integer support broken with yaml

[cboitel]

Two use cases:

1. use openapi3 to load a document and ensure some data unarmshaled from a file complies with one of the schema (using VisitJSON)
2. use openapi3.filter to validate a request complies with a loaded openapi document

In both use cases, if a schema references a type integer and data was unmarshaled from YAML, we end up with " unhandled value of type int" error. If file or request is using JSON, no error is reported.
=> for a file, one can workaround the issue by marshaling the read YAML to JSON and unmarshal it back from JSON
=> for openapi3filter, no workaround found as of today.

I believe this is due to the wrong assumption that all numbers will be using float type as this is the case for JSON (no integers, only floats => json unmarshaling returns float only)
=> https://github.com/getkin/kin-openapi/blob/master/openapi3/schema.go#L795 only references float
=> https://github.com/getkin/kin-openapi/blob/master/openapi3/schema.go#L998 checks for integers but not its format (int32/64)

Support for integers type and its associated formats (int32/int64) is required for non-JSON content-types.

[fenollp]

Sounds to me you're experiencing unintuitive YAML integer parsing but it might be something else.
Please provide minimal code reproducing the above mentioned error.

[cboitel]

Here is an example:

package main

import (
	"bytes"
	"context"
	"fmt"
	"net/http"

	"github.com/getkin/kin-openapi/openapi3"
	"github.com/getkin/kin-openapi/openapi3filter"
	legacyrouter "github.com/getkin/kin-openapi/routers/legacy"
)

var openapiDoc = []byte(`
openapi: 3.0.3
info:
  version: v0.1.0
  title: Integer Sample API
paths:
  /samples:
    post:
      description: Sample operation
      requestBody:
        content:
          application/yaml:
            schema:
              $ref: '#/components/schemas/sample'
          application/json:
            schema:
              $ref: '#/components/schemas/sample'
      responses:
        "200":
          description: ok
components:
  schemas:
    sample:
      type: object
      properties:
        integer:
          type: integer
        number:
          type: number
`)

func main() {

	loader := openapi3.NewLoader()
	doc, err := loader.LoadFromData(openapiDoc)
	if err != nil {
		panic(err)
	}
	err = doc.Validate(loader.Context)
	if err != nil {
		panic(err)
	}

	router, err := legacyrouter.NewRouter(doc)
	if err != nil {
		panic(err)
	}
	testBodyJson := bytes.NewBuffer([]byte(`{ "integer": 1, "number": 2 }`))
	httpReqJson, _ := http.NewRequest(http.MethodPost, "/samples", testBodyJson)
	httpReqJson.Header.Set("Content-Type", "application/json")
	// Find route
	routeJson, pathParamsJson, _ := router.FindRoute(httpReqJson)

	// Validate request
	jsonRequestValidationInput := &openapi3filter.RequestValidationInput{
		Request:    httpReqJson,
		PathParams: pathParamsJson,
		Route:      routeJson,
	}
	if err := openapi3filter.ValidateRequest(context.Background(), jsonRequestValidationInput); err != nil {
		panic(err)
	}
	fmt.Println("JSON valid request")

	testBodyYaml := bytes.NewBuffer([]byte(`
integer: 1
number: 2.0`))
	httpReqYaml, _ := http.NewRequest(http.MethodPost, "/samples", testBodyYaml)
	httpReqYaml.Header.Set("Content-Type", "application/yaml")
	// Find route
	routeYaml, pathParamsYaml, _ := router.FindRoute(httpReqYaml)

	// Validate request
	yamlRequestValidationInput := &openapi3filter.RequestValidationInput{
		Request:    httpReqYaml,
		PathParams: pathParamsYaml,
		Route:      routeYaml,
	}
	if err := openapi3filter.ValidateRequest(context.Background(), yamlRequestValidationInput); err != nil {
		panic(err)
	}
	fmt.Println("Yaml valid request")
}

Output gives:

JSON valid request
panic: request body has an error: doesn't match the schema: Error at "/integer": unhandled value of type int
Schema:
  {
    "type": "integer"
  }

Value:
  1


goroutine 1 [running]:
main.main()
        /home/cbtl/openapi3-yaml/main.go:93 +0x594
exit status 2

If you change yaml body to:

	testBodyYaml := bytes.NewBuffer([]byte(`
integer: 1.0
number: 2.0`))

it succeeds while it should not (integer is no longer an integer):

JSON valid request
Yaml valid request

[cboitel]

Note that the following code demonstrate that json encoding always return float64 even for integers while yaml returns int

package main

import (
	"encoding/json"
	"fmt"

	"gopkg.in/yaml.v2"
)

func main() {
	var jsonData map[string]interface{}
	err := json.Unmarshal([]byte(`{ "integer": 1, "number": 2 }`), &jsonData)
	if err != nil {
		panic(err)
	}
	fmt.Printf("jsonData.integer = %T(%v)\n", jsonData["integer"], jsonData["integer"])
	fmt.Printf("jsonData.number = %T(%v)\n", jsonData["number"], jsonData["number"])
	var yamlData map[string]interface{}
	err = yaml.Unmarshal([]byte(`
integer: 1
number: 2
`), &yamlData)
	if err != nil {
		panic(err)
	}
	fmt.Printf("yamlData.integer = %T(%v)\n", yamlData["integer"], yamlData["integer"])
	fmt.Printf("yamlData.number = %T(%v)\n", yamlData["number"], yamlData["number"])
}

Output:

jsonData.integer = float64(1)
jsonData.number = float64(2)
yamlData.integer = int(1)
yamlData.number = int(2)

Since kinopenapi only handles float64 as returned by json decoding, int from yaml aren't supported.
Note that encoding/json returns floats since in Javascript all numbers are floats.

[cboitel]

Submitted a PR to:

1. fix this (also added tests with YAML decoded data not only JSON data)
2. enhance integer support (added limit checks for int32/int64 formats)