tor-browser

commit e692405da5787b7885238dd70fa07d1772e8c949
parent 0a13b56b7140c1e5577fe59f4d9ea160cf9931e6
Author: Nathan Barrett <nbarrett@mozilla.com>
Date:   Fri, 12 Dec 2025 16:00:48 +0000

Bug 2005622 - Fetch trainhop config during startup in PrefsFeed r=mconley,home-newtab-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D276087

Diffstat:
M
browser/extensions/newtab/lib/PrefsFeed.sys.mjs
 | 
20
++++++++++++--------
M
browser/extensions/newtab/test/unit/lib/PrefsFeed.test.js
 | 
23
+++++++++++++++++++++++

2 files changed, 35 insertions(+), 8 deletions(-)
diff --git a/browser/extensions/newtab/lib/PrefsFeed.sys.mjs b/browser/extensions/newtab/lib/PrefsFeed.sys.mjs
@@ -101,13 +101,13 @@ export class PrefsFeed {
   }
 
   /**
-   * Handler for when experiment data updates.
+   * Computes the trainhop config by processing all enrollments.
    * Supports two formats:
    * - Single payload: { type: "feature", payload: { "enabled": true, ... }}
    * - Multi-payload: { type: "multi-payload", payload: [{ type: "feature", payload: { "enabled": true, ... }}] }
    * Both formats output the same structure: { "feature": { "enabled": true, ... }}
    */
-  onTrainhopExperimentUpdated() {
+  _getTrainhopConfig() {
     const allEnrollments =
       lazy.NimbusFeatures.newtabTrainhop.getAllEnrollments() || [];
 
@@ -134,12 +134,6 @@ export class PrefsFeed {
       }
     });
 
-    // Combine all trainhop experiments keyed by type.
-    // Rules for duplicates:
-    // - Experiments take precedence over rollouts (this is expected).
-    // - If multiple experiments or multiple rollouts exist for the same type,
-    //   only the first is kept. This is nondeterministic and considered an error;
-    //   those experiments/rollouts should be relaunched.
     const valueObj = {};
     enrollmentsToProcess.reduce((accumulator, currentValue) => {
       if (currentValue?.value?.type) {
@@ -155,6 +149,15 @@ export class PrefsFeed {
       return accumulator;
     }, {});
 
+    return valueObj;
+  }
+
+  /**
+   * Handler for when experiment data updates.
+   */
+  onTrainhopExperimentUpdated() {
+    const valueObj = this._getTrainhopConfig();
+
     this.store.dispatch(
       ac.BroadcastToContent({
         type: at.PREF_CHANGED,
@@ -336,6 +339,7 @@ export class PrefsFeed {
       lazy.NimbusFeatures.newtabSmartShortcuts.getAllVariables() || {};
     values.widgetsConfig =
       lazy.NimbusFeatures.newtabWidgets.getAllVariables() || {};
+    values.trainhopConfig = this._getTrainhopConfig();
     this._setBoolPref(values, "logowordmark.alwaysVisible", false);
     this._setBoolPref(values, "feeds.section.topstories", false);
     this._setBoolPref(values, "discoverystream.enabled", false);
diff --git a/browser/extensions/newtab/test/unit/lib/PrefsFeed.test.js b/browser/extensions/newtab/test/unit/lib/PrefsFeed.test.js
@@ -90,6 +90,29 @@ describe("PrefsFeed", () => {
     const [{ data }] = feed.store.dispatch.firstCall.args;
     assert.deepEqual(data.featureConfig, { prefsButtonIcon: "icon-foo" });
   });
+  it("should dispatch PREFS_INITIAL_VALUES with trainhopConfig", () => {
+    const testObject = {
+      meta: { isRollout: false },
+      value: {
+        type: "testExperiment",
+        payload: { enabled: true },
+      },
+    };
+    sandbox
+      .stub(global.NimbusFeatures.newtabTrainhop, "getAllEnrollments")
+      .returns([testObject]);
+
+    feed.onAction({ type: at.INIT });
+
+    assert.equal(
+      feed.store.dispatch.firstCall.args[0].type,
+      at.PREFS_INITIAL_VALUES
+    );
+    const [{ data }] = feed.store.dispatch.firstCall.args;
+    assert.deepEqual(data.trainhopConfig, {
+      testExperiment: { enabled: true },
+    });
+  });
   it("should dispatch PREFS_INITIAL_VALUES with an empty object if no experiment is returned", () => {
     sandbox.stub(global.NimbusFeatures.newtab, "getAllVariables").returns(null);
     feed.onAction({ type: at.INIT });