Address comment

staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/schema/cel/validation.go

@@ -325,19 +325,17 @@ func unescapeSingleQuote(s string) (string, error) {
 // ValidFieldPath validates that jsonPath is a valid JSON Path containing only field and map accessors
 // that are valid for the given schema, and returns a field.Path representation of the validated jsonPath or an error.
 func ValidFieldPath(jsonPath string, schema *schema.Structural) (validFieldPath *field.Path, err error) {
-	appendToPath := func(name string) error {
-		if schema.AdditionalProperties != nil {
+	appendToPath := func(name string, isNamed bool) error {
+		if !isNamed {
 			validFieldPath = validFieldPath.Key(name)
 			schema = schema.AdditionalProperties.Structural
-		} else if schema.Properties != nil {
+		} else {
 			validFieldPath = validFieldPath.Child(name)
 			val, ok := schema.Properties[name]
 			if !ok {
 				return fmt.Errorf("does not refer to a valid field")
 			}
 			schema = &val
-		} else {
-			return fmt.Errorf("does not refer to a valid field")
 		}
 		return nil
 	}
@@ -382,6 +380,7 @@ func ValidFieldPath(jsonPath string, schema *schema.Structural) (validFieldPath
 	})
 
 	var tok string
+	var isNamed bool
 	for scanner.Scan() {
 		tok = scanner.Text()
 		switch tok {
@@ -397,7 +396,15 @@ func ValidFieldPath(jsonPath string, schema *schema.Structural) (validFieldPath
 			if err != nil {
 				return nil, fmt.Errorf("invalid string literal: %v", err)
 			}
-			if err := appendToPath(unescaped); err != nil {
+
+			if schema.Properties != nil {
+				isNamed = true
+			} else if schema.AdditionalProperties != nil {
+				isNamed = false
+			} else {
+				return nil, fmt.Errorf("does not refer to a valid field")
+			}
+			if err := appendToPath(unescaped, isNamed); err != nil {
 				return nil, err
 			}
 			if !scanner.Scan() {
@@ -412,7 +419,14 @@ func ValidFieldPath(jsonPath string, schema *schema.Structural) (validFieldPath
 				return nil, fmt.Errorf("unexpected end of JSON path")
 			}
 			tok = scanner.Text()
-			if err := appendToPath(tok); err != nil {
+			if schema.Properties != nil {
+				isNamed = true
+			} else if schema.AdditionalProperties != nil {
+				isNamed = false
+			} else {
+				return nil, fmt.Errorf("does not refer to a valid field")
+			}
+			if err := appendToPath(tok, isNamed); err != nil {
 				return nil, err
 			}
 		default:

staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/schema/cel/validation_test.go

@@ -2706,6 +2706,11 @@ func TestValidateFieldPath(t *testing.T) {
 					Type: "number",
 				},
 			},
+			"'foo'bar": {
+				Generic: schema.Generic{
+					Type: "number",
+				},
+			},
 			"a": {
 				Generic: schema.Generic{
 					Type: "object",
@@ -2799,6 +2804,20 @@ func TestValidateFieldPath(t *testing.T) {
 			schema:          &sts,
 			validFieldPath:  path.Child("a"),
 		},
+		{
+			name:            "Valid 'foo'bar",
+			fieldPath:       "['\\'foo\\'bar']",
+			pathOfFieldPath: path,
+			schema:          &sts,
+			validFieldPath:  path.Child("'foo'bar"),
+		},
+		{
+			name:            "Invalid 'foo'bar",
+			fieldPath:       ".\\'foo\\'bar",
+			pathOfFieldPath: path,
+			schema:          &sts,
+			errDetail:       "does not refer to a valid field",
+		},
 		{
 			name:            "Invalid with whitespace",
 			fieldPath:       ". a",
@@ -2987,7 +3006,7 @@ func TestValidateFieldPath(t *testing.T) {
 				t.Errorf("expected error to contain: %v, but get: %v", tc.errDetail, err)
 			}
 			if tc.validFieldPath != nil && tc.validFieldPath.String() != path.Child(validField.String()).String() {
-				t.Errorf("expected %v, got %v", tc.validFieldPath, validField)
+				t.Errorf("expected %v, got %v", tc.validFieldPath, path.Child(validField.String()))
 			}
 		})
 	}