Cannot return an escaped string or json as field value in a verb response struct

[mistermoe]

Repro

offerings.go

package offerings

import (
	"context"
	"ftl/builtin"

	"ftl/rates"

	"github.com/TBD54566975/ftl/go-runtime/ftl"
)

type ApiError struct {
	Error string `json:"error"`
}

//ftl:export
//ftl:ingress GET /offerings
func GetOfferings(ctx context.Context, req builtin.HttpRequest[builtin.Empty]) (builtin.HttpResponse[builtin.Empty, ApiError], error) {
	log := ftl.LoggerFromContext(ctx)
	rate, err := ftl.Call(ctx, rates.GetRates, rates.RateRequest{})
	log.Infof("RATE! %v", rate)

	if err != nil {
		return builtin.HttpResponse[builtin.Empty, ApiError]{
			Status: 500,
			Error:  ftl.Some(ApiError{Error: "wottf"}),
		}, nil
	}

	return builtin.HttpResponse[builtin.Empty, ApiError]{
		Status: 200,
		Body:   ftl.Some(builtin.Empty{}),
	}, nil
}

rates.go

package rates

import (
	"context"
)

type RateRequest struct{}

type RateResponse struct {
	Rates string `json:"rates"`
}

//ftl:export
func GetRates(ctx context.Context, req RateRequest) (RateResponse, error) {
	return RateResponse{
		Rates: `"hi2u"`,
	}, nil
}

❯ curl -v 'http://localhost:8892/ingress/offerings'
*   Trying [::1]:8892...
* connect to ::1 port 8892 failed: Connection refused
*   Trying 127.0.0.1:8892...
* Connected to localhost (127.0.0.1) port 8892
> GET /ingress/offerings HTTP/1.1
> Host: localhost:8892
> User-Agent: curl/8.4.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Content-Type: application/json; charset=utf-8
< Date: Mon, 08 Apr 2024 04:43:58 GMT
< Content-Length: 17
<
* Connection #0 to host localhost left intact
{"error":"wottf"}

terminal running ftl dev:

error:controller0: failed to record call: ERROR: invalid input syntax for type json (SQLSTATE 22P02)
info:ledger: RATE! {}

Other Thoughts

• JSONB.

[alecthomas]

Found what is happening. The response is:

{"rates":""hi2u""}