Gradle plugin with multi-spec support

[halotukozak]

Summary

• JustworksPlugin — registers tasks per spec configuration
• JustworksExtension with NamedDomainObjectContainer for multi-spec DSL
• JustworksGenerateTask — wires parser + generators into Gradle task
• JustworksSharedTypesTask — generates shared API response types
• JustworksSpecConfiguration — per-spec configuration (specFile, packages, outputDir)
• Functional test suite

Test plan

• ./gradlew plugin:test passes
• ./gradlew core:test passes

Depends on #4

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Adds a dedicated Gradle plugin module to generate Kotlin clients/models from multiple OpenAPI specs, and extends the core parser/generators with polymorphism, inline-schema handling, and shared response types.

Changes:

• Introduces plugin subproject with justworks { specs { ... } } multi-spec DSL and generation tasks (including shared types).
• Expands core OpenAPI parsing/validation and codegen (oneOf/anyOf/allOf, inline schema dedup, serializers module, response wrappers).
• Adds extensive unit + functional test coverage and test resources for parser/codegen.

Reviewed changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
settings.gradle.kts	Adds plugin subproject to the build.
.gitignore	Ignores Gradle/Kotlin/IDE build artifacts.
core/build.gradle.kts	Adds Arrow + compiler args; ktlint pin workaround.
core/src/main/kotlin/com/avsystem/justworks/core/Generator.kt	Adds placeholder generator entry point.
core/src/main/kotlin/com/avsystem/justworks/core/gen/ApiResponseGenerator.kt	Generates shared HttpError/HttpSuccess types.
core/src/main/kotlin/com/avsystem/justworks/core/gen/ClientGenerator.kt	Generates Ktor client code per tag + error handling.
core/src/main/kotlin/com/avsystem/justworks/core/gen/InlineSchemaDeduplicator.kt	Adds inline schema structural dedup + naming collision handling.
core/src/main/kotlin/com/avsystem/justworks/core/gen/ModelGenerator.kt	Adds polymorphic + inline schema generation features and defaults.
core/src/main/kotlin/com/avsystem/justworks/core/gen/NameUtils.kt	Adds name transformations for identifiers/enum constants/ops.
core/src/main/kotlin/com/avsystem/justworks/core/gen/Names.kt	Centralizes KotlinPoet references for generator output.
core/src/main/kotlin/com/avsystem/justworks/core/gen/SerializersModuleGenerator.kt	Emits generatedSerializersModule for polymorphic types.
core/src/main/kotlin/com/avsystem/justworks/core/gen/TypeMapping.kt	Maps TypeRef to KotlinPoet TypeNames.
core/src/main/kotlin/com/avsystem/justworks/core/model/ApiSpec.kt	Introduces parsed model layer (ApiSpec, SchemaModel, etc.).
core/src/main/kotlin/com/avsystem/justworks/core/model/TypeRef.kt	Adds TypeRef IR including inline schemas.
core/src/main/kotlin/com/avsystem/justworks/core/parser/SpecParser.kt	Implements parsing + validation + $ref + combinator handling.
core/src/main/kotlin/com/avsystem/justworks/core/parser/SpecValidator.kt	Adds spec validation issues (errors + warnings).
core/src/test/kotlin/com/avsystem/justworks/core/gen/ApiResponseGeneratorTest.kt	Tests shared response type generation.
core/src/test/kotlin/com/avsystem/justworks/core/gen/ClientGeneratorTest.kt	Tests generated client structure and request wiring.
core/src/test/kotlin/com/avsystem/justworks/core/gen/InlineSchemaDedupTest.kt	Tests inline schema dedup + naming collision behavior.
core/src/test/kotlin/com/avsystem/justworks/core/gen/ModelGeneratorPolymorphicTest.kt	Tests polymorphic model generation behaviors.
core/src/test/kotlin/com/avsystem/justworks/core/gen/ModelGeneratorTest.kt	Tests model generation incl defaults + keywords + aliases.
core/src/test/kotlin/com/avsystem/justworks/core/gen/NameUtilsTest.kt	Tests name/identifier conversion utilities.
core/src/test/kotlin/com/avsystem/justworks/core/gen/SerializersModuleGeneratorTest.kt	Tests serializers module generation output.
core/src/test/kotlin/com/avsystem/justworks/core/gen/TypeMappingTest.kt	Tests TypeRef -> Kotlin type mapping.
core/src/test/kotlin/com/avsystem/justworks/core/parser/SpecParserPolymorphicTest.kt	Tests oneOf/allOf/discriminator parsing outcomes.
core/src/test/kotlin/com/avsystem/justworks/core/parser/SpecParserTest.kt	Tests parser correctness across refs/v2/anyOf errors.
core/src/test/kotlin/com/avsystem/justworks/core/parser/SpecValidatorTest.kt	Tests validation issue detection.
core/src/test/resources/anyof-spec.yaml	Adds anyOf test fixture.
core/src/test/resources/anyof-valid-spec.yaml	Adds discriminator + anyOf test fixture.
core/src/test/resources/invalid-spec.yaml	Adds invalid spec fixture for error tests.
core/src/test/resources/mixed-combinator-spec.yaml	Adds mixed combinator fixture for failure tests.
core/src/test/resources/petstore-v2.json	Adds Swagger v2 conversion fixture.
core/src/test/resources/petstore.yaml	Adds OpenAPI v3 petstore fixture.
core/src/test/resources/polymorphic-spec.yaml	Adds oneOf/allOf polymorphism fixture.
core/src/test/resources/refs-spec.yaml	Adds $ref resolution fixture.
plugin/build.gradle.kts	Defines Gradle plugin + functionalTest source set.
plugin/src/functionalTest/kotlin/com/avsystem/justworks/gradle/JustworksPluginFunctionalTest.kt	End-to-end TestKit coverage for multi-spec plugin.
plugin/src/main/kotlin/com/avsystem/justworks/gradle/JustworksExtension.kt	Adds multi-spec DSL extension container.
plugin/src/main/kotlin/com/avsystem/justworks/gradle/JustworksGenerateTask.kt	Cacheable generation task wiring parser + generators.
plugin/src/main/kotlin/com/avsystem/justworks/gradle/JustworksPlugin.kt	Registers tasks per spec + source-set wiring.
plugin/src/main/kotlin/com/avsystem/justworks/gradle/JustworksSharedTypesTask.kt	Cacheable task to generate shared response types.
plugin/src/main/kotlin/com/avsystem/justworks/gradle/JustworksSpecConfiguration.kt	Adds per-spec configuration object.

