[scala-sttp4-jsoniter] support set parameters (uniqueItems arrays) in query, header, path and cookie parameters by reynaldjoabet · Pull Request #24301 · OpenAPITools/openapi-generator

reynaldjoabet · 2026-07-14T17:34:47Z

Parameters whose schema has uniqueItems: true are generated as Scala Set, but the serializers only matched Seq, so any Set parameter — including Set[String] — failed to compile with a Mirror.Of[Set[...]] error. This predates the enum-array work; Set was never handled.

Add Set[p] / Option[Set[p]] cases to FormSerializable, HeaderSerializable, PathSerializable and CookieSerializable. Because Set is invariant (unlike the covariant Seq), the element type is bound and dispatched on via erasedValue: primitives and enums both convert to Seq and reuse the existing array serialization, so all style/explode combinations keep working. Non-enum, non-primitive element types fail with a clear compile-time error.

Extend the sample spec with a Set of referenced enums (colors/PetColor) and a Set of primitives (uniqueTags) so the samples build exercises both paths.

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Summary by cubic

Support Set[...] parameters in scala-sttp4-jsoniter across query, header, path, and cookie, and fix form serialization to omit empty arrays/sets. This unblocks uniqueItems arrays generated as Scala sets and avoids emitting empty param entries.

Bug Fixes
- Added Set[p] and Option[Set[p]] handling to Form, Header, Path, and Cookie serializers; supports primitives and referenced enums, with unsupported element types failing at compile time.
- Form serialization now omits empty arrays/sets when explode=false (no name=), matching explode=true and optional semantics. Updated samples/spec to cover sets: added PetColor enum and uniqueTags, and extended findPetsByTags with colors: Set[PetColor] and uniqueTags: Set[String].

^{Written for commit 19350b7. Summary will update on new commits.}

… query, header, path and cookie parameters Parameters whose schema has `uniqueItems: true` are generated as Scala `Set`, but the serializers only matched `Seq`, so any `Set` parameter — including `Set[String]` — failed to compile with a `Mirror.Of[Set[...]]` error. This predates the enum-array work; `Set` was never handled. Add `Set[p]` / `Option[Set[p]]` cases to FormSerializable, HeaderSerializable, PathSerializable and CookieSerializable. Because `Set` is invariant (unlike the covariant `Seq`), the element type is bound and dispatched on via `erasedValue`: primitives and enums both convert to `Seq` and reuse the existing array serialization, so all style/explode combinations keep working. Non-enum, non-primitive element types fail with a clear compile-time error. Extend the sample spec with a `Set` of referenced enums (colors/PetColor) and a `Set` of primitives (uniqueTags) so the samples build exercises both paths.

cubic-dev-ai

2 issues found across 7 files

Prompt for AI agents (unresolved issues)


Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="samples/client/petstore/scala-sttp4-jsoniter/README.md">

<violation number="1" location="samples/client/petstore/scala-sttp4-jsoniter/README.md:98">
P2: The new Models entry points to `PetColor.md`, but this generated sample does not contain that file, so the README link returns a missing page. Adding the generated model documentation (or removing this entry until it is generated) keeps the model index navigable.</violation>
</file>

<file name="samples/client/petstore/scala-sttp4-jsoniter/src/main/scala/org/openapitools/client/api/PetApi.scala">

<violation number="1" location="samples/client/petstore/scala-sttp4-jsoniter/src/main/scala/org/openapitools/client/api/PetApi.scala:134">
P2: An empty optional `colors` set is serialized as `colors=` rather than omitted. This can make a request behave differently from the OpenAPI contract (and may be rejected as an invalid empty color); guarding serialization on `colors.nonEmpty` would preserve omission semantics.</violation>
</file>

_{Reply with feedback, questions, or to request a fix.

