[BUG] [typescript-fetch] generated API references undeclared function objectToJSON

[luketudge]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

With a schema that contains an object as a property, generation for typescript-fetch produces an invalid client that contains a reference to an undeclared function objectToJSON.

openapi-generator version

latest (via docker hub)

OpenAPI declaration file content or url

See reprex at https://github.com/luketudge/openapi-reprex

Generation Details

docker run --rm \
    -v "${PWD}:/local" \
    openapitools/openapi-generator-cli generate \
    -i /local/openapi.json \
    -g typescript-fetch \
    -c /local/openapi_gen_config_typescript.json \
    -o /local/typescript

Steps to reproduce

https://github.com/luketudge/openapi-reprex

Related issues/PRs

Looks like a regression of #19280 but in a special case. Whereas the very similar bug reported there occurs for a schema in which the top-level item is declared as type 'object', the bug here is the same thing, but with a property that is declared as type object.

Suggest a fix

I'm looking into it. Not sure yet.

[luketudge]

Update: If I use openapitools/openapi-generator-cli:v7.14.0 the bug is absent. Seems to appear in v7.15.0 only.

[luketudge]

Ah, now I am seeing #21542 in which a fix for this was reverted. Would explain why this looks like a regression. I will try to look into and understand the reason for the revert.