From 04b9783485fb124fd77c8946b612d94ec9cc617e Mon Sep 17 00:00:00 2001
From: Joe Betz <jpbetz@google.com>
Date: Fri, 6 Dec 2024 21:00:25 -0500
Subject: [PATCH] Ignore unknown k8s:validation comments tags

---
 pkg/generators/markers.go      | 35 ++++++++++++++++++++++++++++++++--
 pkg/generators/markers_test.go | 18 +++++++++++++++++
 pkg/generators/openapi_test.go |  3 ++-
 3 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/pkg/generators/markers.go b/pkg/generators/markers.go
index c4dd67d3b..a8af60b6c 100644
--- a/pkg/generators/markers.go
+++ b/pkg/generators/markers.go
@@ -20,9 +20,11 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"reflect"
 	"regexp"
 	"strconv"
 	"strings"
+	"sync"
 
 	"k8s.io/gengo/v2/types"
 	openapi "k8s.io/kube-openapi/pkg/common"
@@ -61,6 +63,34 @@ func (c *CELTag) Validate() error {
 	return nil
 }
 
+// isKnownTagCommentKey returns true if the given key is a known comment tag key.
+// Known keys are identified by the json field tags in the commentTags struct.
+// If the key is a composite key, only the first key part is checked, and is
+// expected to be separated by the remainder of the key by a ':' or '[' delimiter.
+func isKnownTagCommentKey(key string) bool {
+	split := func(r rune) bool { return r == ':' || r == '[' }
+	commentTags := strings.FieldsFunc(key, split)
+	if len(commentTags) == 0 {
+		return false
+	}
+	_, ok := tagKeys()[commentTags[0]]
+	return ok
+}
+
+var tagKeys = sync.OnceValue(func() map[string]struct{} {
+	result := map[string]struct{}{}
+	t := reflect.TypeOf(commentTags{})
+	for i := 0; i < t.NumField(); i++ {
+		field := t.Field(i)
+		if jsonTag := field.Tag.Get("json"); jsonTag != "" {
+			if key, _, _ := strings.Cut(jsonTag, ","); key != "" {
+				result[key] = struct{}{}
+			}
+		}
+	}
+	return result
+})
+
 // commentTags represents the parsed comment tags for a given type. These types are then used to generate schema validations.
 // These only include the newer prefixed tags. The older tags are still supported,
 // but are not included in this struct. Comment Tags are transformed into a
@@ -385,12 +415,11 @@ func memberWithJSONName(t *types.Type, key string) *types.Member {
 	return nil
 }
 
-// Parses the given comments into a CommentTags type. Validates the parsed comment tags, and returns the result.
+// ParseCommentTags parses the given comments into a CommentTags type. Validates the parsed comment tags, and returns the result.
 // Accepts an optional type to validate against, and a prefix to filter out markers not related to validation.
 // Accepts a prefix to filter out markers not related to validation.
 // Returns any errors encountered while parsing or validating the comment tags.
 func ParseCommentTags(t *types.Type, comments []string, prefix string) (*spec.Schema, error) {
-
 	markers, err := parseMarkers(comments, prefix)
 	if err != nil {
 		return nil, fmt.Errorf("failed to parse marker comments: %w", err)
@@ -610,6 +639,8 @@ func parseMarkers(markerComments []string, prefix string) (map[string]any, error
 
 		if len(key) == 0 {
 			return nil, fmt.Errorf("cannot have empty key for marker comment")
+		} else if !isKnownTagCommentKey(key) {
+			continue
 		} else if _, ok := parseSymbolReference(value, ""); ok {
 			// Skip ref markers
 			continue
diff --git a/pkg/generators/markers_test.go b/pkg/generators/markers_test.go
index 28f6e551a..6377fc57d 100644
--- a/pkg/generators/markers_test.go
+++ b/pkg/generators/markers_test.go
@@ -19,6 +19,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
+
 	"k8s.io/gengo/v2/types"
 	"k8s.io/kube-openapi/pkg/generators"
 	"k8s.io/kube-openapi/pkg/validation/spec"
@@ -960,6 +961,23 @@ func TestCommentTags_Validate(t *testing.T) {
 			},
 			errorMessage: `failed to validate property "name": pattern can only be used on string types`,
 		},
+		{
+			name: "ignore unknown field with unparsable value",
+			comments: []string{
+				`+k8s:validation:xyz=a=b`, // a=b is not a valid value
+			},
+			t: &types.Type{
+				Kind: types.Struct,
+				Name: types.Name{Name: "struct"},
+				Members: []types.Member{
+					{
+						Name: "name",
+						Type: types.String,
+						Tags: `json:"name"`,
+					},
+				},
+			},
+		},
 	}
 
 	for _, tc := range testCases {
diff --git a/pkg/generators/openapi_test.go b/pkg/generators/openapi_test.go
index e53292129..55be4c557 100644
--- a/pkg/generators/openapi_test.go
+++ b/pkg/generators/openapi_test.go
@@ -27,6 +27,7 @@ import (
 	"github.com/google/go-cmp/cmp"
 	"golang.org/x/tools/go/packages"
 	"golang.org/x/tools/go/packages/packagestest"
+
 	"k8s.io/gengo/v2/generator"
 	"k8s.io/gengo/v2/namer"
 	"k8s.io/gengo/v2/parser"
@@ -2386,7 +2387,7 @@ func TestMarkerComments(t *testing.T) {
 			// +k8s:validation:pattern="^foo$[0-9]+"
 			StringValue string
 
-			// +k8s:validation:maxitems=10
+			// +k8s:validation:maxItems=10
 			// +k8s:validation:minItems=1
 			// +k8s:validation:uniqueItems
 			ArrayValue []string