warn about missing instrumentation file

and only warn about missing onRequestError when an instrumentation file
exists

Author: a-hariti

packages/nextjs/src/config/webpack.ts

@@ -448,18 +448,42 @@ function warnAboutMissingonRequestErrorHandler(projectDir: string): void {
     ['instrumentation.ts'],
     ['instrumentation.js'],
   ];
-  function hasOnRequestErrorHandler(pathSegments: string[]): boolean {
-    const filePath = path.resolve(projectDir, ...pathSegments);
+  const instrumentationFile = instrumentationPaths
+    .map(pathSegments => path.resolve(projectDir, ...pathSegments))
+    .find(function exists(filePath: string): string | null {
+      try {
+        fs.accessSync(filePath, fs.constants.F_OK);
+        return filePath;
+      } catch (error) {
+        return null;
+      }
+    });
+
+  function hasOnRequestErrorHandler(absolutePath: string): boolean {
     try {
-      const content = fs.readFileSync(filePath, 'utf8');
+      const content = fs.readFileSync(absolutePath, 'utf8');
       return content.includes('export const onRequestError');
     } catch (error) {
       return false;
     }
   }
-  if (!instrumentationPaths.some(hasOnRequestErrorHandler)) {
+
+  if (!instrumentationFile) {
+    // eslint-disable-next-line no-console
+    return console.warn(
+      `${chalk.yellow(
+        '[@sentry/nextjs]',
+      )} Could not find instrumentation file: https://docs.sentry.io/platforms/javascript/guides/nextjs/manual-setup/#create-initialization-config-files`,
+    );
+  }
+
+  if (!hasOnRequestErrorHandler(instrumentationFile)) {
     // eslint-disable-next-line no-console
-    console.warn(`${chalk.yellow('[@sentry/nextjs]')} Could not find \`onRequestError\` hook in instrumentation file. This indicates outdated configuration of the Sentry SDK. Use \`Sentry.captureRequestError\` to instrument the \`onRequestError\` hook: https://docs.sentry.io/platforms/javascript/guides/nextjs/manual-setup/#errors-from-nested-react-server-components`);
+    console.warn(
+      `${chalk.yellow(
+        '[@sentry/nextjs]',
+      )} Could not find \`onRequestError\` hook in instrumentation file. This indicates outdated configuration of the Sentry SDK. Use \`Sentry.captureRequestError\` to instrument the \`onRequestError\` hook: https://docs.sentry.io/platforms/javascript/guides/nextjs/manual-setup/#errors-from-nested-react-server-components`,
+    );
   }
 }