Narrowing down a closed question would invalidate existing answers – how to proceed?

Question

This question is inspired by the events on this question, but I think it is applicable more generally:

Suppose, somebody asks a question that is too broad and gets closed as such. However the closure does not happen quickly enough and some people post partial answers to the question. Now the asker responds to the closure by narrowing down the question in a way that would invalidate the existing answers. Alternatively, the question does not get closed in the first place and narrowed down quickly but only after partial answers were posted. How should we proceed?

I can think of the following alternatives and problems with them:

• Keep the question as it is (and possibley reopen it). This invalidates the existing answers, but one could consider this a risk that somebody enters who partially answers a too-broad question. The advantage is that the asker (who is usally a new user) does not get more frustrated by feeling to have done things wrong.
• Rollback to the broad question, keep the existing answers and leave the question closed; ask the asker to ask a new question. This is a possible source of frustration for the asker and the answerers.
• Edit the question to match the answers; ask the asker to ask a new question. Less frustration for the answerers than the above, but only possible if a question can be found that matches all existing answers.

Answer 1

In general, my feeling is that obsolescence of answers is a risk one takes when answering a too-broad question. We see the same sort of thing happening when people answer a question that has been poorly worded and then gets clarified. As such, I think that as a general principle, we should follow the intent of the OP, and let the answers shift or be deleted if needed.

As a counter to that, though, if the OP had a reasonable question that drew good answers, and then totally changed the question, I think that they should be rolled back and encouraged to ask a new question.

The particular question in this case I think is in a grey zone: it's way too broad, and the revised version wasn't really much better. As such, I think the roll-back was dubious: neither clearly right nor clearly wrong. My preference would be for the current question to remain closed and the OP to read a few more questions about their topic and try asking a new question from scratch.