Update manifest _create_diff.md

[Samze]

See https://github.com/cloudfoundry/cloud_controller_ng/blob/main/app/controllers/v3/space_manifests_controller.rb#L59C21-L59C28

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[stephanme]

I think POST /v3/spaces/:guid/manifest_diff should return 200 and not 201 as there is no resource created.

See also:

• https://v3-apidocs.cloudfoundry.org/version/3.199.0/#status-codes
• https://github.com/cloudfoundry/cloud_controller_ng/blob/main/docs/v3_style_guide.md#responses-1

[Samze]

While I agree, I don't know if changing this would break any clients that are relying on the current status code.

[stephanme]

POST /v3/spaces/:guid/manifest_diff is still marked as experimental.

If it doesn't break CLI v8, I would risk changing 201 into 200.

[Gerg]

From a certain perspective, the "manifest diff" resource is created. It's just not persisted anywhere. REST can be pretty liberal about what counts as a "resource".

The styleguide, divides POSTs into "Create Resource" case vs the "Trigger Action" case. Actions typically have "action" in the path and affect the runtime.

In the end, I don't care that much about the status code. 200 vs 201 probably doesn't make a material difference.

[sethboyles]

Regardless if we change this in the future, I think it makes sense to update the current docs.