Address backend implementation review findings

This commit is contained in:
2026-07-29 19:08:05 +00:00
parent 359b7313f4
commit f89cb94ed2
17 changed files with 203 additions and 1036 deletions

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@@ -0,0 +1,232 @@
// Package jsonvalue validates and defensively copies JSON-compatible value
// trees used by public configuration and request boundaries.
package jsonvalue
import (
"encoding/json"
"fmt"
"math"
"reflect"
"sort"
"strconv"
)
const maxSafeJSONInteger = 1<<53 - 1
type visit struct {
typ reflect.Type
ptr uintptr
}
// CopyMap validates and deeply copies an extra-parameter map while preserving
// compatible concrete map, slice, array, scalar, and number types.
func CopyMap(src map[string]any) (map[string]any, error) {
if src == nil {
return nil, nil
}
copied, err := copyValue(reflect.ValueOf(src), "extra_params", make(map[visit]struct{}))
if err != nil {
return nil, err
}
out, ok := copied.(map[string]any)
if !ok {
return nil, fmt.Errorf("extra_params: expected object")
}
return out, nil
}
func copyValue(value reflect.Value, path string, seen map[visit]struct{}) (any, error) {
if !value.IsValid() {
return nil, nil
}
if value.Kind() == reflect.Interface {
if value.IsNil() {
return nil, nil
}
return copyValue(value.Elem(), path, seen)
}
if !value.CanInterface() {
return nil, fmt.Errorf("%s: value cannot be copied", path)
}
if number, ok := value.Interface().(json.Number); ok {
if _, err := json.Marshal(number); err != nil {
return nil, fmt.Errorf("%s: invalid JSON number", path)
}
f, err := strconv.ParseFloat(number.String(), 64)
if err != nil || math.IsNaN(f) || math.IsInf(f, 0) {
return nil, fmt.Errorf("%s: invalid JSON number", path)
}
return number, nil
}
switch value.Kind() {
case reflect.Bool, reflect.String:
return value.Interface(), nil
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
if value.Int() < -maxSafeJSONInteger || value.Int() > maxSafeJSONInteger {
return nil, fmt.Errorf("%s: integer is outside the JSON-safe range", path)
}
return value.Interface(), nil
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
if value.Uint() > maxSafeJSONInteger {
return nil, fmt.Errorf("%s: integer is outside the JSON-safe range", path)
}
return value.Interface(), nil
case reflect.Float32, reflect.Float64:
number := value.Convert(reflect.TypeOf(float64(0))).Float()
if math.IsNaN(number) || math.IsInf(number, 0) {
return nil, fmt.Errorf("%s: floating-point value must be finite", path)
}
return value.Interface(), nil
case reflect.Pointer:
if value.IsNil() {
return nil, nil
}
current := visit{typ: value.Type(), ptr: value.Pointer()}
if _, ok := seen[current]; ok {
return nil, fmt.Errorf("%s: cyclic value is not supported", path)
}
seen[current] = struct{}{}
defer delete(seen, current)
return copyValue(value.Elem(), path, seen)
case reflect.Map:
return copyMapValue(value, path, seen)
case reflect.Slice:
if value.IsNil() {
return nil, nil
}
return copySequenceValue(value, path, seen)
case reflect.Array:
return copySequenceValue(value, path, seen)
default:
return nil, fmt.Errorf("%s: unsupported JSON value type %s", path, value.Type())
}
}
func copyMapValue(value reflect.Value, path string, seen map[visit]struct{}) (any, error) {
if value.IsNil() {
return nil, nil
}
if value.Type().Key().Kind() != reflect.String {
return nil, fmt.Errorf("%s: map key type %s is not supported", path, value.Type().Key())
}
current := visit{typ: value.Type(), ptr: value.Pointer()}
if _, ok := seen[current]; ok {
return nil, fmt.Errorf("%s: cyclic value is not supported", path)
}
seen[current] = struct{}{}
defer delete(seen, current)
keys := value.MapKeys()
sort.Slice(keys, func(i, j int) bool {
return keys[i].String() < keys[j].String()
})
type entry struct {
key reflect.Value
name string
value any
}
entries := make([]entry, 0, len(keys))
preserveType := true
elementType := value.Type().Elem()
for _, key := range keys {
name := key.String()
if name == "" {
return nil, fmt.Errorf("%s: map key must not be empty", path)
}
copied, err := copyValue(value.MapIndex(key), path+"."+name, seen)
if err != nil {
return nil, err
}
entries = append(entries, entry{key: key, name: name, value: copied})
if copied == nil {
if !canAssignNil(elementType) {
preserveType = false
}
continue
}
if !reflect.TypeOf(copied).AssignableTo(elementType) {
preserveType = false
}
}
if preserveType {
out := reflect.MakeMapWithSize(value.Type(), len(entries))
for _, entry := range entries {
if entry.value == nil {
out.SetMapIndex(entry.key, reflect.Zero(elementType))
continue
}
out.SetMapIndex(entry.key, reflect.ValueOf(entry.value))
}
return out.Interface(), nil
}
out := make(map[string]any, len(entries))
for _, entry := range entries {
out[entry.name] = entry.value
}
return out, nil
}
func copySequenceValue(value reflect.Value, path string, seen map[visit]struct{}) (any, error) {
var current visit
if value.Kind() == reflect.Slice {
current = visit{typ: value.Type(), ptr: value.Pointer()}
if _, ok := seen[current]; ok {
return nil, fmt.Errorf("%s: cyclic value is not supported", path)
}
seen[current] = struct{}{}
defer delete(seen, current)
}
values := make([]any, value.Len())
preserveType := true
elementType := value.Type().Elem()
for i := 0; i < value.Len(); i++ {
copied, err := copyValue(value.Index(i), fmt.Sprintf("%s[%d]", path, i), seen)
if err != nil {
return nil, err
}
values[i] = copied
if copied == nil {
if !canAssignNil(elementType) {
preserveType = false
}
continue
}
if !reflect.TypeOf(copied).AssignableTo(elementType) {
preserveType = false
}
}
if preserveType {
out := reflect.New(value.Type()).Elem()
if value.Kind() == reflect.Slice {
out = reflect.MakeSlice(value.Type(), value.Len(), value.Len())
}
for i, copied := range values {
if copied == nil {
out.Index(i).Set(reflect.Zero(elementType))
continue
}
out.Index(i).Set(reflect.ValueOf(copied))
}
return out.Interface(), nil
}
out := make([]any, len(values))
copy(out, values)
return out, nil
}
func canAssignNil(typ reflect.Type) bool {
switch typ.Kind() {
case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Pointer, reflect.Slice:
return true
default:
return false
}
}

