fix(ruby): JSON-encode query params with content:application/json

[nbudin]

Fixes #24122.

Query parameters declared with content: { "application/json": ... } must be
serialized as JSON strings per the OpenAPI 3 spec. The Ruby client generator was ignoring this and emitting raw Ruby object representations instead.

The core model already handles this correctly: DefaultCodegen.fromParameter() sets queryIsJsonMimeType = true on any parameter whose content map has an application/json entry, and a test for this exists in DefaultCodegenTest#testQueryIsJsonMimeType. The Ruby api.mustache template was simply not using the flag.

(I used Claude Code to generate this PR, but I've hand-reviewed the code as well. Happy to remove the Claude attribution from the commit if desired!)

Mentioning the Ruby technical committee members: @cliffano @zlx @autopp

Changes

• api.mustache (ruby-client): branch on {{#queryIsJsonMimeType}} for both required and optional query params, calling .to_json instead of passing the value (or calling build_collection_param) directly
• Updated three echo_api Ruby samples (faraday, httpx, typhoeus) to reflect the corrected output
• Added RubyClientCodegenTest#testQueryParamJsonSerializationSetsQueryIsJsonMimeType to assert the flag propagates correctly through the Ruby codegen path

PR checklist

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---

Summary by cubic

JSON-encode Ruby client query parameters defined with content: application/json so they are sent as JSON strings, not Ruby object literals. Aligns with OpenAPI 3 and fixes #24122.

• Bug Fixes
  • In ruby-client/api.mustache, use queryIsJsonMimeType for required and optional query params and call .to_json; fallback keeps existing behavior.
  • Regenerated echo_api samples for ruby-faraday, ruby-httpx, and ruby-typhoeus; in ruby-httpx, object refs use @api_client.object_to_hash(...).to_json.
  • Added RubyClientCodegenTest#testQueryParamJsonSerializationSetsQueryIsJsonMimeType to assert flag propagation for content: application/json params.

^{Written for commit 69196ff. Summary will update on new commits.}

[cubic-dev-ai]

1 issue found across 5 files

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[wing328]

@nbudin thanks for the contribution. Have you tested the fix in your production environment to confirm the fix is working as expected?

[nbudin]

Hi @wing328! I haven't tested it in a production environment, but I have tested it locally on my machine by building a JAR with the changes, regenerating my Ruby client, and running my test script with the regenerated client, disabling the workarounds I'd been doing locally. I can confirm that with the regenerated client, my workarounds are no longer necessary and the query params are correctly encoded as JSON.

If you'd like me to try running it in production as well, I can discuss with my team and get back to you.

[wing328]

👌

let's give it a try

thanks for your contribution.