Auto generated model for write operation

[tadelesh]

When using typespec-autorest emitter, it seems the emitter will auto split a model into read model and update model if any properties has only read visibility. This seems to be a discrepancy between the swagger and the tsp which will cause breaking change. I wonder if it is by design?
e.g.: tsp: https://github.com/Azure/azure-rest-api-specs/blob/9ab4f198f6fe5a803e092919168fb1053ce67260/specification/elasticsan/ElasticSan.Management/models.tsp#L276 swagger: https://github.com/Azure/azure-rest-api-specs/blob/9ab4f198f6fe5a803e092919168fb1053ce67260/specification/elasticsan/resource-manager/Microsoft.ElasticSan/stable/2023-01-01/elasticsan.json#L2279

[markcowl]

This is by design as far as the template is concerned. There is q workaround for brownfield APIs to use the 'parameterVisibility' decorator for the operation, set to no visibility, if the entire resource is used as the PATCH input. This would be used in conjunction with the ArmCustomPatch* templates, or a lower level representation. e.g. this playground

Meanwhile, progress on a new template is blocked by this design issue: https://github.com/Azure/typespec-azure-pr/issues/3413