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@@ -0,0 +1,97 @@
package jsonvalue_test
import (
"encoding/json"
"math"
"reflect"
"testing"
"gitea.maximumdirect.net/eric/promptkit/internal/jsonvalue"
)
func TestCopyMapPreservesTypesAndIsolatesMutations(t *testing.T) {
nested := map[string]int{"limit": 2}
sequence := []string{"one", "two"}
input := map[string]any{
"count": int64(7),
"number": json.Number("-1.25e+2"),
"nested": nested,
"sequence": sequence,
}
copied, err := jsonvalue.CopyMap(input)
if err != nil {
t.Fatalf("copy map: %v", err)
}
nested["limit"] = 99
sequence[0] = "changed"
input["added"] = true
if got, ok := copied["count"].(int64); !ok || got != 7 {
t.Fatalf("integer type or value changed: %#v", copied["count"])
}
if got, ok := copied["number"].(json.Number); !ok || got != "-1.25e+2" {
t.Fatalf("JSON number type or value changed: %#v", copied["number"])
}
if got := copied["nested"].(map[string]int)["limit"]; got != 2 {
t.Fatalf("nested map was not isolated: %d", got)
}
if got := copied["sequence"].([]string)[0]; got != "one" {
t.Fatalf("sequence was not isolated: %q", got)
}
if _, ok := copied["added"]; ok {
t.Fatalf("top-level map was not isolated: %#v", copied)
}
}
func TestCopyMapRejectsInvalidValues(t *testing.T) {
cyclicMap := map[string]any{}
cyclicMap["self"] = cyclicMap
cyclicSlice := []any{nil}
cyclicSlice[0] = cyclicSlice
tests := []struct {
name string
value any
}{
{name: "empty nested key", value: map[string]int{"": 1}},
{name: "non-string map key", value: map[int]string{1: "one"}},
{name: "unsupported value", value: make(chan int)},
{name: "cyclic map", value: cyclicMap},
{name: "cyclic slice", value: cyclicSlice},
{name: "NaN", value: math.NaN()},
{name: "positive infinity", value: math.Inf(1)},
{name: "unsafe signed integer", value: int64(1 << 53)},
{name: "unsafe unsigned integer", value: uint64(1 << 53)},
}
for _, tc := range tests {
t.Run(tc.name, func(t *testing.T) {
if _, err := jsonvalue.CopyMap(map[string]any{"value": tc.value}); err == nil {
t.Fatal("expected validation error")
}
})
}
}
func TestCopyMapValidatesJSONNumberSyntaxAndRange(t *testing.T) {
for _, number := range []json.Number{"0", "-1", "1.25", "-1.25e+2"} {
t.Run("valid "+number.String(), func(t *testing.T) {
got, err := jsonvalue.CopyMap(map[string]any{"value": number})
if err != nil {
t.Fatalf("copy valid JSON number: %v", err)
}
if !reflect.DeepEqual(got["value"], number) {
t.Fatalf("JSON number changed: got %#v want %#v", got["value"], number)
}
})
}
for _, number := range []json.Number{"", "01", "+1", "1.", ".1", "1e9999", "not-a-number"} {
t.Run("invalid "+number.String(), func(t *testing.T) {
if _, err := jsonvalue.CopyMap(map[string]any{"value": number}); err == nil {
t.Fatal("expected invalid JSON number error")
}
})
}
}