Header value of string type is not validated against the pattern

[svkirillov]

The header value isn't validated properly if the value type is string. Judging by the code, validation only occurs if the schema specifies valid enum values; in all other cases, validation is completely ignored. If type: is left blank, the default validation for the schema will be triggered, and a validation error will be returned for invalid_value.

Versions in my go.mod

github.com/pb33f/libopenapi v0.28.0
github.com/pb33f/libopenapi-validator v0.6.4

Example

package main

import (
	"fmt"
	"net/http"

	"github.com/pb33f/libopenapi"
	"github.com/pb33f/libopenapi-validator/parameters"
)

func main() {
	spec := `openapi: 3.1.0
paths:
  /burgers/beef:
    get:
      parameters:
        - name: X-Request-Test
          in: header
          required: true
          schema:
            type: string
            format: uuid
            pattern: '^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$'
`

	doc, _ := libopenapi.NewDocument([]byte(spec))
	m, _ := doc.BuildV3Model()
	v := parameters.NewParameterValidator(&m.Model)

	request, _ := http.NewRequest(http.MethodGet, "https://things.com/burgers/beef", nil)
	request.Header.Add("X-Request-Test", "invalid_value")

	valid, errors := v.ValidateHeaderParams(request)

	fmt.Println(valid) // valid == True, should be False
	fmt.Println(errors) // errors == [], should be not empty
}