perf: Optimize Stringify allocations (~3x faster) (#3914)

Author: merchantmoh-debug

github/strings.go

@@ -9,17 +9,30 @@ import (
 	"bytes"
 	"fmt"
 	"reflect"
+	"strconv"
+	"sync"
 )
 
 var timestampType = reflect.TypeFor[Timestamp]()
 
+var bufferPool = sync.Pool{
+	New: func() any {
+		return new(bytes.Buffer)
+	},
+}
+
 // Stringify attempts to create a reasonable string representation of types in
 // the GitHub library. It does things like resolve pointers to their values
 // and omits struct fields with nil values.
 func Stringify(message any) string {
-	var buf bytes.Buffer
+	buf := bufferPool.Get().(*bytes.Buffer)
+	defer func() {
+		buf.Reset()
+		bufferPool.Put(buf)
+	}()
+
 	v := reflect.ValueOf(message)
-	stringifyValue(&buf, v)
+	stringifyValue(buf, v)
 	return buf.String()
 }
 
@@ -34,8 +47,20 @@ func stringifyValue(w *bytes.Buffer, val reflect.Value) {
 	v := reflect.Indirect(val)
 
 	switch v.Kind() {
+	case reflect.Bool:
+		w.Write(strconv.AppendBool(w.Bytes(), v.Bool())[w.Len():])
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		w.Write(strconv.AppendInt(w.Bytes(), v.Int(), 10)[w.Len():])
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		w.Write(strconv.AppendUint(w.Bytes(), v.Uint(), 10)[w.Len():])
+	case reflect.Float32:
+		w.Write(strconv.AppendFloat(w.Bytes(), v.Float(), 'g', -1, 32)[w.Len():])
+	case reflect.Float64:
+		w.Write(strconv.AppendFloat(w.Bytes(), v.Float(), 'g', -1, 64)[w.Len():])
 	case reflect.String:
-		fmt.Fprintf(w, `"%v"`, v)
+		w.WriteByte('"')
+		w.WriteString(v.String())
+		w.WriteByte('"')
 	case reflect.Slice:
 		w.WriteByte('[')
 		for i := range v.Len() {

github/strings_benchmark_test.go

@@ -0,0 +1,37 @@
+// Copyright 2026 The go-github AUTHORS. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package github
+
+import (
+	"testing"
+)
+
+type BenchmarkStruct struct {
+	Name    string
+	Age     int
+	Active  bool
+	Score   float32
+	Rank    float64
+	Tags    []string
+	Pointer *int
+}
+
+func BenchmarkStringify(b *testing.B) {
+	val := 42
+	s := &BenchmarkStruct{
+		Name:    "benchmark",
+		Age:     30,
+		Active:  true,
+		Score:   1.1,
+		Rank:    99.999999,
+		Tags:    []string{"go", "github", "api"},
+		Pointer: Ptr(val),
+	}
+	b.ResetTimer()
+	for b.Loop() {
+		Stringify(s)
+	}
+}

github/strings_test.go

@@ -81,6 +81,92 @@ func TestStringify(t *testing.T) {
 	}
 }
 
+func TestStringify_Primitives(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		in  any
+		out string
+	}{
+		// Bool
+		{true, "true"},
+		{false, "false"},
+
+		// Int variants
+		{int(1), "1"},
+		{int8(2), "2"},
+		{int16(3), "3"},
+		{int32(4), "4"},
+		{int64(5), "5"},
+
+		// Uint variants
+		{uint(6), "6"},
+		{uint8(7), "7"},
+		{uint16(8), "8"},
+		{uint32(9), "9"},
+		{uint64(10), "10"},
+		{uintptr(11), "11"},
+
+		// Float variants (Precision Correctness)
+		{float32(1.1), "1.1"},
+		{float64(1.1), "1.1"},
+		{float32(1.0000001), "1.0000001"},
+		{float64(1.000000000000001), "1.000000000000001"},
+
+		// Boundary Cases
+		{int8(-128), "-128"},
+		{int8(127), "127"},
+		{uint64(18446744073709551615), "18446744073709551615"},
+
+		// String Optimization
+		{"hello", `"hello"`},
+		{"", `""`},
+	}
+
+	for i, tt := range tests {
+		s := Stringify(tt.in)
+		if s != tt.out {
+			t.Errorf("%v. Stringify(%T) => %q, want %q", i, tt.in, s, tt.out)
+		}
+	}
+}
+
+func TestStringify_BufferPool(t *testing.T) {
+	t.Parallel()
+	// Verify that concurrent usage of Stringify is safe and doesn't corrupt buffers.
+	// While we can't easily verify reuse without exposing internal metrics,
+	// we can verify correctness under load which implies proper Reset() handling.
+	const goroutines = 10
+	const iterations = 100
+
+	errCh := make(chan error, goroutines)
+
+	for range goroutines {
+		go func() {
+			for range iterations {
+				// Use a mix of types to exercise different code paths
+				s1 := Stringify(123)
+				if s1 != "123" {
+					errCh <- fmt.Errorf("got %q, want %q", s1, "123")
+					return
+				}
+
+				s2 := Stringify("test")
+				if s2 != `"test"` {
+					errCh <- fmt.Errorf("got %q, want %q", s2, `"test"`)
+					return
+				}
+			}
+			errCh <- nil
+		}()
+	}
+
+	for range goroutines {
+		if err := <-errCh; err != nil {
+			t.Error(err)
+		}
+	}
+}
+
 // Directly test the String() methods on various GitHub types. We don't do an
 // exhaustive test of all the various field types, since TestStringify() above
 // takes care of that. Rather, we just make sure that Stringify() is being
@@ -143,3 +229,23 @@ func TestString(t *testing.T) {
 		}
 	}
 }
+
+func TestStringify_Floats(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		in  any
+		out string
+	}{
+		{float32(1.1), "1.1"},
+		{float64(1.1), "1.1"},
+		{float32(1.0000001), "1.0000001"},
+		{struct{ F float32 }{1.1}, "{F:1.1}"},
+	}
+
+	for i, tt := range tests {
+		s := Stringify(tt.in)
+		if s != tt.out {
+			t.Errorf("%v. Stringify(%v) = %q, want %q", i, tt.in, s, tt.out)
+		}
+	}
+}