feat(nuxt): Added support for nuxt layers (#16372)

Added ability to detect and import config files from the **active** nuxt
layer with strategy of the **most latest** layer taking precedence.
Included fallback behavior for good measure.

Rest of the config should be merged as it already is by c12 and defu. 

Don't think this PR covers the git:repo based layers but those are
generally not full supported as well in Nuxt 3 ecosystem.

Added basic tests

Resolves
[#14345](#14345)

---------

Co-authored-by: Ivan Pesic <[email protected]>

Author: Xenossolitarius

packages/nuxt/src/module.ts

@@ -35,7 +35,7 @@ export default defineNuxtModule<ModuleOptions>({
     const moduleDirResolver = createResolver(import.meta.url);
     const buildDirResolver = createResolver(nuxt.options.buildDir);
 
-    const clientConfigFile = findDefaultSdkInitFile('client');
+    const clientConfigFile = findDefaultSdkInitFile('client', nuxt);
 
     if (clientConfigFile) {
       // Inject the client-side Sentry config file with a side effect import
@@ -59,7 +59,7 @@ export default defineNuxtModule<ModuleOptions>({
       addPlugin({ src: moduleDirResolver.resolve('./runtime/plugins/sentry.client'), mode: 'client' });
     }
 
-    const serverConfigFile = findDefaultSdkInitFile('server');
+    const serverConfigFile = findDefaultSdkInitFile('server', nuxt);
 
     if (serverConfigFile) {
       addServerPlugin(moduleDirResolver.resolve('./runtime/plugins/sentry.server'));

packages/nuxt/src/vite/utils.ts

@@ -1,29 +1,49 @@
 import { consoleSandbox } from '@sentry/core';
 import * as fs from 'fs';
+import type { Nuxt } from 'nuxt/schema';
 import * as path from 'path';
 
 /**
  *  Find the default SDK init file for the given type (client or server).
  *  The sentry.server.config file is prioritized over the instrument.server file.
  */
-export function findDefaultSdkInitFile(type: 'server' | 'client'): string | undefined {
+export function findDefaultSdkInitFile(type: 'server' | 'client', nuxt?: Nuxt): string | undefined {
   const possibleFileExtensions = ['ts', 'js', 'mjs', 'cjs', 'mts', 'cts'];
-  const cwd = process.cwd();
+  const relativePaths: string[] = [];
 
-  const filePaths: string[] = [];
   if (type === 'server') {
     for (const ext of possibleFileExtensions) {
-      // order is important here - we want to prioritize the server.config file
-      filePaths.push(path.join(cwd, `sentry.${type}.config.${ext}`));
-      filePaths.push(path.join(cwd, 'public', `instrument.${type}.${ext}`));
+      relativePaths.push(`sentry.${type}.config.${ext}`);
+      relativePaths.push(path.join('public', `instrument.${type}.${ext}`));
     }
   } else {
     for (const ext of possibleFileExtensions) {
-      filePaths.push(path.join(cwd, `sentry.${type}.config.${ext}`));
+      relativePaths.push(`sentry.${type}.config.${ext}`);
+    }
+  }
+
+  // Get layers from highest priority to lowest
+  const layers = [...(nuxt?.options._layers ?? [])].reverse();
+
+  for (const layer of layers) {
+    for (const relativePath of relativePaths) {
+      const fullPath = path.resolve(layer.cwd, relativePath);
+      if (fs.existsSync(fullPath)) {
+        return fullPath;
+      }
+    }
+  }
+
+  // As a fallback, also check CWD (left for pure compatibility)
+  const cwd = process.cwd();
+  for (const relativePath of relativePaths) {
+    const fullPath = path.resolve(cwd, relativePath);
+    if (fs.existsSync(fullPath)) {
+      return fullPath;
     }
   }
 
-  return filePaths.find(filename => fs.existsSync(filename));
+  return undefined;
 }
 
 /**

packages/nuxt/test/vite/utils.test.ts

@@ -1,4 +1,5 @@
 import * as fs from 'fs';
+import type { Nuxt } from 'nuxt/schema';
 import { afterEach, describe, expect, it, vi } from 'vitest';
 import {
   constructFunctionReExport,
@@ -69,6 +70,75 @@ describe('findDefaultSdkInitFile', () => {
     const result = findDefaultSdkInitFile('server');
     expect(result).toMatch('packages/nuxt/sentry.server.config.js');
   });
+
+  it('should return the latest layer config file path if client config exists', () => {
+    vi.spyOn(fs, 'existsSync').mockImplementation(filePath => {
+      return !(filePath instanceof URL) && filePath.includes('sentry.client.config.ts');
+    });
+
+    const nuxtMock = {
+      options: {
+        _layers: [
+          {
+            cwd: 'packages/nuxt/module',
+          },
+          {
+            cwd: 'packages/nuxt',
+          },
+        ],
+      },
+    } as Nuxt;
+
+    const result = findDefaultSdkInitFile('client', nuxtMock);
+    expect(result).toMatch('packages/nuxt/sentry.client.config.ts');
+  });
+
+  it('should return the latest layer config file path if server config exists', () => {
+    vi.spyOn(fs, 'existsSync').mockImplementation(filePath => {
+      return (
+        !(filePath instanceof URL) &&
+        (filePath.includes('sentry.server.config.ts') || filePath.includes('instrument.server.ts'))
+      );
+    });
+
+    const nuxtMock = {
+      options: {
+        _layers: [
+          {
+            cwd: 'packages/nuxt/module',
+          },
+          {
+            cwd: 'packages/nuxt',
+          },
+        ],
+      },
+    } as Nuxt;
+
+    const result = findDefaultSdkInitFile('server', nuxtMock);
+    expect(result).toMatch('packages/nuxt/sentry.server.config.ts');
+  });
+
+  it('should return the latest layer config file path if client config exists in former layer', () => {
+    vi.spyOn(fs, 'existsSync').mockImplementation(filePath => {
+      return !(filePath instanceof URL) && filePath.includes('nuxt/sentry.client.config.ts');
+    });
+
+    const nuxtMock = {
+      options: {
+        _layers: [
+          {
+            cwd: 'packages/nuxt/module',
+          },
+          {
+            cwd: 'packages/nuxt',
+          },
+        ],
+      },
+    } as Nuxt;
+
+    const result = findDefaultSdkInitFile('client', nuxtMock);
+    expect(result).toMatch('packages/nuxt/sentry.client.config.ts');
+  });
 });
 
 describe('getFilenameFromPath', () => {