Conditional experiment matching (#1661)

* PoC conditional experiment matching

* Add test case

* Fix broken test case

Author: jonathanKingston

injected/entry-points/integration.js

@@ -22,6 +22,18 @@ function generateConfig() {
         platform: {
             name: 'extension',
         },
+        currentCohorts: [
+            {
+                feature: 'ContentScopeExperiments',
+                subfeature: 'bloops',
+                cohort: 'control',
+            },
+            {
+                feature: 'ContentScopeExperiments',
+                subfeature: 'test',
+                cohort: 'treatment',
+            },
+        ],
         site: {
             domain: topLevelUrl.hostname,
             url: topLevelUrl.href,
@@ -97,6 +109,7 @@ async function initCode() {
         site: processedConfig.site,
         bundledConfig: processedConfig.bundledConfig,
         messagingConfig: processedConfig.messagingConfig,
+        currentCohorts: processedConfig.currentCohorts,
     });
 
     // mark this phase as loaded

injected/integration-test/pages.spec.js

@@ -37,6 +37,15 @@ test.describe('Test integration pages', () => {
         );
     });
 
+    test('Test infra with experiments', async ({ page }, testInfo) => {
+        await testPage(
+            page,
+            testInfo,
+            '/infra/pages/conditional-matching-experiments.html',
+            './integration-test/test-pages/infra/config/conditional-matching-experiments.json',
+        );
+    });
+
     test('Test infra fallback', async ({ page }, testInfo) => {
         await page.addInitScript(() => {
             // This ensures that our fallback code applies and so we simulate other platforms than Chromium.

injected/integration-test/test-pages/infra/config/conditional-matching-experiments.json

@@ -0,0 +1,85 @@
+{
+    "features": {
+      "contentScopeExperiments": {
+        "exceptions": [],
+        "state": "enabled",
+        "features": {
+          "bloops": {
+            "state": "enabled",
+            "rollout": {},
+            "cohorts": [
+              {
+                "name": "control",
+                "weight": 1
+              },
+              {
+                "name": "treatment",
+                "weight": 1
+              }
+            ]
+          },
+          "test": {
+            "state": "enabled",
+            "rollout": {},
+            "cohorts": [
+              {
+                "name": "control",
+                "weight": 1
+              },
+              {
+                "name": "treatment",
+                "weight": 1
+              }
+            ]
+          }
+        }
+      },
+      "apiManipulation": {
+        "state": "enabled",
+        "settings": {
+          "apiChanges": {
+            "Navigator.prototype.hardwareConcurrency": {
+              "type": "descriptor",
+              "getterValue": {
+                "type": "number",
+                "value": 100
+              }
+            }
+          },
+          "conditionalChanges": [
+            {
+              "condition": {
+                "experiment": {
+                  "experimentName": "bloops",
+                  "cohort": "treatment"
+                }
+              },
+              "patchSettings": [
+                {
+                  "op": "replace",
+                  "path": "/apiChanges/Navigator.prototype.hardwareConcurrency/getterValue/value",
+                  "value": 200
+                }
+              ]
+            },
+            {
+              "condition": {
+                "experiment": {
+                  "experimentName": "bloops",
+                  "cohort": "control"
+                }
+              },
+              "patchSettings": [
+                {
+                  "op": "replace",
+                  "path": "/apiChanges/Navigator.prototype.hardwareConcurrency/getterValue/value",
+                  "value": 300
+                }
+              ]
+            }
+          ]
+        }
+      },
+      "exceptions": []
+    }
+}

injected/integration-test/test-pages/infra/index.html

@@ -10,6 +10,7 @@
     <p><a href="../../index.html">[Home]</a></p>
     <ul>
         <li><a href="./pages/conditional-matching.html">Conditional matching</a> - <a href="./config/conditional-matching.json">Config</a></li>
+        <li><a href="./pages/conditional-matching-experiments.html">Conditional matching experiments</a> - <a href="./config/conditional-matching-experiments.json">Config</a></li>
     </ul>
 </body>
 </html>

injected/integration-test/test-pages/infra/pages/conditional-matching-experiments.html

