[oas/reducer] does not support circular path references

[erunion]

If you have an operation schema that somewhere deep inside contains a $ref to another operation then when you reduce that operation it won't carry along the referenced operation, resulting in a corrupted schema.

For example:

Reducing GET /anything in this case will exclude POST /anything, resulting in a corrupted schema for GET /anything.

There is a broken and skipped test for this use case now in

oas/packages/oas/test/reducer/index.test.ts

Lines 185 to 195 in b373f99

	/**
	* @see RM-10597
	*/
	// eslint-disable-next-line vitest/no-disabled-tests
	it.skip('should preserve required data in a circular definition', async () => {
	const circular = new Oas(circularPathSchema as OASDocument);
	await circular.dereference();
	const reduced = reducer(circular.api as any, { paths: { '/anything': ['get'] } });
	expect(Object.keys(reduced.paths['/anything'])).toStrictEqual(['get', 'post']);
	});

.