Inventory update will re-default max_unit

[Dan Smith]

If you have an existing inventory and you just update something like total or reserved, and do not provide max_unit, placement will re-default max_unit to MAX_INT instead of keeping the value that is currently set. I'm sure this was not intentional and means that if we update another field, the max_unit will become very large and surely not what the user intends.

[sean mooney (sean-k-mooney)]

semanticly invetory update is a http PUT https://docs.openstack.org/api-ref/placement/#update-resource-provider-inventory

so it shoudl only accpet full not partial objects so i think the correct behavior would be do do the following.

in a new micro version make partial updates a 400 and support patch for partial updates if that is desired.
patch should only mutate the filed that are present in the request and not modify the other values

i agree that its valid for post to support optional filed and have default this i hydrate server side but its not valid IMO for put to do that.

this api currently use PUT for both create and update and i think the optionallty ws intended for the create path which normlaly would use POST

the same issue seam to be present on

https://docs.openstack.org/api-ref/placement/#update-resource-provider-inventories

im not sure who this is handed in

https://docs.openstack.org/api-ref/placement/#update-resource-provider
with regards to parent_provider_uuid