Support determining Dotcom CLI version from feature flags

src/feature-flags.test.ts

@@ -1,8 +1,9 @@
 import * as fs from "fs";
 import * as path from "path";
 
-import test from "ava";
+import test, { ExecutionContext } from "ava";
 
+import * as defaults from "./defaults.json"; // Referenced from codeql-action-sync-tool!
 import {
   Feature,
   featureConfig,
@@ -371,7 +372,61 @@ test("Environment variable can override feature flag cache", async (t) => {
   });
 });
 
-function assertAllFeaturesUndefinedInApi(t, loggedMessages: LoggedMessage[]) {
+for (const variant of [GitHubVariant.GHAE, GitHubVariant.GHES]) {
+  test(`selects CLI from defaults.json on ${GitHubVariant[variant]}`, async (t) => {
+    await withTmpDir(async (tmpDir) => {
+      const features = setUpFeatureFlagTests(tmpDir);
+      t.deepEqual(await features.getDefaultCliVersion(variant), {
+        cliVersion: defaults.cliVersion,
+        tagName: defaults.bundleVersion,
+        variant,
+      });
+    });
+  });
+}
+
+test("selects CLI v2.12.1 on Dotcom when feature flags enable v2.12.0 and v2.12.1", async (t) => {
+  await withTmpDir(async (tmpDir) => {
+    const featureEnablement = setUpFeatureFlagTests(tmpDir);
+    const expectedFeatureEnablement = initializeFeatures(true);
+    expectedFeatureEnablement["default_codeql_version_2_12_0_enabled"] = true;
+    expectedFeatureEnablement["default_codeql_version_2_12_1_enabled"] = true;
+    expectedFeatureEnablement["default_codeql_version_2_12_2_enabled"] = false;
+    expectedFeatureEnablement["default_codeql_version_2_12_3_enabled"] = false;
+    expectedFeatureEnablement["default_codeql_version_2_12_4_enabled"] = false;
+    expectedFeatureEnablement["default_codeql_version_2_12_5_enabled"] = false;
+    mockFeatureFlagApiEndpoint(200, expectedFeatureEnablement);
+
+    t.deepEqual(
+      await featureEnablement.getDefaultCliVersion(GitHubVariant.DOTCOM),
+      {
+        cliVersion: "2.12.1",
+        variant: GitHubVariant.DOTCOM,
+      }
+    );
+  });
+});
+
+test(`selects CLI v2.11.6 on Dotcom when no default version feature flags are enabled`, async (t) => {
+  await withTmpDir(async (tmpDir) => {
+    const featureEnablement = setUpFeatureFlagTests(tmpDir);
+    const expectedFeatureEnablement = initializeFeatures(true);
+    mockFeatureFlagApiEndpoint(200, expectedFeatureEnablement);
+
+    t.deepEqual(
+      await featureEnablement.getDefaultCliVersion(GitHubVariant.DOTCOM),
+      {
+        cliVersion: "2.11.6",
+        variant: GitHubVariant.DOTCOM,
+      }
+    );
+  });
+});
+
+function assertAllFeaturesUndefinedInApi(
+  t: ExecutionContext<unknown>,
+  loggedMessages: LoggedMessage[]
+) {
   for (const feature of Object.keys(featureConfig)) {
     t.assert(
       loggedMessages.find(

src/feature-flags.ts

@@ -3,11 +3,31 @@ import * as path from "path";
 
 import { getApiClient } from "./api-client";
 import { CodeQL } from "./codeql";
+import * as defaults from "./defaults.json"; // Referenced from codeql-action-sync-tool!
 import { Logger } from "./logging";
 import { RepositoryNwo } from "./repository";
 import * as util from "./util";
 
+const DEFAULT_VERSION_FEATURE_FLAG_PREFIX = "default_codeql_version_";
+const DEFAULT_VERSION_FEATURE_FLAG_SUFFIX = "_enabled";
+const MINIMUM_ENABLED_CODEQL_VERSION = "2.11.6";
+
+export type CodeQLDefaultVersionInfo =
+  | {
+      cliVersion: string;
+      variant: util.GitHubVariant.DOTCOM;
+    }
+  | {
+      cliVersion: string;
+      tagName: string;
+      variant: util.GitHubVariant.GHAE | util.GitHubVariant.GHES;
+    };
+
 export interface FeatureEnablement {
+  /** Gets the default version of the CodeQL tools. */
+  getDefaultCliVersion(
+    variant: util.GitHubVariant
+  ): Promise<CodeQLDefaultVersionInfo>;
   getValue(feature: Feature, codeql?: CodeQL): Promise<boolean>;
 }
 
@@ -91,6 +111,12 @@ export class Features implements FeatureEnablement {
     );
   }
 
+  async getDefaultCliVersion(
+    variant: util.GitHubVariant
+  ): Promise<CodeQLDefaultVersionInfo> {
+    return await this.gitHubFeatureFlags.getDefaultCliVersion(variant);
+  }
+
   /**
    *
    * @param feature The feature to check.
@@ -153,6 +179,68 @@ class GitHubFeatureFlags implements FeatureEnablement {
     /**/
   }
 
