existing views don't cope with a change to plugins in Views data

This came up as the daily bugsmash target. Wonder if the summary can be updated with clearer steps to reproduce to verify if still an issue.

There'd be 2 ways to reproduce this:

1. Artificially change the plugin on a Views field in Views data, and check that a view using that field doesn't pick up on it
2. Get an entity type with code-based bundles, and use the patch mentioned in the IS.

I'm not sure which is easier -- are there any examples of code-based bundles in core or contrib?

> 1. Artificially change the plugin on a Views field in Views data, and check that a view using that field doesn't pick up on it

On reflection, this is probably easier.

1. Make a view with a field, say on the node title
2. Create and enable a custom module which:
-- has a Views field handler plugin which always outputs 'banana'
-- implements view data alter hook which sets this plugin for the node title field
3. Existing view should now show 'banana', but it still uses the original plugin