gh-15545: Rank exact and prefix URL bar action matches above fuzzy ones (gh-15546)

src/zen/tests/ub-actions/browser_ub_actions_search.js

@@ -5,6 +5,8 @@
 
 ChromeUtils.defineESModuleGetters(this, {
   globalActions: "resource:///modules/ZenUBGlobalActions.sys.mjs",
+  SessionStore: "resource:///modules/sessionstore/SessionStore.sys.mjs",
+  TabStateFlusher: "resource:///modules/sessionstore/TabStateFlusher.sys.mjs",
   UrlbarTestUtils: "resource://testing-common/UrlbarTestUtils.sys.mjs",
 });
 
@@ -37,3 +39,29 @@ add_task(async function test_Ub_Actions_Search() {
     );
   }
 });
+
+add_task(async function test_Ub_Actions_Exact_Match_Ranks_First() {
+  // With a closed tab in history, "Reopen Closed Tab" is available too, and it
+  // contains "close tab". The exact label must still be the first action.
+  const tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "https://example.com"
+  );
+  await TabStateFlusher.flush(tab.linkedBrowser);
+  BrowserTestUtils.removeTab(tab);
+  await TestUtils.waitForCondition(
+    () => SessionStore.getClosedTabCount(window) > 0,
+    "Waiting for the closed tab to be recorded"
+  );
+
+  const closeTab = globalActions.find(a => a.command === "cmd_close");
+  await UrlbarTestUtils.promiseAutocompleteResultPopup({
+    window,
+    waitForFocus,
+    value: closeTab.label,
+  });
+  let { result } = await UrlbarTestUtils.getRowAt(window, 1);
+  Assert.equal(result.providerName, "ZenUrlbarProviderGlobalActions");
+  Assert.equal(result.payload.title, closeTab.label);
+  SessionStore.forgetClosedTab(window, 0);
+});

src/zen/urlbar/ZenUBActionsProvider.sys.mjs

@@ -18,6 +18,13 @@ const MAX_RECENT_ACTIONS = 5;
 const MINIMUM_QUERY_SCORE = 92;
 const MINIMUM_PREFIXED_QUERY_SCORE = 30;
 
+// Exact and prefix matches must outrank any fuzzy match. The fuzzy score grows
+// quadratically with a run of consecutive matches, so a longer label that merely
+// contains the query ("Reopen Closed Tab" for "close tab") could beat the label
+// that is exactly the query.
+const EXACT_MATCH_SCORE = 1_000_000;
+const PREFIX_MATCH_SCORE = 100_000;
+
 ChromeUtils.defineESModuleGetters(lazy, {
   UrlbarResult: "chrome://browser/content/urlbar/UrlbarResult.mjs",
   BrowserWindowTracker: "resource:///modules/BrowserWindowTracker.sys.mjs",
@@ -298,11 +305,11 @@ export class ZenUrlbarProviderGlobalActions extends UrlbarProvider {
     }
     // 1. Exact match gets the highest score.
     if (targetLower === queryLower) {
-      return 200;
+      return EXACT_MATCH_SCORE;
     }
     // 2. Exact prefix matches are heavily prioritized.
     if (targetLower.startsWith(queryLower)) {
-      return 100 + queryLen;
+      return PREFIX_MATCH_SCORE + queryLen;
     }
     let score = 0;
     let queryIndex = 0;