Allow empty namespace to watch all namespaces.

[andersjanmyr]

Perhaps the default should be changed in operator-sdk up local, but I didn't include in this PR.

[CSdread]

we would love for this to be merged, this is a blocker for us as well @rithujohn191 @hasbro17 @theishshah

[spahl]

The idea with this function not allowing empty namespaces is to protect the user by default.

You can always skip using that function and pass an empty string to Watch directly. Would that work for both of your use cases?

I would also love to know more about the use cases to make sure we build the right thing here. Thanks

[CSdread]

My use case is building operators that can be created in any non kube-system namespace. We want to watch for the CRD to be created on any namespace so we can create the resource in the specified namespace. Right now we are passing empty string to the Watch directly but it would be nice to keep this method flexible as well. In my world we have very few use-cases for watching a single namespace.

[andersjanmyr]

@spahl The user will still be protected by default. Since you will explicitly have to set the variable to the empty string.

[EronWright]

@spahl are you able to merge this now?

[hasbro17]

@EronWright Yes I think we should be able to add this change in since it doesn't affect the default case.
/cc @fanminshi

[fanminshi]

lgtm