## Summary:
In this commit I add support for inline fragments
(`... on MyType { fields }`) to genqlient. This will make interfaces a
lot more useful! In future commits I'll add named fragments, for which
we'll generate slightly different types, as discussed in DESIGN.md.
In general, implementing the flattening approach described in DESIGN.md
was... surprisingly easy. All we have to do is recurse on applicable
fragments when generating our selection-set. The refactor to
selection-set handling this encouraged was, I think, quite beneficial.
It did reveal two tricky pre-existing issues.
One issue is that GraphQL allows for duplicate selections, as long as
they match. (In practice, this is only useful in the context of
fragments, although GraphQL allows it even without.) I decided to handle
the simple case (duplicate leaf fields; we just deduplicate) but leave
to the future the complex cases where we need to merge different
sub-selections (now #64). For now we just forbid that; we can see how
much it comes up.
The other issue is that we are generating type-names incorrectly for
interface types; I had intended to do `MyInterfaceMyFieldMyType` for
shared fields and `MyImplMyFieldMyType` for non-shared ones, but instead
I did `MyFieldMyType`, which is inconsistent already and can result in
conflicts in the presence of fragments. I'm going to fix this in a
separate commit, though, because it's going to require some refactoring
and is irrelevant to the main logic of this commit; I left some TODOs in
the tests related to this.
Issue: https://github.com/Khan/genqlient/issues/8
## Test plan:
make check
Author: benjaminjkraft
Reviewers: dnerdy, aberkan, 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/65
## 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 remove one of the limitations of our support for
interfaces, from #52, by adding support for list-of-interface fields.
This was surprisingly complex! The issue is that, as before, it's the
containing type that has to do all the glue work -- and it's that glue
work that is complicated by list-of-interface fields.
All in all, it's not that much new code, and by far the hard part is
just 20 lines in the UnmarshalJSON template (which come with almost
twice as many lines of comments to explain them). It may be easiest to
start by reading some of the generated code, and then read the template.
I also added support for such fields with `pointer: true` specified,
such that the type is `[][]...[]*MyInterface`, although I don't know why
you would want that. This does *not* allow e.g. `*[]*[][]*MyInterface`;
that would require a way to specify it (see #16) but also add some extra
complexity (as we'd have to actually walk the type-unwrap chain
properly, instead of just counting the number of slices and whether
there's a pointer).
Issue: https://github.com/Khan/genqlient/issues/8
## Test plan:
make check
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, ⌛ Lint, ⌛ Test (1.17), ⌛ Test (1.16), ⌛ Test (1.15), ⌛ Test (1.14), ⌛ Test (1.13)
Pull request URL: https://github.com/Khan/genqlient/pull/54
## 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
