Files
genqlient/generate/testdata/snapshots/TestGenerate-SimpleInlineFragment.graphql-SimpleInlineFragment.graphql.go
T
Ben KraftandGitHub 65c3e20ee6 Fix bugs relating to optional fields with custom (un)marshalers (#116)
## Summary:
There were a few bugs here, one of which Craig came across when pulling
the custom-unmarshaler change into webapp:
1. If you have an optional field with a custom unmarshaler, and the
   server omits the field from the response entirely (i.e. does not
   write `"myField": null`), we would still call your unmarshaler with
   an input of `[]byte(nil)`.  This is just wrong; it's our job to do
   the nil-check.  (This is the one Craig found; in practice gqlgen
   servers do not do this and I think the spec says not to although it's
   a bit fuzzy on the matter of serialization.  But in practice we have
   mocks that do it -- for required fields even! -- and it seems better
   to handle it than pass you data on which you'll probably err or even
   panic.)
2. If you have an optional field with a custom unmarshaler, and the
   server returns an explicit null (i.e. `"myField": null`), we would
   call your unmarshaler with `[]byte("null")`.  In principle the intent
   was you're supposed to implement that, as [`json.Unmarshaler`
   advises][1].  But (a) I forgot to document that, and (b) in practice
   `json.Unmarshal` [does *not* call you in that case][2], i.e. its
   advice is unnecessary.  So I think it's better for us to just match
   it, and not call you.  (And in that case I see no reason to bother
   documenting the advice.)
3. If you have an optional, `pointer: true` field with a custom
   marshaler, the reverse of (2) applies: if the pointer is nil, we
   shouldn't really call you.  (Indeed if you were a real
   `json.Marshaler` with a value-method rather than a pointer-method,
   trying to call you might panic!)  Note we don't need to explicitly
   write "null"; we just leave the `json.RawMessage` as nil, and
   `json.Marshal` [handles that][3].
4. We handle interface types effectively the same as custom
   unmarshalers, just we generate the unmarshaler.  So if you have an
   optional field with interface type, (1) would also apply there; our
   generated unmarshaler returns an error in this case.
5. While (2) doesn't apply to such optional interface fields (because we
   do the customary `if string(b) == "null"` check -- this I at least
   thought to test), if you set `pointer: true` on the field, we would
   still call the unmarshaler on the value, and it would no-op, but only
   *after* we initialized the pointer.  Put more simply, we'd return a
   non-nil pointer to nil interface, rather than a nil pointer; this is
   wrong since the whole point of `pointer: true` is you only get a
   non-nil pointer if your value is nil!  Of course, in practice there's
   little reason to use `pointer: true` on interface fields, and indeed
   this stuff gets so confusing my test was even wrong.

In this commit I fix all the bugs, by adding appropriate nil-checks to
wrap the unmarshaler-calls.  The templates are, as always, a bit
confusing, but the generated code makes it clear what changed.

Note we'll want to land this before cutting a release with custom
marshaler/unmarshaler support, because the first three bugs are
potentially quite noticeable.  (The latter two are in `v0.1.0`, but
presumably quite rare.)

[1]: https://pkg.go.dev/encoding/json#Unmarshaler
[2]: https://play.golang.org/p/Pw6zNN8trGO
[3]: https://play.golang.org/p/crTfnT7ePte

Issue: https://phabricator.khanacademy.org/D74453#inline-558571

## Test plan:
make tesc


Author: benjaminjkraft

Reviewers: csilvers, StevenACoffman, benjaminjkraft, aberkan, dnerdy, jvoll, mahtabsabet, MiguelCastillo

Required Reviewers: 

Approved By: csilvers, StevenACoffman

Checks:  Test (1.17),  Test (1.16),  Test (1.15),  Test (1.14),  Lint,  Test (1.17),  Test (1.16),  Test (1.15),  Test (1.14),  Lint

Pull Request URL: https://github.com/Khan/genqlient/pull/116
2021-09-27 20:35:39 -07:00

