the typahead approach seems like it'd work very well for our use-case.

Yeah, I agree with Evan. Trying to be 'magical' here just ends up frustrating as many users as it helps. I would always have to orient myself before doing a search, and then make the decision manually to search in global or local scope. Amazon has this interface and I think it's quite terrible. I always have to look to see where I am, make a decision to change whether I'm searching globally or per department, then take the action. I do, though, think the search experience right now could use some deeper thinking.

In https://phabricator.wikimedia.org/T76273#839187, @tgr wrote:

at the very least, the filter should be set when I am in one of the subareas of Phabricator. I.e. when I am in Maniphest (looking at a bug), the search should be limited to bugs; when I am in Diffusion, the search should be limited to commits.

Compare how e.g. Github works: when you are in a repo, the search box has a little "This repository" tag in it (which can be cleared by backspace) which limits the search to the current repo. Something similar could be done in Phabricator with the applications: when you are e.g. in Maniphest, show a little "Tasks" prefix which can be removed, and if it is not removed, the quicksearch should send you to the Maniphest search form (which has different controls, so filtering is not the only reason why it is far superior to the general search form) instead of the generic search form.

We had that, almost exactly:

We ... made search automatically contextual, so search from Maniphest meant "Search Maniphest Tasks".

It didn't work very well in this application. There are a lot more contexts and cross-context searches than on GitHub.

I have fiddled a bit with this, and I've got a few implementation questions.

I have roughly added a 'search typeahead' as PhabricatorTypeaheadResult:

$results[] = id(new PhabricatorTypeaheadResult())
    ->setName($raw_query) //'Search for '.$raw_query.' in Maniphest')
    ->setURI('/maniphest/query')
    ->setPHID($raw_query)
    ->setPriorityString($raw_query)
    ->setDisplayName('Maniphest Advanced Search')
    ->setDisplayType('Search for '.$raw_query)
    ->setImageURI(null)
    ->setPriorityType('apps')
    ->setImageSprite('phabricator-search-icon sprite-apps-large apps-maniphest-dark-large');

in PhabricatorApplicationDatasource::loadResults(), as a temporary test. This works to show the result, but already has two issues:

• the PHID has to be different for every result, or the javascript side will completely ignore the changed result
• the suggestion now disappears and reappears every time the user types something, which is confusing....

Adding the suggestion on the Javascript side might result in a better user experience in the end, but my Javascript-fu is even weaker than my PHP-fu ;-)

I haven't yet figured out:

• How to hook the typeahead up to Maniphest's advanced search, as 'fulltext' cannot be passed as GET parameter.
• How to only show this typeahead when we are currently viewing the Maniphest application

but these might actually also be easier from a Javascript perspective...

This is what the result looks like: