3e8ca36823
Determine if a slice contains unique items by hashing them. This should take linear time on average, better than the previous quadratic algorithm. Change-Id: I8dc95bb6f29d802bdbc64bc7f7e698c71eae5ce7 Reviewed-on: https://go-review.googlesource.com/c/tools/+/669455 Reviewed-by: Alan Donovan <adonovan@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
498 lines
16 KiB
Go
498 lines
16 KiB
Go
// Copyright 2025 The Go MCP SDK Authors. All rights reserved.
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// Use of this source code is governed by an MIT-style
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// license that can be found in the LICENSE file.
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package jsonschema
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import (
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"fmt"
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"hash/maphash"
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"math"
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"math/big"
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"reflect"
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"regexp"
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"slices"
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"strings"
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"unicode/utf8"
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)
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// The value of the "$schema" keyword for the version that we can validate.
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const draft202012 = "https://json-schema.org/draft/2020-12/schema"
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// Temporary definition of ResolvedSchema.
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// The full definition deals with references between schemas, specifically the $id, $anchor and $ref keywords.
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// We'll ignore that for now.
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type ResolvedSchema struct {
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root *Schema
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}
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// Validate validates the instance, which must be a JSON value, against the schema.
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// It returns nil if validation is successful or an error if it is not.
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func (rs *ResolvedSchema) Validate(instance any) error {
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if s := rs.root.Schema; s != "" && s != draft202012 {
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return fmt.Errorf("cannot validate version %s, only %s", s, draft202012)
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}
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st := &state{rs: rs}
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var pathBuffer [4]any
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return st.validate(reflect.ValueOf(instance), st.rs.root, nil, pathBuffer[:0])
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}
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// state is the state of single call to ResolvedSchema.Validate.
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type state struct {
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rs *ResolvedSchema
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depth int
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}
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// validate validates the reflected value of the instance.
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// It keeps track of the path within the instance for better error messages.
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func (st *state) validate(instance reflect.Value, schema *Schema, callerAnns *annotations, path []any) (err error) {
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defer func() {
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if err != nil {
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if p := formatPath(path); p != "" {
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err = fmt.Errorf("%s: %w", p, err)
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}
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}
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}()
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st.depth++
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defer func() { st.depth-- }()
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if st.depth >= 100 {
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return fmt.Errorf("max recursion depth of %d reached", st.depth)
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}
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// Treat the nil schema like the empty schema, as accepting everything.
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if schema == nil {
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return nil
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}
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// Step through interfaces.
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if instance.IsValid() && instance.Kind() == reflect.Interface {
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instance = instance.Elem()
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}
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// type: https://json-schema.org/draft/2020-12/draft-bhutton-json-schema-validation-01#section-6.1.1
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if schema.Type != "" || schema.Types != nil {
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gotType, ok := jsonType(instance)
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if !ok {
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return fmt.Errorf("%v of type %[1]T is not a valid JSON value", instance)
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}
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if schema.Type != "" {
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// "number" subsumes integers
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if !(gotType == schema.Type ||
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gotType == "integer" && schema.Type == "number") {
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return fmt.Errorf("type: %v has type %q, want %q", instance, gotType, schema.Type)
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}
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} else {
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if !(slices.Contains(schema.Types, gotType) || (gotType == "integer" && slices.Contains(schema.Types, "number"))) {
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return fmt.Errorf("type: %v has type %q, want one of %q",
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instance, gotType, strings.Join(schema.Types, ", "))
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}
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}
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}
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// enum: https://json-schema.org/draft/2020-12/draft-bhutton-json-schema-validation-01#section-6.1.2
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if schema.Enum != nil {
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ok := false
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for _, e := range schema.Enum {
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if equalValue(reflect.ValueOf(e), instance) {
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ok = true
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break
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}
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}
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if !ok {
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return fmt.Errorf("enum: %v does not equal any of: %v", instance, schema.Enum)
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}
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}
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// const: https://json-schema.org/draft/2020-12/draft-bhutton-json-schema-validation-01#section-6.1.3
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if schema.Const != nil {
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if !equalValue(reflect.ValueOf(*schema.Const), instance) {
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return fmt.Errorf("const: %v does not equal %v", instance, *schema.Const)
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}
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}
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// numbers: https://json-schema.org/draft/2020-12/draft-bhutton-json-schema-validation-01#section-6.2
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if schema.MultipleOf != nil || schema.Minimum != nil || schema.Maximum != nil || schema.ExclusiveMinimum != nil || schema.ExclusiveMaximum != nil {
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n, ok := jsonNumber(instance)
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if ok { // these keywords don't apply to non-numbers
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if schema.MultipleOf != nil {
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// TODO: validate MultipleOf as non-zero.
