feat(ruby): let the caller omit an optional request body

[devin-ai-integration]

Description

Linear ticket: Refs

Ruby parity for IR request-body omittability (#17360 has merged, so this now targets main; alongside #17372 Java, #17370 Python, #17368 TS, #17373 C#, #17378 Go, #17380 PHP).

A referenced request body that the API does not mark required is now omittable by the caller when the new respectOptionalRequestBody option is on. Previously a bodyless Ruby call still sent {} with Content-Type: application/json — the Payabli over-refund shape, where the docs snippet looks bodyless but the SDK sends a body.

The option is off by default, so existing output is byte-identical (the respect-optional-request-body/no-custom-config seed output is identical to the previously committed root output for that fixture).

Changes Made

• respectOptionalRequestBody in BaseRubyCustomConfigSchema (Ruby's camelCase config convention), optional/off by default.
• SDK: when the flag is on and endpoint.requestBody is a reference with required === false, the generated body reference becomes params.empty? ? nil : Types::RefundRequest.new(params).to_h and the request is constructed with omit_content_type_without_body: true. Form-urlencoded bodies are excluded (their template always emits a form content type).
• internal/json/request.rb (templated): under the flag, Content-Type is added only when a body is present:

  sdk_headers = { "Accept" => "application/json" }
  sdk_headers["Content-Type"] = "application/json" unless @omit_content_type_without_body && @body.nil?

  With the flag off, the template renders exactly the previous unconditional hash — no new parameter, no new ivar.
• Dynamic snippets: bodyRequired === false + an absent/empty example body drops the body keyword arguments entirely (no dangling separator), via callOmitsRequestBody.
• IR pins bumped to 67.21.0 in all four ruby-v2 packages (dynamic-snippets @fern-api/dynamic-ir-sdk; base/model/sdk @fern-fern/ir-sdk) — see "Dependency pin" below.
• Seed: respect-optional-request-body fixture now generates two cases (no-custom-config, respect-optional-request-body). The fixture's request schema is a shared $ref used by multiple endpoints, so it stays a reference in the IR (fern ir shows refund -> type: reference, required: false, bulkRefund -> reference/false, requiredRefund -> reference/null), rather than being inlined and making the flag inert.
• Changelog entry under generators/ruby-v2/sdk/changes/unreleased/.

Dependency pin

@fern-api/dynamic-ir-sdk@67.21.0 / @fern-fern/ir-sdk@67.21.0 are the versions #17360 publishes, and the four ruby-v2 manifests now pin them explicitly — EndpointSnippetGenerator reads dynamic.BodyRequest.bodyRequired and the SDK generator reads HttpRequestBodyReference.required, neither of which exists in the previous pins (66.1.0 / 67.15.0), with no casts or suppressions.

Blocked on the IR release pipeline, not on this PR. @fern-fern/ir-sdk@67.21.0 is on npm.buildwithfern.com, but the dynamic-ir job of Release IR SDKs failed for the #17360 commit, so @fern-api/dynamic-ir-sdk@67.21.0 does not exist on npm (latest is 67.12.0) (run 31607788833):

npm error code E404
npm error 404 Not Found - PUT https://registry.npmjs.org/@fern-api%2fdynamic-ir-sdk - Not found
npm error 404  The requested resource '@fern-api/dynamic-ir-sdk@67.21.0' could not be found or you do not have permission to access it.

That job has been failing since 67.12.0 (the same failure is on the previous Release IR SDKs runs), which looks like the publish credential for that package rather than anything in the IR change. Until it publishes, pnpm install cannot resolve the pin, so pnpm-lock.yaml cannot be refreshed and every CI job fails at the frozen-lockfile install — as it does on the other stacked generator PRs that bumped to 67.21.0. tsc over ruby-dynamic-snippets and ruby-sdk against the new field definitions passes cleanly.

Testing

• Unit tests added/updated — generators/ruby-v2/dynamic-snippets/src/__test__/OptionalRequestBody.test.ts (35 tests pass in that package); ruby-sdk tests pass.

• Seed: pnpm seed test --generator ruby-sdk-v2 --skip-scripts --local → 150/150; only the new fixture output changed.

• Manual testing completed — wire capture of the generated SDK (Ruby 3.3 in Docker) against a local HTTP server that echoes the request line, headers and body:

  case	Content-Type	body
  flag on, bulk_refund no body	absent	none (no Content-Length)
  flag on, bulk_refund with body	application/json	{"amount":60}
  flag on, refund (path param only, no body)	absent	none
  flag on, refund (path param + body)	application/json	{"amount":60}
  flag on, required_refund (required body)	application/json	{} (unchanged)
  flag off, every case above	application/json	{} / {"amount":60} (unchanged)

Link to Devin session: https://app.devin.ai/sessions/a0178cce544c4a51ba568b0fc7c8b5fa

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[nitpickybot]

Reviewed the changes — everything looks good. No issues found.

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SDK Generation Benchmark Results

Comparing PR branch against median of 5 nightly run(s) on main (latest: 2026-08-13T04:34:37Z).

Full benchmark table (click to expand)

Generator	Spec	main (generator)	main (E2E)	PR (generator)	Delta
ruby-sdk-v2	square	106s (n=5)	147s (n=5)	88s	-18s (-17.0%)

main (generator): generator-only time via --skip-scripts (includes Docker image build, container startup, IR parsing, and code generation — this is the same Docker-based flow customers use via fern generate). main (E2E): full customer-observable time including build/test scripts (nightly baseline, informational). Delta is computed against generator-only baseline.
⚠️ = generation exited with a non-zero exit code (timing may not reflect a successful run).
Baseline from nightly runs on main (latest: 2026-08-13T04:34:37Z). Trigger benchmark-baseline to refresh.
Last updated: 2026-08-13 17:06 UTC