable Man", "Z"},
+		{Name(""), percentSlashTag{"brut"}, "brut", "text/html%"},
+		{Name(""), punctuationTag{"Union Rags"}, "Union Rags", "!#$%&()*+-./:;<=>?@[]^_{|}~ "},
+		{Name(""), spaceTag{"Perreddu"}, "Perreddu", "With space"},
+		{Name(""), unicodeTag{"Loukanikos"}, "Loukanikos", "Ελλάδα"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.Name, func(t *testing.T) {
+			b, err := Marshal(tt.raw)
+			if err != nil {
+				t.Fatalf("%s: Marshal error: %v", tt.Where, err)
 			}
-		}
+			var f any
+			err = Unmarshal(b, &f)
+			if err != nil {
+				t.Fatalf("%s: Unmarshal error: %v", tt.Where, err)
+			}
+			for k, v := range f.(map[string]any) {
+				if k == tt.key {
+					if s, ok := v.(string); !ok || s != tt.value {
+						t.Fatalf("%s: Unmarshal(%#q) value:\n\tgot:  %q\n\twant: %q", tt.Where, b, s, tt.value)
+					}
+				} else {
+					t.Fatalf("%s: Unmarshal(%#q): unexpected key: %q", tt.Where, b, k)
+				}
+			}
+		})
 	}
 }

gojson/tags_test.go

@@ -22,7 +22,7 @@ func TestTagParsing(t *testing.T) {
 		{"bar", false},
 	} {
 		if opts.Contains(tt.opt) != tt.want {
-			t.Errorf("Contains(%q) = %v", tt.opt, !tt.want)
+			t.Errorf("Contains(%q) = %v, want %v", tt.opt, !tt.want, tt.want)
 		}
 	}
 }