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// The test suite assumes floats.
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nf, _ := n.Float64() // don't care if it's exact or not
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if _, f := math.Modf(nf / *schema.MultipleOf); f != 0 {
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return fmt.Errorf("multipleOf: %s is not a multiple of %f", n, *schema.MultipleOf)
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}
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}
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m := new(big.Rat) // reuse for all of the following
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cmp := func(f float64) int { return n.Cmp(m.SetFloat64(f)) }
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if schema.Minimum != nil && cmp(*schema.Minimum) < 0 {
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return fmt.Errorf("minimum: %s is less than %f", n, *schema.Minimum)
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}
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if schema.Maximum != nil && cmp(*schema.Maximum) > 0 {
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return fmt.Errorf("maximum: %s is greater than %f", n, *schema.Maximum)
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}
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if schema.ExclusiveMinimum != nil && cmp(*schema.ExclusiveMinimum) <= 0 {
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return fmt.Errorf("exclusiveMinimum: %s is less than or equal to %f", n, *schema.ExclusiveMinimum)
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}
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if schema.ExclusiveMaximum != nil && cmp(*schema.ExclusiveMaximum) >= 0 {
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return fmt.Errorf("exclusiveMaximum: %s is greater than or equal to %f", n, *schema.ExclusiveMaximum)
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}
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}
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}
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// strings: https://json-schema.org/draft/2020-12/draft-bhutton-json-schema-validation-01#section-6.3
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if instance.Kind() == reflect.String && (schema.MinLength != nil || schema.MaxLength != nil || schema.Pattern != "") {
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str := instance.String()
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n := utf8.RuneCountInString(str)
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if schema.MinLength != nil {
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if m := *schema.MinLength; n < m {
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return fmt.Errorf("minLength: %q contains %d Unicode code points, fewer than %d", str, n, m)
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}
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}
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if schema.MaxLength != nil {
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if m := *schema.MaxLength; n > m {
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return fmt.Errorf("maxLength: %q contains %d Unicode code points, more than %d", str, n, m)
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}
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}
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if schema.Pattern != "" {
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// TODO(jba): compile regexps during schema validation.
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m, err := regexp.MatchString(schema.Pattern, str)
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if err != nil {
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return err
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}
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if !m {
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return fmt.Errorf("pattern: %q does not match pattern %q", str, schema.Pattern)
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}
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}
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}
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// logic
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// https://json-schema.org/draft/2020-12/json-schema-core#section-10.2
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// These must happen before arrays and objects because if they evaluate an item or property,
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// then the unevaluatedItems/Properties schemas don't apply to it.
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// See https://json-schema.org/draft/2020-12/json-schema-core#section-11.2, paragraph 4.
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//
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// If any of these fail, then validation fails, even if there is an unevaluatedXXX
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// keyword in the schema. The spec is unclear about this, but that is the intention.
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var anns annotations // all the annotations for this call and child calls
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valid := func(s *Schema, anns *annotations) bool { return st.validate(instance, s, anns, path) == nil }
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if schema.AllOf != nil {
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for _, ss := range schema.AllOf {
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if err := st.validate(instance, ss, &anns, path); err != nil {
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return err
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}
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}
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}
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if schema.AnyOf != nil {
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// We must visit them all, to collect annotations.
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ok := false
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for _, ss := range schema.AnyOf {
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if valid(ss, &anns) {
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ok = true
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}
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}
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if !ok {
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return fmt.Errorf("anyOf: did not validate against any of %v", schema.AnyOf)
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}
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}
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if schema.OneOf != nil {
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// Exactly one.
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var okSchema *Schema
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for _, ss := range schema.OneOf {
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if valid(ss, &anns) {
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if okSchema != nil {
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return fmt.Errorf("oneOf: validated against both %v and %v", okSchema, ss)
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}
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okSchema = ss
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}
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}
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if okSchema == nil {
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return fmt.Errorf("oneOf: did not validate against any of %v", schema.OneOf)
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}
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}
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if schema.Not != nil {
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// Ignore annotations from "not".
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if valid(schema.Not, nil) {
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return fmt.Errorf("not: validated against %v", schema.Not)
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}
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}
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if schema.If != nil {
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var ss *Schema
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if valid(schema.If, &anns) {
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ss = schema.Then
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} else {
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ss = schema.Else
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}
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if ss != nil {
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if err := st.validate(instance, ss, &anns, path); err != nil {
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return err
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}
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}
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}
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// arrays
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if instance.Kind() == reflect.Array || instance.Kind() == reflect.Slice {
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// https://json-schema.org/draft/2020-12/json-schema-core#section-10.3.1
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// This validate call doesn't collect annotations for the items of the instance; they are separate
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// instances in their own right.
