Ben KraftandGitHub
65c3e20ee6
## 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
140 lines
3.2 KiB
Go
140 lines
3.2 KiB
Go
package server
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import (
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"context"
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"fmt"
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"net/http/httptest"
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"github.com/99designs/gqlgen/graphql/handler"
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"github.com/99designs/gqlgen/graphql/handler/transport"
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)
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func strptr(v string) *string { return &v }
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func intptr(v int) *int { return &v }
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var users = []*User{
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{
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ID: "1", Name: "Yours Truly", LuckyNumber: intptr(17),
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Birthdate: strptr("2025-01-01"),
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Hair: &Hair{Color: strptr("Black")},
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},
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{ID: "2", Name: "Raven", LuckyNumber: intptr(-1), Hair: nil},
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}
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var animals = []*Animal{
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{
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ID: "3", Name: "Fido", Species: SpeciesDog, Owner: userByID("1"),
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Hair: &BeingsHair{HasHair: true},
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},
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{
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ID: "4", Name: "Old One", Species: SpeciesCoelacanth, Owner: nil,
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Hair: &BeingsHair{HasHair: false},
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},
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}
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func userByID(id string) *User {
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for _, user := range users {
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if id == user.ID {
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return user
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}
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}
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return nil
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}
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func usersByBirthdates(dates []string) []*User {
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var retval []*User
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for _, date := range dates {
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for _, user := range users {
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if user.Birthdate != nil && *user.Birthdate == date {
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retval = append(retval, user)
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}
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}
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}
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return retval
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}
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func beingByID(id string) Being {
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for _, user := range users {
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if id == user.ID {
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return user
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}
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}
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for _, animal := range animals {
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if id == animal.ID {
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return animal
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}
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}
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return nil
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}
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func (r *queryResolver) Me(ctx context.Context) (*User, error) {
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return userByID("1"), nil
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}
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func (r *queryResolver) User(ctx context.Context, id *string) (*User, error) {
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if id == nil {
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return userByID("1"), nil
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}
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return userByID(*id), nil
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}
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func (r *queryResolver) Being(ctx context.Context, id string) (Being, error) {
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return beingByID(id), nil
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}
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func (r *queryResolver) Beings(ctx context.Context, ids []string) ([]Being, error) {
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ret := make([]Being, len(ids))
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for i, id := range ids {
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ret[i] = beingByID(id)
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}
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return ret, nil
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}
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func (r *queryResolver) LotteryWinner(ctx context.Context, number int) (Lucky, error) {
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for _, user := range users {
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if user.LuckyNumber != nil && *user.LuckyNumber == number {
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return user, nil
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}
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}
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return nil, nil
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}
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func (r *queryResolver) UsersBornOn(ctx context.Context, date string) ([]*User, error) {
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return usersByBirthdates([]string{date}), nil
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}
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func (r *queryResolver) UsersBornOnDates(ctx context.Context, dates []string) ([]*User, error) {
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return usersByBirthdates(dates), nil
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}
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func (r *queryResolver) UserSearch(ctx context.Context, birthdate *string, id *string) ([]*User, error) {
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switch {
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case birthdate == nil && id != nil:
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return []*User{userByID(*id)}, nil
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case birthdate != nil && id == nil:
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return usersByBirthdates([]string{*birthdate}), nil
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default:
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return nil, fmt.Errorf("need exactly one of birthdate or id")
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}
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}
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func (r *queryResolver) Fail(ctx context.Context) (*bool, error) {
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f := true
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return &f, fmt.Errorf("oh no")
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}
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func RunServer() *httptest.Server {
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gqlgenServer := handler.New(NewExecutableSchema(Config{Resolvers: &resolver{}}))
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gqlgenServer.AddTransport(transport.POST{})
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return httptest.NewServer(gqlgenServer)
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}
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type (
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resolver struct{}
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queryResolver struct{}
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)
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func (r *resolver) Query() QueryResolver { return &queryResolver{} }
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//go:generate go run github.com/99designs/gqlgen
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