@@ -0,0 +1,49 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width">
+  <title>Conditional Matching experiments</title>
+  <link rel="stylesheet" href="../../shared/style.css">
+</head>
+<body>
+    <script src="../../shared/utils.js"></script>
+    <p><a href="../index.html">[Infra]</a></p>
+
+    <p>This page verifies that APIs get modified when in an experiment. Ensure you're sending the following cohorts:
+        <code>
+        currentCohorts: [
+            {
+                "feature": "ContentScopeExperiments",
+                "subfeature": "bloops",
+                "cohort": "control",
+            },
+            {
+                "feature": "ContentScopeExperiments",
+                "subfeature": "test",
+                "cohort": "treatment",
+            },
+        ],
+        </code>
+    </p>
+
+    <script>
+        test('Conditional matching experiments', async () => {
+            const res = navigator.hardwareConcurrency;
+            // Either is valid here, but 100 is the default which would mean the experiment is not running
+            const expected  = res === 200 ? 200 : 300;
+            const results = [
+                {
+                    name: "APIs changing, expecting to always match",
+                    result: res,
+                    expected: expected,
+                }
+            ];
+            return results;
+        });
+
+        // eslint-disable-next-line no-undef
+        renderResults();
+    </script>
+</body>
+</html>

injected/src/config-feature.js

@@ -16,7 +16,18 @@ export default class ConfigFeature {
     /** @type {string} */
     name;
 
-    /** @type {{ debug?: boolean, desktopModeEnabled?: boolean, forcedZoomEnabled?: boolean, featureSettings?: Record<string, unknown>, assets?: import('./content-feature.js').AssetConfig | undefined, site: import('./content-feature.js').Site, messagingConfig?: import('@duckduckgo/messaging').MessagingConfig } | null} */
+    /**
+     * @type {{
+     *   debug?: boolean,
+     *   desktopModeEnabled?: boolean,
+     *   forcedZoomEnabled?: boolean,
+     *   featureSettings?: Record<string, unknown>,
+     *   assets?: import('./content-feature.js').AssetConfig | undefined,
+     *   site: import('./content-feature.js').Site,
+     *   messagingConfig?: import('@duckduckgo/messaging').MessagingConfig,
+     *   currentCohorts?: [{feature: string, cohort: string, subfeature: string}],
+     * } | null}
+     */
     #args;
 
     /**
@@ -95,6 +106,9 @@ export default class ConfigFeature {
      * @typedef {object} ConditionBlock
      * @property {string[] | string} [domain]
      * @property {object} [urlPattern]
+     * @property {object} [experiment]
+     * @property {string} [experiment.experimentName]
+     * @property {string} [experiment.cohort]
      */
 
     /**
@@ -121,6 +135,7 @@ export default class ConfigFeature {
         const conditionChecks = {
             domain: this._matchDomainConditional,
             urlPattern: this._matchUrlPatternConditional,
+            experiment: this._matchExperimentConditional,
         };
 
         for (const key in conditionBlock) {
@@ -152,6 +167,36 @@ export default class ConfigFeature {
         return true;
     }
 
+    /**
+     * Takes a condition block and returns true if the current experiment matches the experimentName and cohort.
+     * Expects:
+     * ```json
+     * {
+     *   "experiment": {
+     *      "experimentName": "experimentName",
+     *      "cohort": "cohort-name"
+     *    }
+     * }
+     * ```
+     * Where featureName "ContentScopeExperiments" has a subfeature "experimentName" and cohort "cohort-name"
+     * @param {ConditionBlock} conditionBlock
+     * @returns {boolean}
+     */
+    _matchExperimentConditional(conditionBlock) {
+        if (!conditionBlock.experiment) return false;
+        const experiment = conditionBlock.experiment;
+        if (!experiment.experimentName || !experiment.cohort) return false;
+        const currentCohorts = this.args?.currentCohorts;
+        if (!currentCohorts) return false;
+        return currentCohorts.some((cohort) => {
+            return (
+                cohort.feature === 'ContentScopeExperiments' &&
+                cohort.subfeature === experiment.experimentName &&
+                cohort.cohort === experiment.cohort
+            );
+        });
+    }
+
     /**
      * Takes a condtion block and returns true if the current url matches the urlPattern.
      * @param {ConditionBlock} conditionBlock