## Summary:
We had this setting called "scalars", which said: bind this GraphQL type
to this Go type, rather than the one you would normally use. It's
called that because it's most useful for custom scalars, where "the one
you would normally use" is "error: unknown scalar". But nothing ever
stopped you from using it for a non-scalar type. I was planning on
removing this functionality, because it's sort of a rough edge, but a
discussion with Craig found some good use cases, so instead, in this
commit, I document it better and add some slightly nicer ways to specify
it.
Specifically, here are a few potential non-scalar use cases:
- bind a GraphQL enum to a nonstandard type (or even `string`)
- bind an input type to some type that has exactly the fields you want;
this acts as a sort of workaround for issues #14 and #44
- bind an object type to your own struct, so as to add methods to it
(this is the use case Craig raised)
- bind an object type to your own struct, so as to share it between
multiple queries (I believe named fragments will address this case
better, but it doesn't hurt to have options)
- bind a GraphQL list type to a non-slice type in Go (presumably one
with an UnmarshalJSON method), or any other different structure
The latter three cases still have the sharp edge I was originally
worried about, which is that nothing guarantees that the fields you
request in the query are the ones the type expects to get. But I think
it's worth having the option, with appropriate disclaimers.
The main change to help support that better is that you can now specify
the type inline in the query, as an alternative to specifying it in the
config file; this means you might map a given object to a given struct,
but only in some cases, and when you do you have a chance to look at the
list of fields you're requesting.
Additionally, I renamed the config field from "scalars" to "bindings"
(but mentioned it in a few places where you might go looking for how to
map scalars, most importantly the error message you get for an unknown
(custom) scalar). While I was making a breaking change, I also changed
it to be a `map[string]<struct>` instead of a `map[string]string`,
because I expect to add more fields soon, e.g. to handle issue #38.
Finally, since the feature is now intended/documented, I added some
tests, although it's honestly quite simple on the genqlient side.
## Test plan:
make tesc
Author: benjaminjkraft
Reviewers: csilvers, aberkan, dnerdy, MiguelCastillo
Required Reviewers:
Approved by: csilvers
Checks: ⌛ Test (1.17), ⌛ Test (1.16), ⌛ Test (1.15), ⌛ Test (1.14), ⌛ Test (1.13), ⌛ Lint, ⌛ Test (1.17), ⌛ Test (1.16), ⌛ Test (1.15), ⌛ Test (1.14), ⌛ Test (1.13), ⌛ Lint
Pull request URL: https://github.com/Khan/genqlient/pull/69
## Summary:
In this commit I begin the journey to add the long-awaited support for
interfaces (part of #8). Well, it's not the beginning: I already had
some half-written broken code around. But it's the first fully
functional support, and especially, the first *tested* support; it's
probably best to review the nontrivially-changed code as if it were new.
Conceptually, the code so far is pretty simple: we generate an interface
type, and the implementations. (That code is in fact mostly unchanged.)
The complexity comes in because encoding/json doesn't know how to
unmarshal that. So we have to add an UnmarshalJSON method, which
actually has to be on the types with interface-type fields, that knows
how. I factored it into two methods, such that that UnmarshalJSON
method is just glue, and then there's a separate function, corresponding
to each interface-type, that actually does all the work. (If only one
could just write it as an actual method!) The method uses the same
trick suggested to me by a few others in another context to deserialize
all but one field, then handle that field specially, which is discussed
in the code.
This still has some limitations, which will be lifted in future commits:
- it doesn't allow for list-of-interface fields
- it requires that you manually ask for `__typename`
- it doesn't support fragments, i.e. you can only query for interface
fields, not concrete-type-specific ones
But it works, even in integration tests, which is progress!
As a part of this, I added a proper config option for the "allow broken
features" flag, since I need to be able to set it from the integration
tests which are in a separate package (and actually shell out via `go
generate`). I also renamed what was to be the first case
(InterfaceNoFragments), and replaced it with a further-simplified
version (avoiding list-of-interface fields.
[1] https://github.com/benjaminjkraft/notes/blob/master/go-json-interfaces.md
Issue: https://github.com/Khan/genqlient/issues/8
## Test plan:
make tesc
Author: benjaminjkraft
Reviewers: dnerdy, benjaminjkraft, aberkan, csilvers, MiguelCastillo
Required Reviewers:
Approved by: dnerdy
Checks: ⌛ Test (1.17), ✅ Test (1.16), ⌛ Test (1.15), ⌛ Test (1.14), ⌛ Test (1.13), ✅ Lint, ✅ Test (1.17), ⌛ Test (1.16), ⌛ Test (1.15), ⌛ Test (1.14), ⌛ Test (1.13), ✅ Lint
Pull request URL: https://github.com/Khan/genqlient/pull/52
## Summary:
As Mark pointed out in a review where I realized that the *example* had
a bogus config key (which I hadn't noticed earlier because it was just
using the default value), we should probably do a strict-unmarshal;
there's no reason you should have random extra keys in your config and
if you do it's probably a mistake. (Or maybe you're running a too-old
version of genqlient for your codebase, which you probably also want to
know.) Now we do.
## Test plan:
- `make check`
- in webapp, `go mod edit -replace github.com/Khan/genqlient=../genqlient`
then `make genqlient` produces no diffs (except go.mod/go.sum).
Author: benjaminjkraft
Reviewers: dnerdy, aberkan, csilvers, MiguelCastillo
Required Reviewers:
Approved by: dnerdy
Checks: ✅ Test (1.17), ✅ Test (1.16), ✅ Test (1.15), ✅ Test (1.14), ✅ Test (1.13), ✅ Lint, ✅ Test (1.17), ✅ Test (1.16), ✅ Test (1.15), ✅ Test (1.14), ✅ Test (1.13), ✅ Lint
Pull request URL: https://github.com/Khan/genqlient/pull/55