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// TODO(jba): if the test suite doesn't cover this case, add a test. For example, nested arrays.
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for i, ischema := range schema.PrefixItems {
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if i >= instance.Len() {
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break // shorter is OK
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}
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if err := st.validate(instance.Index(i), ischema, nil, append(path, i)); err != nil {
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return err
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}
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}
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anns.noteEndIndex(min(len(schema.PrefixItems), instance.Len()))
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if schema.Items != nil {
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for i := len(schema.PrefixItems); i < instance.Len(); i++ {
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if err := st.validate(instance.Index(i), schema.Items, nil, append(path, i)); err != nil {
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return err
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}
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}
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// Note that all the items in this array have been validated.
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anns.allItems = true
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}
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nContains := 0
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if schema.Contains != nil {
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for i := range instance.Len() {
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if err := st.validate(instance.Index(i), schema.Contains, nil, append(path, i)); err == nil {
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nContains++
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anns.noteIndex(i)
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}
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}
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if nContains == 0 && (schema.MinContains == nil || *schema.MinContains > 0) {
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return fmt.Errorf("contains: %s does not have an item matching %s",
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instance, schema.Contains)
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}
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}
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// https://json-schema.org/draft/2020-12/draft-bhutton-json-schema-validation-01#section-6.4
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// TODO(jba): check that these next four keywords' values are integers.
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if schema.MinContains != nil && schema.Contains != nil {
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if m := *schema.MinContains; nContains < m {
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return fmt.Errorf("minContains: contains validated %d items, less than %d", nContains, m)
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}
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}
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if schema.MaxContains != nil && schema.Contains != nil {
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if m := *schema.MaxContains; nContains > m {
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return fmt.Errorf("maxContains: contains validated %d items, greater than %d", nContains, m)
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}
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}
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if schema.MinItems != nil {
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if m := *schema.MinItems; instance.Len() < m {
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return fmt.Errorf("minItems: array length %d is less than %d", instance.Len(), m)
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}
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}
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if schema.MaxItems != nil {
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if m := *schema.MaxItems; instance.Len() > m {
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return fmt.Errorf("maxItems: array length %d is greater than %d", instance.Len(), m)
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}
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}
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if schema.UniqueItems {
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if instance.Len() > 1 {
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// Hash each item and compare the hashes.
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// If two hashes differ, the items differ.
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// If two hashes are the same, compare the collisions for equality.
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// (The same logic as hash table lookup.)
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// TODO(jba): Use container/hash.Map when it becomes available (https://go.dev/issue/69559),
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hashes := map[uint64][]int{} // from hash to indices
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seed := maphash.MakeSeed()
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for i := range instance.Len() {
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item := instance.Index(i)
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var h maphash.Hash
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h.SetSeed(seed)
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hashValue(&h, item)
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hv := h.Sum64()
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if sames := hashes[hv]; len(sames) > 0 {
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for _, j := range sames {
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if equalValue(item, instance.Index(j)) {
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return fmt.Errorf("uniqueItems: array items %d and %d are equal", i, j)
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}
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}
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}
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hashes[hv] = append(hashes[hv], i)
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}
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}
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}
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// https://json-schema.org/draft/2020-12/json-schema-core#section-11.2
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if schema.UnevaluatedItems != nil && !anns.allItems {
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// Apply this subschema to all items in the array that haven't been successfully validated.
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// That includes validations by subschemas on the same instance, like allOf.
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for i := anns.endIndex; i < instance.Len(); i++ {
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if !anns.evaluatedIndexes[i] {
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if err := st.validate(instance.Index(i), schema.UnevaluatedItems, nil, append(path, i)); err != nil {
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return err
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}
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}
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}
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anns.allItems = true
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}
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}
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// objects
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// https://json-schema.org/draft/2020-12/json-schema-core#section-10.3.2
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if instance.Kind() == reflect.Map {
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if kt := instance.Type().Key(); kt.Kind() != reflect.String {
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return fmt.Errorf("map key type %s is not a string", kt)
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}
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// Track the evaluated properties for just this schema, to support additionalProperties.
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// If we used anns here, then we'd be including properties evaluated in subschemas
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// from allOf, etc., which additionalProperties shouldn't observe.
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evalProps := map[string]bool{}
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for prop, schema := range schema.Properties {
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val := instance.MapIndex(reflect.ValueOf(prop))
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if !val.IsValid() {
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// It's OK if the instance doesn't have the property.
