Fix rspack race condition in injection

packages/plugins/injection/src/xpack.ts

@@ -3,7 +3,7 @@
 // Copyright 2019-Present Datadog, Inc.
 
 import { INJECTED_FILE } from '@dd/core/constants';
-import { getUniqueId } from '@dd/core/helpers';
+import { getUniqueId, outputFile, rm } from '@dd/core/helpers';
 import type { GlobalContext, Logger, PluginOptions, ToInjectItem } from '@dd/core/types';
 import { InjectPosition } from '@dd/core/types';
 import { createRequire } from 'module';
@@ -102,10 +102,22 @@ export const getXpackPlugin =
         // We need to prepare the injections before the build starts.
         // Otherwise they'll be empty once resolved.
         compiler.hooks.beforeRun.tapPromise(PLUGIN_NAME, async () => {
+            // RSpack MAY try to resolve the entry points before the loader is ready.
+            // There must be some race condition around this, because it's not always the case.
+            if (context.bundler.name === 'rspack') {
+                await outputFile(filePath, '');
+            }
             // Prepare the injections.
             await addInjections(log, toInject, contentsToInject, context.cwd);
         });
 
+        if (context.bundler.name === 'rspack') {
+            compiler.hooks.done.tapPromise(PLUGIN_NAME, async () => {
+                // Delete the fake file we created.
+                await rm(filePath);
+            });
+        }
+
         // Handle the InjectPosition.START and InjectPosition.END.
         // This is a re-implementation of the BannerPlugin,
         // that is compatible with all versions of webpack and rspack,