feat(init): opt yarn projects out of plug'n'play

Author: danielroe

packages/nuxt-cli/src/commands/init.ts

@@ -5,6 +5,7 @@ import type { InstallResult } from '../utils/install'
 importtype{TemplateData}from'../utils/starter-templates'
 
 import{existsSync}from'node:fs'
+import{writeFile}from'node:fs/promises'
 importprocessfrom'node:process'
 import{Writable}from'node:stream'
 
@@ -85,6 +86,27 @@ async function reportMissingNonInteractiveArgs<T extends ArgsDef>(
 .join(', ')}`)
 }
 
+constYARN_NODE_LINKER=`# Nuxt cannot resolve its modules under Yarn's default Plug'n'Play linker.
+# See https://github.com/nuxt/nuxt/issues/26750
+nodeLinker: node-modules
+`
+
+/**
+ * Opt a scaffolded project out of Yarn's Plug'n'Play linker, under which
+ * `nuxt prepare` cannot resolve `@nuxt/kit` and the project will not build.
+ *
+ * Templates that ship any Yarn configuration of their own are left alone, so a
+ * template can still choose Plug'n'Play. Yarn 1 ignores `.yarnrc.yml`, so
+ * writing it there is harmless.
+ */
+exportasyncfunctionuseYarnNodeModulesLinker(dir: string): Promise<boolean>{
+if(existsSync(join(dir,'.yarnrc.yml'))||existsSync(join(dir,'.yarnrc'))){
+returnfalse
+}
+awaitwriteFile(join(dir,'.yarnrc.yml'),YARN_NODE_LINKER,'utf8')
+returntrue
+}
+
 /**
  * Commands to print in the closing 'Next steps' box, in the order to run them.
  *
@@ -505,6 +527,10 @@ export default defineCommand({
 selectedPackageManager=result
 }
 
+if(selectedPackageManager==='yarn'&&awaituseYarnNodeModulesLinker(template.dir)){
+logger.info(`Created ${colors.cyan('.yarnrc.yml')} with ${colors.cyan('nodeLinker: node-modules')}, as Nuxt cannot resolve its modules under Yarn's Plug'n'Play linker.`)
+}
+
 // Determine if we should init git
 letgitInit: boolean|undefined=ctx.args.gitInit==='false'asunknown ? false : ctx.args.gitInit
 if(gitInit===undefined){

packages/nuxt-cli/test/unit/commands/init.spec.ts

@@ -1,9 +1,39 @@
-import{mkdtemp,rm,writeFile}from'node:fs/promises'
+import{existsSync}from'node:fs'
+import{mkdtemp,readFile,rm,writeFile}from'node:fs/promises'
 import{tmpdir}from'node:os'
 import{join}from'node:path'
 import{afterEach,beforeEach,describe,expect,it}from'vitest'
 
-import{detectTemplatePackageManager,getNextSteps}from'../../../src/commands/init'
+import{detectTemplatePackageManager,getNextSteps,useYarnNodeModulesLinker}from'../../../src/commands/init'
+
+describe('useYarnNodeModulesLinker',()=>{
+letdir: string
+
+beforeEach(async()=>{
+dir=awaitmkdtemp(join(tmpdir(),'nuxt-init-yarn-'))
+})
+
+afterEach(async()=>{
+awaitrm(dir,{recursive: true,force: true})
+})
+
+it('should opt a fresh project out of plug\'n\'play',async()=>{
+expect(awaituseYarnNodeModulesLinker(dir)).toBe(true)
+expect(awaitreadFile(join(dir,'.yarnrc.yml'),'utf8')).toContain('nodeLinker: node-modules')
+})
+
+it('should not overwrite yarn configuration from a template',async()=>{
+awaitwriteFile(join(dir,'.yarnrc.yml'),'nodeLinker: pnp\n')
+expect(awaituseYarnNodeModulesLinker(dir)).toBe(false)
+expect(awaitreadFile(join(dir,'.yarnrc.yml'),'utf8')).toBe('nodeLinker: pnp\n')
+})
+
+it('should not add yarn 2+ configuration alongside a yarn 1 config',async()=>{
+awaitwriteFile(join(dir,'.yarnrc'),'registry "https://example.com"\n')
+expect(awaituseYarnNodeModulesLinker(dir)).toBe(false)
+expect(existsSync(join(dir,'.yarnrc.yml'))).toBe(false)
+})
+})
 
 describe('getNextSteps',()=>{
 constbase={shell: false,recoveryCommands: []asstring[],packageManager: 'npm'asconst}