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continue
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}
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if err := st.validate(val, schema, nil, append(path, prop)); err != nil {
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return err
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}
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evalProps[prop] = true
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}
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if len(schema.PatternProperties) > 0 {
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for vprop, val := range instance.Seq2() {
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prop := vprop.String()
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// Check every matching pattern.
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for pattern, schema := range schema.PatternProperties {
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// TODO(jba): pre-compile regexps
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m, err := regexp.MatchString(pattern, prop)
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if err != nil {
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return err
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}
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if m {
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if err := st.validate(val, schema, nil, append(path, prop)); err != nil {
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return err
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}
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evalProps[prop] = true
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}
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}
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}
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}
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if schema.AdditionalProperties != nil {
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// Apply to all properties not handled above.
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for vprop, val := range instance.Seq2() {
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prop := vprop.String()
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if !evalProps[prop] {
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if err := st.validate(val, schema.AdditionalProperties, nil, append(path, prop)); err != nil {
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return err
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}
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evalProps[prop] = true
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}
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}
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}
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anns.noteProperties(evalProps)
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if schema.PropertyNames != nil {
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for prop := range instance.Seq() {
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if err := st.validate(prop, schema.PropertyNames, nil, append(path, prop.String())); err != nil {
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return err
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}
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}
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}
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// https://json-schema.org/draft/2020-12/draft-bhutton-json-schema-validation-01#section-6.5
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if schema.MinProperties != nil {
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if n, m := instance.Len(), *schema.MinProperties; n < m {
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return fmt.Errorf("minProperties: object has %d properties, less than %d", n, m)
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}
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}
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if schema.MaxProperties != nil {
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if n, m := instance.Len(), *schema.MaxProperties; n > m {
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return fmt.Errorf("maxProperties: object has %d properties, greater than %d", n, m)
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}
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}
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hasProperty := func(prop string) bool {
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return instance.MapIndex(reflect.ValueOf(prop)).IsValid()
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}
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missingProperties := func(props []string) []string {
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var missing []string
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for _, p := range props {
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if !hasProperty(p) {
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missing = append(missing, p)
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}
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}
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return missing
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}
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if schema.Required != nil {
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if m := missingProperties(schema.Required); len(m) > 0 {
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return fmt.Errorf("required: missing properties: %q", m)
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}
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}
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if schema.DependentRequired != nil {
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// "Validation succeeds if, for each name that appears in both the instance
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// and as a name within this keyword's value, every item in the corresponding
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// array is also the name of a property in the instance." §6.5.4
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for dprop, reqs := range schema.DependentRequired {
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if hasProperty(dprop) {
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if m := missingProperties(reqs); len(m) > 0 {
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return fmt.Errorf("dependentRequired[%q]: missing properties %q", dprop, m)
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}
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}
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}
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}
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// https://json-schema.org/draft/2020-12/json-schema-core#section-10.2.2.4
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if schema.DependentSchemas != nil {
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// This does not collect annotations, although it seems like it should.
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for dprop, ss := range schema.DependentSchemas {
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if hasProperty(dprop) {
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// TODO: include dependentSchemas[dprop] in the errors.
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err := st.validate(instance, ss, &anns, path)
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if err != nil {
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return err
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}
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}
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}
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}
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if schema.UnevaluatedProperties != nil && !anns.allProperties {
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// This looks a lot like AdditionalProperties, but depends on in-place keywords like allOf
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// in addition to sibling keywords.
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for vprop, val := range instance.Seq2() {
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prop := vprop.String()
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if !anns.evaluatedProperties[prop] {
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if err := st.validate(val, schema.UnevaluatedProperties, nil, append(path, prop)); err != nil {
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return err
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}
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}
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}
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// The spec says the annotation should be the set of evaluated properties, but we can optimize
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// by setting a single boolean, since after this succeeds all properties will be validated.
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// See https://json-schema.slack.com/archives/CT7FF623C/p1745592564381459.
|
|
anns.allProperties = true
|
|
}
|
|
}
|
|
|
|
if callerAnns != nil {
|
|
// Our caller wants to know what we've validated.
|
|
callerAnns.merge(&anns)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func formatPath(path []any) string {
|
|
var b strings.Builder
|
|
for i, p := range path {
|
|
if n, ok := p.(int); ok {
|
|
fmt.Fprintf(&b, "[%d]", n)
|
|
} else {
|
|
if i > 0 {
|
|
b.WriteByte('.')
|
|
}
|
|
fmt.Fprintf(&b, "%q", p)
|
|
}
|
|
}
|
|
return b.String()
|
|
}
|