[numbata]

Summary

Array parameters with an array default, like type: [String], default: %w[8.8.8.8 8.8.4.4], now document that default on the array itself. Previously the whole list was placed under items, so Swagger tools showed a nested array and the schema was invalid. Scalar defaults keep their current placement.

Root cause

ParseParams#parse_array_item copied default into items for every array param, while the array-level default was skipped. An Array value is therefore never valid there (Swagger 2.0 requires items.default to be a single item value). Body params go through the same method and MoveParams only copied minItems/maxItems onto the array property, so the fix covers query, formData and body.

Drawbacks

Output changes for anyone with an Array default on an array param; consumers reading items.default for it will no longer find it.

Not covered

Defaults that are not plain values are unchanged and still go through the scalar path: a lambda default (default: -> { %w[a b] }) still emits items.default: {}, and default: false on a boolean array is still omitted. Both behave this way on master and are separate from where an Array default is placed.

Alternatives considered

Moving every default to the array level was rejected: #650 intentionally documents scalar defaults in items, and its specs pin that.

Closes #950

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Danger Report

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🟢 Approval recommended

No active review issues remain, and the change includes targeted parsing and parameter-move updates with regression coverage for both query and body array defaults.

No open issues 🎉

What changed in this PR

This pull request fixes Swagger 2.0 documentation for array-valued defaults by placing array defaults on the array schema rather than within items, while preserving scalar item-default behavior.

Changes:

• Stores array defaults on the parsed array parameter.
• Preserves array defaults when moving body parameters into schema properties.
• Adds regression coverage for query and body parameters.
• Documents the fix in the changelog.

File	Description
spec/​issues/​950_array_default_spec.rb	Verifies correct array-default output for query and body parameters.
lib/​grape-swagger/​doc_methods/​parse_params.rb	Distinguishes array defaults from scalar item defaults during parsing.
lib/​grape-swagger/​doc_methods/​move_params.rb	Preserves array-level defaults when converting body parameters into schema properties.
CHANGELOG.md	Documents the array-default placement fix.

_{Review effort: Lite}