Set `buffer-invisibility-spec' to `nil' (a list) if it is just `t'
before inserting any body parts, otherwise removing items from
`buffer-invisibility-spec' (which is what
`notmuch-show-headers-visible' and `notmuch-show-message-visible' do)
is a no-op and has no effect. This caused threads with only matching
messages to have those messages hidden initially because
`buffer-invisibility-spec' stayed `t'.
projects / notmuch / commit