softwaremill / softwaremill/tapir
Codec don't work with case class contain recursive Seq object
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- Scala
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Description
Tapir version: 0.14.4
Scala version: 2.13.2
Describe the bug
Tapir Codec don't work on case class which contains recursive Seq object and the jsonBody output is Seq/Vector object
How to reproduce?
First, we have a Book case class which contains a recursive Seq[Book]
case class Book(title: String, year: Int, entities: Seq[Book])
Next Step, we try to define endpoint and output is Seq[Book]
val bookEndpoint: Endpoint[String, Unit, Seq[Book], Stream[IO, Byte]] =
endpoint.get
.in("books" / path[String]("bookId"))
.out(
jsonBody[Seq[Book]]
.description("Corresponding book")
)
Then the error will come up at jsonBody[Seq[Book]]
Error:(57, 17) could not find implicit value for evidence parameter of type sttp.tapir.Schema[Seq[com.yahoo.astra.global.knowledge.serving.services.Book]]
jsonBody[Seq[Book]]
However, it work when you change the output from Seq/Vector to List
val bookEndpoint: Endpoint[String, Unit, List[Book], Stream[IO, Byte]] =
endpoint.get
.in("books" / path[String]("bookId"))
.out(
jsonBody[List[Book]]
.description("Corresponding book")
)
Contributor guide
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the jsonBody[Seq[Book]] example and compare its Schema derivation with the working jsonBody[List[Book]] case. Reproduce the failure using the recursive Book case class on Scala 2.13.2 and Tapir 0.14.4; done means Seq or Vector outputs compile while retaining support for recursive case classes.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- scala
- Domain
- api, backend
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100