+  private static getCliVersionFromFeatureFlag(f: string): string | undefined {
+    if (
+      !f.startsWith(DEFAULT_VERSION_FEATURE_FLAG_PREFIX) ||
+      !f.endsWith(DEFAULT_VERSION_FEATURE_FLAG_SUFFIX)
+    ) {
+      return undefined;
+    }
+    return f
+      .substring(
+        DEFAULT_VERSION_FEATURE_FLAG_PREFIX.length,
+        f.length - DEFAULT_VERSION_FEATURE_FLAG_SUFFIX.length
+      )
+      .replace(/_/g, ".");
+  }
+
+  async getDefaultCliVersion(
+    variant: util.GitHubVariant
+  ): Promise<CodeQLDefaultVersionInfo> {
+    if (variant === util.GitHubVariant.DOTCOM) {
+      return {
+        cliVersion: await this.getDefaultDotcomCliVersion(),
+        variant,
+      };
+    }
+    return {
+      cliVersion: defaults.cliVersion,
+      tagName: defaults.bundleVersion,
+      variant,
+    };
+  }
+
+  async getDefaultDotcomCliVersion(): Promise<string> {
+    const response = await this.getAllFeatures();
+
+    const enabledFeatureFlagCliVersions = Object.entries(response)
+      .map(([f, isEnabled]) =>
+        isEnabled
+          ? GitHubFeatureFlags.getCliVersionFromFeatureFlag(f)
+          : undefined
+      )
+      .filter((f) => f !== undefined)
+      .map((f) => f as string);
+
+    if (enabledFeatureFlagCliVersions.length === 0) {
+      this.logger.debug(
+        "Feature flags do not specify a default CLI version. Falling back to CLI version " +
+          `${MINIMUM_ENABLED_CODEQL_VERSION}.`
+      );
+      return MINIMUM_ENABLED_CODEQL_VERSION;
+    }
+
+    const maxCliVersion = enabledFeatureFlagCliVersions.reduce(
+      (maxVersion, currentVersion) =>
+        currentVersion > maxVersion ? currentVersion : maxVersion,
+      enabledFeatureFlagCliVersions[0]
+    );
+    this.logger.debug(
+      `Derived default CLI version of ${maxCliVersion} from feature flags.`
+    );
+    return maxCliVersion;
+  }
+
   async getValue(feature: Feature): Promise<boolean> {
     const response = await this.getAllFeatures();
     if (response === undefined) {

src/testing-utils.ts

@@ -201,6 +201,9 @@ export function mockCodeQLVersion(version) {
  */
 export function createFeatures(enabledFeatures: Feature[]): FeatureEnablement {
   return {
+    getDefaultCliVersion: async () => {
+      throw new Error("not implemented");
+    },
     getValue: async (feature) => {
       return enabledFeatures.includes(feature);
     },

src/util.ts

@@ -19,6 +19,7 @@ import {
   parsePacksSpecification,
   prettyPrintPack,
 } from "./config-utils";
+import * as defaults from "./defaults.json"; // Referenced from codeql-action-sync-tool!
 import { Feature, FeatureEnablement } from "./feature-flags";
 import { KOTLIN_SWIFT_BYPASS, Language } from "./languages";
 import { Logger } from "./logging";
@@ -901,3 +902,44 @@ export function parseMatrixInput(
   }
   return JSON.parse(matrixInput);
 }
+
+/** Version information about a CodeQL bundle. */
+export interface CodeqlBundleVersionInfo {
+  /** Version number of the CLI contained within this bundle. */
+  cliVersion: string;
+  /** The name of the tag of the GitHub Release containing this bundle. */
+  tagName: string;
+  /**
+   * Version number of this bundle within the toolcache.
+   *
+   * For compatibility with previous runner images and toolcaches, consumers should fallback to
+   * looking up the `0.0.0-pre` version number within the toolcache if this version number is not
+   * found, where `pre` is the prerelease component of this version number.
+   */
+  toolcacheVersion: string;
+}
+
+function computeToolcacheVersion(cliVersion: string, tagName: string): string {
+  return `${cliVersion}-${tagName}`;
+}
+
+/**
+ * Gets version information about the CodeQL bundle which was current as of the release of this
+ * Action.
+ *
+ * This should be used in the following circumstances:
+ *
+ * - When running the Action on Enterprise instances.
+ * - When a user requests `tools: latest`.
+ * - When the Action is running on Dotcom and no default CodeQL version feature flags are enabled.
+ */
+export function getPinnedCodeqlVersion(): CodeqlBundleVersionInfo {
+  return {
+    cliVersion: defaults.cliVersion,
+    tagName: defaults.bundleVersion,
+    toolcacheVersion: computeToolcacheVersion(
+      defaults.cliVersion,
+      defaults.bundleVersion
+    ),
+  };
+}