feat: sealed HttpError hierarchy with typed error bodies and HttpResult

[halotukozak]

Summary

• Replace generic HttpError data class with sealed HttpError<out B> hierarchy (14 predefined subtypes: BadRequest, Unauthorized, NotFound, Conflict, etc.)
• Add HttpResult<E, T> typealias over Either<HttpError<E>, HttpSuccess<T>>
• Rewrite ApiClientBaseGenerator: mapToResult branches on 12 status codes, deserializeErrorBody for typed error bodies, safeCall returns Either.Left(HttpError.Network) for network errors
• Rewrite ClientGenerator: methods return HttpResult<E, T>, resolveErrorType() reads 4xx/5xx response schemas for typed error bodies
• Remove HttpErrorType enum, remove Raise context from public API

Depends on: #24 (feat/security-schemes)

Test plan

• ApiResponseGeneratorTest — 12 tests for sealed hierarchy, subtypes, HttpResult typealias
• ApiClientBaseGeneratorTest — 7 new tests for mapToResult, deserializeErrorBody, safeCall
• ClientGeneratorTest — 7 new tests for HttpResult return type, resolveErrorType scenarios
• Manual: regenerate against cem-mobile-app specs

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR refactors the generated runtime/client response API to use a sealed HttpError<out B> hierarchy with typed error bodies and introduces HttpResult<E, T> (an Either<HttpError<E>, HttpSuccess<T>>) as the primary return type for generated client endpoints, removing the previous Arrow Raise-based public API.

Changes:

• Replaces HttpError data class + HttpErrorType enum with a sealed HttpError<out B> subtype hierarchy and adds HttpResult<E, T> typealias.
• Updates ApiClientBaseGenerator to return HttpResult via mapToResult, adds deserializeErrorBody, and returns HttpError.Network on network failures.
• Updates ClientGenerator so endpoint methods return HttpResult and adds error type inference from non-2xx OpenAPI response schemas.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
core/src/test/kotlin/com/avsystem/justworks/core/gen/ClientGeneratorTest.kt	Updates tests for HttpResult return types, removal of Raise context, and typed error resolution.
core/src/test/kotlin/com/avsystem/justworks/core/gen/ApiResponseGeneratorTest.kt	Adds coverage for sealed HttpError hierarchy and HttpResult typealias generation; removes HttpErrorType expectations.
core/src/test/kotlin/com/avsystem/justworks/core/gen/ApiClientBaseGeneratorTest.kt	Updates tests for HttpResult flow, typed error body deserialization, and network error mapping.
core/src/main/kotlin/com/avsystem/justworks/core/gen/Names.kt	Adds Arrow Either + HttpResult/deserializeErrorBody names and removes HttpErrorType name.
core/src/main/kotlin/com/avsystem/justworks/core/gen/ClientGenerator.kt	Switches endpoint return types to HttpResult and adds resolveErrorType() logic.
core/src/main/kotlin/com/avsystem/justworks/core/gen/ApiResponseGenerator.kt	Implements sealed HttpError<out B> and generates HttpResult typealias.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

buildBodySubtype generates a data class whose primary-constructor parameter body: B is not a property (it's later copied into a separate override val body). Kotlin requires all data class primary-constructor params to be val/var, and with out B this also places B in an 'in' position, which won’t compile. Consider making the primary-constructor parameter itself the overridden property (e.g., override val body: B?) and aligning its nullability with HttpError.body: B? to keep HttpError.BadRequest(...) compatible with HttpResult<E, T>.

Suggested change

	.addParameter(BODY, b)
	.build(),
	).addProperty(
	PropertySpec
	.builder(BODY, b)
	.initializer(BODY)
	.addModifiers(KModifier.OVERRIDE)
	.build(),
	).addProperty(
	PropertySpec
	.addParameter(
	ParameterSpec
	.builder(BODY, b.copy(nullable = true))
	.addModifiers(KModifier.OVERRIDE, KModifier.VAL)
	.build(),
	)
	.build(),
	).addProperty(
	PropertySpec

[Copilot]

buildOtherSubtype has the same issue as the other data class subtypes: it creates constructor parameters (code, body) that are not val/var properties and then adds separate properties initialized from them. This will not compile for a Kotlin data class, and out B is also used in a constructor-parameter position. Consider generating override val code: Int / override val body: B? directly in the primary constructor (and avoid a separate initializer property) so the resulting data class is valid Kotlin.

[Copilot]

deserializeErrorBody catches Exception, which will also swallow kotlinx.coroutines.CancellationException in suspend contexts and can break coroutine cancellation (requests may keep running despite cancellation). Prefer rethrowing CancellationException explicitly, or narrowing the catch to deserialization-related failures (e.g., SerializationException/IllegalStateException) so cancellation propagates correctly.

Suggested change

	.nextControlFlow("catch (_: %T)", Exception::class)
	.nextControlFlow("catch (e: %T)", Exception::class)
	.addStatement("if (e is kotlinx.coroutines.CancellationException) throw e")