BUGFIX: Check if Glean is initialized before dispatching toggle upload task

Checking inside the task had no meaning, because that would guarantee
the call to be executed _after_ the initialize task. That is the case,
because the initialize task is _always_ the first task to be executed by
the dispatcher regardless of any other previously dispatched tasks.

Author: brizental

glean/src/core/glean.ts

@@ -355,6 +355,19 @@ class Glean {
    * @param flag When true, enable metric collection.
    */
   static setUploadEnabled(flag: boolean): void {
+    if (!Context.initialized) {
+      log(
+        LOG_TAG,
+        [
+          "Changing upload enabled before Glean is initialized is not supported.\n",
+          "Pass the correct state into `Glean.initialize`.\n",
+          "See documentation at https://mozilla.github.io/glean/book/user/general-api.html#initializing-the-glean-sdk`"
+        ],
+        LoggingLevel.Error
+      );
+      return;
+    }
+
     if (!isBoolean(flag)) {
       log(
         LOG_TAG,
@@ -365,19 +378,6 @@ class Glean {
     }
 
     Context.dispatcher.launch(async () => {
-      if (!Context.initialized) {
-        log(
-          LOG_TAG,
-          [
-            "Changing upload enabled before Glean is initialized is not supported.\n",
-            "Pass the correct state into `Glean.initialize\n`.",
-            "See documentation at https://mozilla.github.io/glean/book/user/general-api.html#initializing-the-glean-sdk`"
-          ],
-          LoggingLevel.Error
-        );
-        return;
-      }
-
       if (Context.uploadEnabled !== flag) {
         if (flag) {
           await Glean.onUploadEnabled();

glean/tests/unit/core/glean.spec.ts

@@ -164,6 +164,14 @@ describe("Glean", function() {
     assert.strictEqual(spy.callCount, 1);
   });
 
+  it("attempting to change upload status prior to initialize is a no-op", async function() {
+    await Glean.testUninitialize();
+
+    const launchSpy = sandbox.spy(Context.dispatcher, "launch");
+    Glean.setUploadEnabled(false);
+    assert.strictEqual(launchSpy.callCount, 0);
+  });
+
   it("initialization throws if applicationId is an empty string", async function() {
     await Glean.testUninitialize();
     try {