Should datastore Key's be immutable?

[jgeewax]

This seems like a pain in the ass to deal with if they are:

entity = dataset.entity('Person')
entity.key(entity.key().name('name'))

versus

entity = dataset.entity('Person')
entity.key().name('name')

What do we really get by making a Key immutable?

A Query being immutable makes great sense - chaining things together is easy and you can "fork" a query into several different ones. But it's unlikely we'll need to fork a key...

[jgeewax]

Good thought from @proppy: Maybe we should make the Key class a subclass of tuple or list ...

[proppy]

I drafted some ideas in this gist:
https://gist.github.com/proppy/8718248

[dhermes]

I am working on this per the discussion in:
https://docs.google.com/document/d/1xKw8Tz6lfN5uOcv0my4uUgFSeDoRzwCLho2UGlBpqDU/edit

[dhermes]

Closing this to consolidate the work in #451.

The answer to the question is "Yes, keys should be immutable."