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
2.3 KiB
2.3 KiB
Changelog
next
Breaking changes:
- The
graphql.Clientinterface now acceptsvariables interface{}(containing a JSON-marshalable value) rather thanvariables map[string]interface{}. Clients implementing the interface themselves will need to change the signature; clients who simply callgraphql.NewClientare unaffected. - genqlient's handling of the
omitemptyoption has changed to match that ofencoding/json, from which it had inadvertently differed. In particular, this means struct-typed arguments with# @genqlient(omitempty: true)will no longer be omitted if they are the zero value. (Struct-pointers are still omitted if nil, so addingpointer: truewill typically work fine. It's also now possible to use a custom marshaler to explicitly map zero to null.)
New features:
- The new
bindings.marshalerandbindings.unmarshaleroptions ingenqlient.yamlallow binding to a type without using its standard JSON serialization; see the documentation for details. - Multiple genqlient directives may now be applied to the same node, as long as they don't conflict; see the directive documentation for details.
Bug fixes:
- The
omitemptyoption now works correctly for struct- and map-typed variables, matchingencoding/json, which is to say it never omits structs, and omits empty maps. (#43) - Generated type-names now abbreviate across multiple components; for example if the path to a type is
(MyOperation, Outer, Outer, Inner, OuterInner), it will again be calledMyOperationOuterInner. (This regressed in a pre-v0.1.0 refactor.) (#109) - Previously, interface fields with
# @genqlient(pointer: true)would be unmarshaled to(*MyInterface)(*<nil>), i.e. a pointer to the untyped-nil of the interface type. Now they are unmarshaled as(*MyInterface)(<nil>), i.e. a nil pointer of the pointer-to-interface type, as you would expect.
v0.1.0
First open-sourced version.