Prevent the deletion of data-lake variables when an input widget is removed

[ArturoManzoli]

Fixes #1711

[ES-Alexander]

Seems to be working as expected - nice! :-)

It's probably worth adding deletion capabilities to the data lake variable monitor (so there's at least some way of deleting variables), but that seems potentially out of scope for this PR. @rafaellehmkuhl thoughts on this? It seems somewhat relevant to the changes I suggested over here.

I suppose longer term it would be nice if we could detect whether a variable is being used anywhere else, and delete it automatically when the last reference to it is removed (like garbage collection in a programming language), but I don't expect we have such tight knowledge over everywhere each variable is used at the moment, or a reference count 🤷‍♂️

[rafaellehmkuhl]

Seems to be working as expected - nice! :-)

It's probably worth adding deletion capabilities to the data lake variable monitor (so there's at least some way of deleting variables), but that seems potentially out of scope for this PR. @rafaellehmkuhl thoughts on this? It seems somewhat relevant to the changes I suggested over here.

I suppose longer term it would be nice if we could detect whether a variable is being used anywhere else, and delete it automatically when the last reference to it is removed (like garbage collection in a programming language), but I don't expect we have such tight knowledge over everywhere each variable is used at the moment, or a reference count 🤷‍♂️

It's something we want to have, yes, but it needs the link to source and garbage collection, as you said.
I'm working on something similar for #1642.

[rafaellehmkuhl]

It's not showing the selected variable for an existing input widget.

[rafaellehmkuhl]

It's not showing the selected variable for an existing input widget.

Nevermind. Cleaning the cache solved the problem.