Comments suppressed due to low confidence (2)

plugin/src/main/kotlin/com/avsystem/justworks/gradle/JustworksSpecConfiguration.kt:1

• The KDoc DSL example uses specFile = ... / packageName = ..., but these are val Gradle Property types; assignment won’t compile in Kotlin DSL. Update the docs to use specFile.set(file(...)) and packageName.set("...") (and similarly for apiPackage/modelPackage), or change the API to expose Kotlin-DSL-friendly setters (e.g., var specFile: File delegating to the underlying RegularFileProperty).
  plugin/src/functionalTest/kotlin/com/avsystem/justworks/gradle/JustworksPluginFunctionalTest.kt:1
• The functional test project’s build script configures specFile/packageName via assignment, but JustworksSpecConfiguration exposes these as RegularFileProperty/Property<String> vals, so the script should use .set(...) (or the plugin should provide DSL-friendly setters). As written, the TestKit build should fail during Kotlin script compilation.

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[Copilot]

The CodeBlock.of($$"Bearer ...") expression is not valid Kotlin syntax and will not compile. Build the generated string template using a normal Kotlin string (escaping $ as needed) and/or KotlinPoet format placeholders (e.g., %P) so the output becomes a valid Kotlin string literal like "Bearer ${tokenProvider}" (or function call if tokenProvider is meant to be a provider).

Suggested change

	CodeBlock.of("%S", "Bearer ${'$'}{tokenProvider}"),

[Copilot]

kotlin.time.Instant is not the same type used elsewhere in this repo for DATE_TIME (TypeMapping maps to kotlinx.datetime.Instant), and kotlin.time.Instant is not a generally available time API for parsing ISO instants. This will either fail to compile or generate code that doesn’t match the declared types; switch validation and emitted default expressions to kotlinx.datetime.Instant.parse(...) (and remove the incorrect import).

