Track outcomes of querying FFs with getValue

src/feature-flags.test.ts

@@ -92,6 +92,31 @@ test(`Feature flags are requested in GHEC-DR`, async (t) => {
   });
 });
 
+test("Queried feature flags are recorded", async (t) => {
+  await withTmpDir(async (tmpDir) => {
+    const loggedMessages = [];
+    const features = setUpFeatureFlagTests(
+      tmpDir,
+      getRecordingLogger(loggedMessages),
+      { type: GitHubVariant.DOTCOM },
+    );
+
+    mockFeatureFlagApiEndpoint(200, initializeFeatures(true));
+
+    // No features should have been queried initially.
+    t.is(Object.keys(features.getQueriedFeatures()).length, 0);
+
+    // Query all features.
+    const allFeatures = Object.values(Feature);
+    for (const feature of allFeatures) {
+      await getFeatureIncludingCodeQlIfRequired(features, feature);
+    }
+
+    // All features should have a been queried.
+    t.is(Object.keys(features.getQueriedFeatures()).length, allFeatures.length);
+  });
+});
+
 test("API response missing and features use default value", async (t) => {
   await withTmpDir(async (tmpDir) => {
     const loggedMessages: LoggedMessage[] = [];
@@ -562,7 +587,7 @@ function setUpFeatureFlagTests(
   tmpDir: string,
   logger = getRunnerLogger(true),
   gitHubVersion = { type: GitHubVariant.DOTCOM } as util.GitHubVersion,
-): FeatureEnablement {
+): Features {
   setupActionsVars(tmpDir, tmpDir);
 
   return new Features(gitHubVersion, testRepositoryNwo, tmpDir, logger);

src/feature-flags.ts

@@ -345,6 +345,14 @@ export interface FeatureEnablement {
  */
 type GitHubFeatureFlagsApiResponse = Partial<Record<Feature, boolean>>;
 
+// Even though we are currently only tracking the value of queried features, we use an object
+// here rather than just a boolean to keep open the possibility of also tracking the reason
+// for why a particular value was resolved (i.e. because of an environment variable or API result)
+// in the future.
+export interface QueriedFeatureStatus {
+  value: boolean;
+}
+
 export const FEATURE_FLAGS_FILE_NAME = "cached-feature-flags.json";
 
 /**
@@ -355,6 +363,9 @@ export const FEATURE_FLAGS_FILE_NAME = "cached-feature-flags.json";
 export class Features implements FeatureEnablement {
   private gitHubFeatureFlags: GitHubFeatureFlags;
 
+  // Tracks features that have been queried at some point and the outcome.
+  private queriedFeatures: Partial<Record<Feature, QueriedFeatureStatus>> = {};
+
   constructor(
     gitHubVersion: util.GitHubVersion,
     repositoryNwo: RepositoryNwo,
@@ -369,6 +380,11 @@ export class Features implements FeatureEnablement {
     );
   }
 
+  /** Gets a record of features that were queried and the corresponding outcomes. */
+  public getQueriedFeatures() {
+    return this.queriedFeatures;
+  }
+
   async getDefaultCliVersion(
     variant: util.GitHubVariant,
   ): Promise<CodeQLDefaultVersionInfo> {
@@ -388,6 +404,15 @@ export class Features implements FeatureEnablement {
    * @throws if a `minimumVersion` is specified for the feature, and `codeql` is not provided.
    */
   async getValue(feature: Feature, codeql?: CodeQL): Promise<boolean> {
+    const value = await this.getValueInternal(feature, codeql);
+    this.queriedFeatures[feature] = { value };
+    return value;
+  }
+
+  private async getValueInternal(
+    feature: Feature,
+    codeql?: CodeQL,
+  ): Promise<boolean> {
     // Narrow the type to FeatureConfig to avoid type errors. To avoid unsafe use of `as`, we
     // check that the required properties exist using `satisfies`.
     const config = featureConfig[