response-write-only-property-enum-value-added

What this check detects

`writeOnly` marks a property that clients send in requests but the server never returns in responses. So a `writeOnly` property inside a response schema is documentation of a field that is not actually sent back.

That is why adding an enum value to it is informational: the value can never reach a client, so no client can break on it. The same change on an ordinary response property is breaking, because the server may then return a value the client was not written to handle.

Example

The "legacy" value is added to a write-only property, which the server does not return, so no client can receive it.

Change its severity

oasdiff reports response-write-only-property-enum-value-added as informational, so it does not fail CI. To treat it as a warning or an error under your own compatibility policy, or to turn it off, set its level in a severity-levels file:

Put one rule per line; the level can be err, warn, or info, or none to disable the check entirely:

# severity.txt
response-write-only-property-enum-value-added err

Then pass it to oasdiff:

oasdiff changelog base.yaml revision.yaml --severity-levels severity.txt