Re-trigger cubic}

cubic-dev-ai · 2026-07-14T17:42:37Z

 - [Category](Category.md)
 - [Order](Order.md)
 - [Pet](Pet.md)
+ - [PetColor](PetColor.md)


P2: The new Models entry points to PetColor.md, but this generated sample does not contain that file, so the README link returns a missing page. Adding the generated model documentation (or removing this entry until it is generated) keeps the model index navigable.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At samples/client/petstore/scala-sttp4-jsoniter/README.md, line 98: <comment>The new Models entry points to `PetColor.md`, but this generated sample does not contain that file, so the README link returns a missing page. Adding the generated model documentation (or removing this entry until it is generated) keeps the model index navigable.</comment> <file context> @@ -95,6 +95,7 @@ Class | Method | HTTP request | Description - [Category](Category.md) - [Order](Order.md) - [Pet](Pet.md) + - [PetColor](PetColor.md) - [PetStatus](PetStatus.md) - [Tag](Tag.md) </file context>

this generator doesn't come with auto-generated docs for APIs and models at the moment. would be nice to have but definitely not within the scope of this change.

You're right that the generator doesn't produce those API/model docs yet, so that part is out of scope for this change. The parent comment was too broad for this PR.

cubic-dev-ai · 2026-07-14T17:42:37Z

    val requestURL =
      uri"$baseUrl/pet/findByTags"
        .addParams(FormSerializable.serialize("tags", tags, FormStyleFormat.FORM, false): _*)
+        .addParams(FormSerializable.serialize("colors", colors, FormStyleFormat.FORM, false): _*)


P2: An empty optional colors set is serialized as colors= rather than omitted. This can make a request behave differently from the OpenAPI contract (and may be rejected as an invalid empty color); guarding serialization on colors.nonEmpty would preserve omission semantics.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At samples/client/petstore/scala-sttp4-jsoniter/src/main/scala/org/openapitools/client/api/PetApi.scala, line 134: <comment>An empty optional `colors` set is serialized as `colors=` rather than omitted. This can make a request behave differently from the OpenAPI contract (and may be rejected as an invalid empty color); guarding serialization on `colors.nonEmpty` would preserve omission semantics.</comment> <file context> @@ -121,11 +124,15 @@ case class PetApi[Auth <: org.openapitools.client.core.Authorization] private (b val requestURL = uri"$baseUrl/pet/findByTags" .addParams(FormSerializable.serialize("tags", tags, FormStyleFormat.FORM, false): _*) + .addParams(FormSerializable.serialize("colors", colors, FormStyleFormat.FORM, false): _*) + .addParams(FormSerializable.serialize("uniqueTags", uniqueTags, FormStyleFormat.FORM, true): _*) </file context>

Note: this empty-collection behavior is pre-existing, not introduced by this PR. The explode=false branch of serializeArray has always emitted name= for an empty collection (Seq(paramName -> values.map(_.asString).mkString(",")) with no empty guard), and it's shipped on master in the primitive Seq path since before the enum-array and Set work — so it already affects existing array params like status/tags, not just the new Set params. This change fixes it at the source (serializeArray), making explode=false consistent with explode=true, which already omits empty collections.

…n instead of emitting name= An empty array/set parameter with explode=false previously serialized as `name=` rather than being omitted, unlike explode=true which already dropped it. For an optional collection an empty value means "not provided" and should not appear in the request. Guard serializeArray so an empty collection yields no entries, making explode=false consistent with explode=true.

wing328 · 2026-07-15T12:17:33Z

Thanks for the PR, which has been merged

FYI @clasnake (2017/07), @shijinkui (2018/01), @ramzimaalej (2018/03), @chameleon82 (2020/03), @Bouillie (2020/04) @Fish86 (2023/06)

cubic-dev-ai Bot reviewed Jul 14, 2026

View reviewed changes

wing328 added Client: Scala Enhancement: General labels Jul 14, 2026

wing328 added this to the 7.24.0 milestone Jul 14, 2026

wing328 merged commit 0d093a4 into OpenAPITools:master Jul 15, 2026
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[scala-sttp4-jsoniter] support set parameters (uniqueItems arrays) in query, header, path and cookie parameters - #24301

[scala-sttp4-jsoniter] support set parameters (uniqueItems arrays) in query, header, path and cookie parameters#24301
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reynaldjoabet:scala-sttp4-jsoniter-set-params

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