Improve error messages when trying to use alpha featuers without enablement

CHANGELOG.md

@@ -1,3 +1,4 @@
+- Improve error messages when using alpha features without being in the alpha program (#4354)
 - Fixes bug where resumable uploads were not setting custom metadata on upload (#3398).
 - Fixes bug where GCS metadataUpdate cloud functions were triggered in incorrect situations (#3398).
 - Fixes bug where quoted escape sequences in .env files were incompletely unescaped. (#4270)

src/deploy/functions/prepare.ts

@@ -10,7 +10,7 @@ import * as validate from "./validate";
 import * as ensure from "./ensure";
 import { Options } from "../../options";
 import { functionMatchesAnyGroup, getFilterGroups } from "./functionsDeployHelper";
-import { logBullet } from "../../utils";
+import { logBullet, logLabeledError } from "../../utils";
 import { getFunctionsConfig, prepareFunctionsUpload } from "./prepareFunctionsUpload";
 import { promptForFailurePolicies, promptForMinInstances } from "./prompts";
 import { needProjectId, needProjectNumber } from "../../projectUtils";
@@ -20,6 +20,7 @@ import { ensureTriggerRegions } from "./triggerRegionHelper";
 import { ensureServiceAgentRoles } from "./checkIam";
 import { FirebaseError } from "../../error";
 import { normalizeAndValidate } from "../../functions/projectConfig";
+import { previews } from "../../previews";
 
 function hasUserConfig(config: Record<string, unknown>): boolean {
   // "firebase" key is always going to exist in runtime config.
@@ -127,16 +128,27 @@ export async function prepare(
         " directory for uploading..."
     );
   }
+  if (backend.someEndpoint(wantBackend, (e) => e.platform === "gcfv2")) {
+    if (!previews.functionsv2) {
+      throw new FirebaseError(
+        "This version of firebase-tools does not support Google Cloud " +
+          "Functions gen 2\n" +
+          "If Cloud Functions for Firebase gen 2 is still in alpha, sign up " +
+          "for the alpha program at " +
+          "https://services.google.com/fb/forms/firebasealphaprogram/\n" +
+          "If Cloud Functions for Firebase gen 2 is in beta, get the latest " +
+          "version of Firebse Tools with `npm i -g firebase-tools@latest`"
+      );
+    }
+    context.functionsSourceV2 = await prepareFunctionsUpload(sourceDir, context.config);
+  }
   if (backend.someEndpoint(wantBackend, (e) => e.platform === "gcfv1")) {
     context.functionsSourceV1 = await prepareFunctionsUpload(
       sourceDir,
       context.config,
       runtimeConfig
     );
   }
-  if (backend.someEndpoint(wantBackend, (e) => e.platform === "gcfv2")) {
-    context.functionsSourceV2 = await prepareFunctionsUpload(sourceDir, context.config);
-  }
 
   // Setup environment variables on each function.
   for (const endpoint of backend.allEndpoints(wantBackend)) {