MergePatchUpdate on Union Bodies

[Devon-White]

I recently updated to TypeSpec version 1.0.0 and i am finding that MergePatchUpdate only allows you to pass a model.

In the past I could do something like:

@patch update(
...SIPEndpointID,
 ...FabricSubscriberID,
 @body body: SubscriberSipEndpointUpdateRequest): {

I however can set the implicitOptinonality to get the legacy behavior:

@patch(#{ implicitOptionality: true }) update(
...SIPEndpointID,
 ...FabricSubscriberID,
 @body body: SubscriberSipEndpointUpdateRequest): {

Should MergePatchUpdate also be able to take a union of models to behave more like the legacy approach or should i always just use implicitOptionality in this case?

[timotheeguerin]

hhm yeah, this might be a bit of a limitation of the templates which needs to be of a specific type today.

How does your service behave with merge patch when changing to a different union variant? does it drop all the previous properties?