[FEATURE] Purge ignored messages from index

[Markus Weimar]

On Thu, 2018-11-22 16:49:56 -0400, David Bremner wrote:
> Notmuch new works very hard to not visit files that haven't
> changed. Changing this would have a big negative performance impact, afaik.

I see. I thought it might be possible to purge the entries without looking at any files by doing a cheap comparison of indexed file path against ignored patterns. If that’s not possible, I agree that ´new´ shouldn’t be slowed down for this edge case.

> I care less about the performance of reindex; also it already
> rescans all the relevant messages, so I guess the performance impact
> would not be that bad.

Makes sense to me. Short notes in the docs and config file to run ´reindex 'folder:<pattern>'´ after adding new ignore patterns would prevent any such confusion.

Take care,
Markus