Merino Sponsored/Non-Sponsored results have extra keywords suggested

[data-sync-user]

See also on bugzilla.

Compared to RemoteSettings counterparts, Firefox showed extra keywords in the title of the Merino suggestions.

┆Issue is synchronized with this Jira Bug
┆Epic: merino-nightly-test

[data-sync-user]

➤ Nan Jiang commented:

{
"block_id": 59,
"full_keyword": "amazon prime video",
"title": "Amazon.com - Official Site",
"url": "https://www.amazon.com/?tag=admarketus-20&ref=pd_sl_a318361095US59%YYYYMMDDHH%",
...
"score": 0.2
}For context, this is what Firefox received from Merino with the query “am“.

[data-sync-user]

➤ Michael Cooper commented:

Merino determines the full keyword as the longest search term that has the same suggestion (

merino/merino-adm/src/remote_settings/mod.rs

Lines 160 to 165 in 1a98c7e

	let full_keyword = adm_suggestion
	.keywords
	.iter()
	.max_by_key(|kw| kw.len())
	.expect("No keywords?")
	.clone();

).

Firefox uses a more complicated algorithm ( https://searchfox.org/mozilla-central/rev/a48e21143960b383004afa9ff9411c5cf6d5a958/browser/components/urlbar/UrlbarQuickSuggest.jsm#167-195 ) that aims to complete the current word, but not add anymore.

Merino’s current goal was to be the same as the existing Suggest implementation, and it is not doing that. It would be reasonable to change Merino to match Firefox’s implementation.