197 lines
6.1 KiB
Go

package test
// Code generated by github.com/Khan/genqlient, DO NOT EDIT.
import (
"encoding/json"
"fmt"
"github.com/Khan/genqlient/graphql"
"github.com/Khan/genqlient/internal/testutil"
)
// SimpleInlineFragmentRandomItemArticle includes the requested fields of the GraphQL type Article.
type SimpleInlineFragmentRandomItemArticle struct {
Typename string `json:"__typename"`
// ID is the identifier of the content.
Id testutil.ID `json:"id"`
Name string `json:"name"`
Text string `json:"text"`
}
// SimpleInlineFragmentRandomItemContent includes the requested fields of the GraphQL interface Content.
//
// SimpleInlineFragmentRandomItemContent is implemented by the following types:
// SimpleInlineFragmentRandomItemArticle
// SimpleInlineFragmentRandomItemVideo
// SimpleInlineFragmentRandomItemTopic
// The GraphQL type's documentation follows.
//
// Content is implemented by various types like Article, Video, and Topic.
type SimpleInlineFragmentRandomItemContent interface {
implementsGraphQLInterfaceSimpleInlineFragmentRandomItemContent()
// GetTypename returns the receiver's concrete GraphQL type-name (see interface doc for possible values).
GetTypename() string
// GetId returns the interface-field "id" from its implementation.
// The GraphQL interface field's documentation follows.
//
// ID is the identifier of the content.
GetId() testutil.ID
// GetName returns the interface-field "name" from its implementation.
GetName() string
}
func (v *SimpleInlineFragmentRandomItemArticle) implementsGraphQLInterfaceSimpleInlineFragmentRandomItemContent() {
}
// GetTypename is a part of, and documented with, the interface SimpleInlineFragmentRandomItemContent.
func (v *SimpleInlineFragmentRandomItemArticle) GetTypename() string { return v.Typename }
// GetId is a part of, and documented with, the interface SimpleInlineFragmentRandomItemContent.
func (v *SimpleInlineFragmentRandomItemArticle) GetId() testutil.ID { return v.Id }
// GetName is a part of, and documented with, the interface SimpleInlineFragmentRandomItemContent.
func (v *SimpleInlineFragmentRandomItemArticle) GetName() string { return v.Name }
func (v *SimpleInlineFragmentRandomItemVideo) implementsGraphQLInterfaceSimpleInlineFragmentRandomItemContent() {
}
// GetTypename is a part of, and documented with, the interface SimpleInlineFragmentRandomItemContent.
func (v *SimpleInlineFragmentRandomItemVideo) GetTypename() string { return v.Typename }
// GetId is a part of, and documented with, the interface SimpleInlineFragmentRandomItemContent.
func (v *SimpleInlineFragmentRandomItemVideo) GetId() testutil.ID { return v.Id }
// GetName is a part of, and documented with, the interface SimpleInlineFragmentRandomItemContent.
func (v *SimpleInlineFragmentRandomItemVideo) GetName() string { return v.Name }
func (v *SimpleInlineFragmentRandomItemTopic) implementsGraphQLInterfaceSimpleInlineFragmentRandomItemContent() {
}
// GetTypename is a part of, and documented with, the interface SimpleInlineFragmentRandomItemContent.
func (v *SimpleInlineFragmentRandomItemTopic) GetTypename() string { return v.Typename }
// GetId is a part of, and documented with, the interface SimpleInlineFragmentRandomItemContent.
func (v *SimpleInlineFragmentRandomItemTopic) GetId() testutil.ID { return v.Id }
// GetName is a part of, and documented with, the interface SimpleInlineFragmentRandomItemContent.
func (v *SimpleInlineFragmentRandomItemTopic) GetName() string { return v.Name }
func __unmarshalSimpleInlineFragmentRandomItemContent(b []byte, v *SimpleInlineFragmentRandomItemContent) error {
if string(b) == "null" {
return nil
}
var tn struct {
TypeName string `json:"__typename"`
}
err := json.Unmarshal(b, &tn)
if err != nil {
return err
}
switch tn.TypeName {
case "Article":
*v = new(SimpleInlineFragmentRandomItemArticle)
return json.Unmarshal(b, *v)
case "Video":
*v = new(SimpleInlineFragmentRandomItemVideo)
return json.Unmarshal(b, *v)
case "Topic":
*v = new(SimpleInlineFragmentRandomItemTopic)
return json.Unmarshal(b, *v)
case "":
return fmt.Errorf(
"Response was missing Content.__typename")
default:
return fmt.Errorf(
`Unexpected concrete type for SimpleInlineFragmentRandomItemContent: "%v"`, tn.TypeName)
}
}
// SimpleInlineFragmentRandomItemTopic includes the requested fields of the GraphQL type Topic.
type SimpleInlineFragmentRandomItemTopic struct {
Typename string `json:"__typename"`
// ID is the identifier of the content.
Id testutil.ID `json:"id"`
Name string `json:"name"`
}
// SimpleInlineFragmentRandomItemVideo includes the requested fields of the GraphQL type Video.
type SimpleInlineFragmentRandomItemVideo struct {
Typename string `json:"__typename"`
// ID is the identifier of the content.
Id testutil.ID `json:"id"`
Name string `json:"name"`
Duration int `json:"duration"`
}
// SimpleInlineFragmentResponse is returned by SimpleInlineFragment on success.
type SimpleInlineFragmentResponse struct {
RandomItem SimpleInlineFragmentRandomItemContent `json:"-"`
}
func (v *SimpleInlineFragmentResponse) UnmarshalJSON(b []byte) error {
if string(b) == "null" {
return nil
}
var firstPass struct {
*SimpleInlineFragmentResponse
RandomItem json.RawMessage `json:"randomItem"`
graphql.NoUnmarshalJSON
}
firstPass.SimpleInlineFragmentResponse = v
err := json.Unmarshal(b, &firstPass)
if err != nil {
return err
}
{
dst := &v.RandomItem
src := firstPass.RandomItem
if len(src) != 0 && string(src) != "null" {
err = __unmarshalSimpleInlineFragmentRandomItemContent(
src, dst)
if err != nil {
return fmt.Errorf(
"Unable to unmarshal SimpleInlineFragmentResponse.RandomItem: %w", err)
}
}
}
return nil
}
func SimpleInlineFragment(
client graphql.Client,
) (*SimpleInlineFragmentResponse, error) {
var err error
var retval SimpleInlineFragmentResponse
err = client.MakeRequest(
nil,
"SimpleInlineFragment",
`
query SimpleInlineFragment {
randomItem {
__typename
id
name
... on Article {
text
}
... on Video {
duration
}
}
}
`,
&retval,
nil,
)
return &retval, err
}