The question had been closed as unconstructive, but it looked okay to me, so I cast a reopen vote. But then I thought, "this is a pretty basic question, I bet it's been asked already" and quickly found a near-perfect duplicate, almost down to the letter of the original question.
Supposing I had found the duplicate before casting my reopen vote, what is the proper course of action here? The possible course seems to be one of these:
- Add a comment pointing to the dupe and do nothing else; or
- Cast a re-open vote and then try to check back later and if it's been re-opened, cast a close-as-dupe vote; or
- Flag a moderator saying the question should be closed as duplicate, not unconstructive.
Following #1 we do lose a signpost to the original if this question is later deleted. Following #2 requires some extra attention and is not fool-proof. Following #3 adds work for a moderator that may not be worth it.