Suggested change

	import kotlinx.datetime.Instant

[Copilot]

kotlin.time.Instant is not the same type used elsewhere in this repo for DATE_TIME (TypeMapping maps to kotlinx.datetime.Instant), and kotlin.time.Instant is not a generally available time API for parsing ISO instants. This will either fail to compile or generate code that doesn’t match the declared types; switch validation and emitted default expressions to kotlinx.datetime.Instant.parse(...) (and remove the incorrect import).

[Copilot]

This emits else -> ... inside the loop, which can generate multiple else branches and/or statements after an else branch—both produce invalid Kotlin. Generate only condition branches in the loop, then add exactly one final else -> ... after the loop (either a single TODO with a summary, or a SerializationException), so the when expression is syntactically valid for any number of variants.

Suggested change

	}
	}
	// Add exactly one final else clause:
	// - if some variants have no unique fields: TODO with a summary
	// - otherwise: SerializationException for unknown variant
	val variantsWithoutUniqueFields = uniqueFieldsPerVariant
	.filter { it.second == null }
	.map { it.first }
	if (variantsWithoutUniqueFields.isNotEmpty()) {
	val summary = variantsWithoutUniqueFields.joinToString { "'$it'" }
	builder.addStatement(
	"else -> TODO(%S)",
	"No unique discriminating fields found for variants $summary of anyOf '$parentName' - manual selectDeserializer required",
	)
	} else {
	builder.addStatement(

[Copilot]

JsonContentPolymorphicSerializer<T>.selectDeserializer must override a method returning DeserializationStrategy<T> (for T = <sealed type>). Returning DeserializationStrategy<*> is not a valid override and should fail compilation. Change the return type to DeserializationStrategy<${schema.name}> (or an equivalent KotlinPoet TypeName) so the override matches the base signature.

[Copilot]

The return ParseResult.Success(...) inside the either {} block is a non-local return and will short-circuit the outer function, which makes the surrounding either { ... }.merge() expression inconsistent/ill-typed (and is very likely to not compile). Instead, make the success value the last expression of the either block (no return), and adjust the either/merge usage so the error and success types align (e.g., return Either<ParseResult, ParseResult> and merge, or avoid either here and use explicit early returns).

[Copilot]

Several imports appear unused in this file (e.g., NonEmptyList, Raise, RaiseAccumulate, ensure, ensureNotNull, recover). If the project enforces ktlint/detekt rules, these may fail linting; remove unused imports or use them as intended.

Suggested change

	import arrow.core.raise.ExperimentalRaiseAccumulateApi
	import arrow.core.raise.context.accumulate
	import arrow.core.raise.context.ensureNotNullOrAccumulate
	import arrow.core.raise.context.ensureOrAccumulate
	import arrow.core.raise.fold

[Copilot]

isPrimitiveOnly currently treats any schema with no properties/combinators as “primitive-only” and then hardcodes the alias target to String, which can silently generate incorrect models (e.g., empty-object schemas, free-form objects, numeric/string schemas with formats, etc.). Consider disabling this branch until the parser/model carries the underlying primitive/object type information, or extend SchemaModel to include the original schema kind so the alias target can be correct.

Suggested change

[Copilot]

isPrimitiveOnly currently treats any schema with no properties/combinators as “primitive-only” and then hardcodes the alias target to String, which can silently generate incorrect models (e.g., empty-object schemas, free-form objects, numeric/string schemas with formats, etc.). Consider disabling this branch until the parser/model carries the underlying primitive/object type information, or extend SchemaModel to include the original schema kind so the alias target can be correct.

Suggested change

	*
	* NOTE: This heuristic is intentionally disabled because it relied only on the absence
	* of properties/combinators and could misclassify empty-object or non-string schemas
	* as primitive-only. Once SchemaModel exposes the underlying schema kind/primitive
	* type, this method should be updated to use that information.
	*/
	private fun isPrimitiveOnly(schema: SchemaModel): Boolean {
	// Disabled until we have reliable primitive/object type information.
	return false
	}