Support default value for array properties

[stmeissner]

Fixes #351

Summary

When a RAML property has an array type with a single-element default: value, the ramldoc language module generates invalid YAML — the array's default is rendered as a YAML block-sequence item spliced onto the same line as the default: key, which is not legal YAML.

Expected output

roles:
  type: array
  items:
    type: ChannelRoleEnum
  default: "InventorySupply"
  required: true

Root cause

In languages/ramldoc/src/main/kotlin/io/vrap/codegen/languages/ramldoc/extensions/VrapExtensions.kt, the Instance.toYaml() extension function handles ArrayInstance values by passing the raw List<Instance> to Jackson's YAMLMapper, which correctly serializes it as a YAML block sequence (e.g. - "InventorySupply"). The renderer call sites (e.g. RamlObjectTypeRenderer.kt, OasTypeRenderer.kt, RamlResourceRenderer.kt) then splice this directly after default: on a single source line, which is invalid for a sequence.

Fix

Unwrap single-element ArrayInstance defaults to their scalar value before serialization in toYaml(), so they render as a plain scalar (default: "InventorySupply") instead of a block sequence. Multi-element array defaults are a separate, currently unsupported case (no valid single-line representation exists in YAML for them) and are out of scope for this fix.

Affected files

• languages/ramldoc/src/main/kotlin/io/vrap/codegen/languages/ramldoc/extensions/VrapExtensions.kt
• languages/ramldoc/src/main/kotlin/io/vrap/codegen/languages/ramldoc/model/RamlObjectTypeRenderer.kt
• languages/ramldoc/src/main/kotlin/io/vrap/codegen/languages/ramldoc/model/RamlResourceRenderer.kt (query-param defaults, same pattern)

Test coverage

Added testArrayDefaultWithSingleElementRendersAsScalar in languages/ramldoc/src/test/kotlin/io/vrap/codegen/languages/ramldoc/TestCodeGenerator.kt, backed by fixture languages/ramldoc/src/test/resources/arraydefault.raml, asserting the generated output contains default: "InventorySupply" and not default: - "InventorySupply".

[Copilot]

Pull request overview

Fixes invalid YAML emitted by the ramldoc generator when rendering default: values for array-typed properties that contain a single default element.

Changes:

• Add a regression RAML fixture covering an array property with a single-element default.
• Add a generator test asserting the produced RAML contains default: "InventorySupply" and not the invalid default: - "InventorySupply".
• Update Instance.toYaml() to unwrap single-element ArrayInstance values before serialization.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
languages/ramldoc/src/test/resources/arraydefault.raml	Adds a minimal RAML spec fixture reproducing the single-item array default scenario.
languages/ramldoc/src/test/kotlin/io/vrap/codegen/languages/ramldoc/TestCodeGenerator.kt	Adds a regression test validating the generated output for array defaults.
languages/ramldoc/src/main/kotlin/io/vrap/codegen/languages/ramldoc/extensions/VrapExtensions.kt	Changes YAML serialization behavior to unwrap single-item arrays.

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[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated no new comments.

Suppressed comments (1)

languages/ramldoc/src/main/kotlin/io/vrap/codegen/languages/ramldoc/model/OasTypeRenderer.kt:251

• This changes an unused overload, so it cannot affect generated OpenAPI-backed types as described. All active callers use renderProperty(name: String, type: Schema<Any>, required: List<String>?) (for example, lines 127, 157, and 169), while this RAML-model overload has no caller; the active overload also never emits type.default. Update the active OAS rendering path if OAS support is intended, or remove this ineffective change from the PR's stated scope.

            |  default: ${property.type.default.toYaml(true)}""" else ""}${if (property.type?.isInlineType == true && property.type?.annotations != null) """