[Bug]: paired CSS and loader edits can commit the previous server loader #147

// Executes actual controller, coordinator and identity helpers. All attempt tokens
// are created by controller hooks; this harness never supplies graph identities.
const fs=require('node:fs'),vm=require('node:vm'),assert=require('node:assert/strict'),path=require('node:path');
const {stripTypeScriptTypes}=require('node:module');
const dirs={'0.8.0':path.resolve(process.argv[2] || './package')};
const strip=file=>stripTypeScriptTypes(fs.readFileSync(file,'utf8')).replace(/^import[\s\S]*?;\n/gm,'').replace(/\bexport\s+(?=(?:const|function|class)\b)/g,'');
async function run(version,patched,ordering){
 const dir=dirs[version],callbacks={},warnings=[],errors=[],attempts=[];let binding,evaluations=0;
 const api={logger:{error:e=>errors.push(e),warn:w=>warnings.push(w)},modifyRsbuildConfig(){},onBeforeStartDevServer:x=>callbacks.start=x.handler,onCloseDevServer(){},onBeforeDevCompile:x=>callbacks.before=x.handler,onAfterCreateCompiler:x=>callbacks.created=x,onAfterDevCompile:x=>callbacks.after=x};
 const makeBuild=value=>({routes:{root:{module:{loader:()=>value}}}});
 const server={currentBuild:makeBuild('old'),sockWrite(){},environments:{web:{hot:{}}}};
 const sessions={getActiveBinding:()=>binding,assertCanStart(){},createBinding:(server,runtime)=>binding={id:Symbol(),server,runtime},bindCloseObservation(){}};
 const context={console,structuredClone,Set,Map,WeakMap,WeakSet,Symbol,Object,Array,Error,Promise,Reflect,JSON,Boolean,isAbsolute:path.isAbsolute,relative:path.relative,Date,
 setTimeout(){return 1},clearTimeout(){},PLUGIN_NAME:'react-router',DEV_MANIFEST_UPDATE_EVENT:'react-router:manifest-update',
 HMR_PATCHABLE_ROUTE_FLAGS:['hasLoader','hasAction','hasClientLoader','hasClientAction','hasClientMiddleware','hasErrorBoundary'],
 FiberId:{none:{}},EffectDeferred:{unsafeMake:()=>({}),unsafeDone(){}},Effect:{succeed:x=>x,fail:x=>x},normalizeEffectError:x=>x,
 evaluateServerBuilds:async()=>{evaluations++;return{app:server.currentBuild}},createDevRuntimeSessionManager:()=>sessions,createDevHdrChannel:()=>({publish(){},close(){}}),
 };
 let artifacts=strip(dir+'/src/dev-runtime-artifacts.ts');artifacts=artifacts.slice(0,artifacts.indexOf('const startServerBuildEvaluationEffect'))+artifacts.slice(artifacts.indexOf('const assertBuildMatchesManifest'));
 let generation=strip(dir+'/src/dev-generation.ts');if(patched){const needle='(!nodeChanged || identity.nodeWeb !== webIdentity)';assert.equal(generation.split(needle).length,2);generation=generation.replace(needle,'(!nodeChanged || (!identity.attempt && identity.nodeWeb !== webIdentity))');}
 vm.runInNewContext([artifacts,generation,strip(dir+'/src/dev-runtime-compilation.ts'),version==='0.8.0'?strip(dir+'/src/dev-hdr-intent.ts'):'',strip(dir+'/src/dev-runtime-controller.ts'),'globalThis.create=createReactRouterDevRuntimeController;'].join('\n'),context);
 const controller=context.create({api,isBuild:false,buildPlan:{entryNames:['app'],defaultEntryName:'app'}});
 const compiler=name=>{const hooks={};for(const key of ['invalid','done','thisCompilation','afterDone','failed']){const fns=[];hooks[key]={tap:(_name,fn)=>fns.push(fn),call:(...args)=>fns.forEach(fn=>fn(...args))};}return{name,hooks,modifiedFiles:new Set(),removedFiles:new Set()};};
 await callbacks.start({server});const web=compiler('web'),node=compiler('node');callbacks.created({compiler:{compilers:[web,node]}});
 const realFinish=binding.runtime.finishAttempt.bind(binding.runtime);
 binding.runtime.finishAttempt=async(stats,changes,identity)=>{attempts.push({paired:!!identity.attempt,nodeStartedAfterThisWebFinished:identity.nodeWeb===identity.web});return realFinish(stats,changes,identity)};
 const compile=compiler=>{const compilation={name:compiler.name,compiler,fileDependencies:new Set(['/root.tsx']),buildDependencies:new Set(),contextDependencies:new Set(),missingDependencies:new Set()};compiler.hooks.thisCompilation.call(compilation);return{hasErrors:()=>false,compilation}};
 const complete=stats=>{const compiler=stats.compilation.compiler;compiler.hooks.done.call(stats);compiler.hooks.afterDone.call(stats)};
 const manifest=css=>({app:{version:css,entry:{module:'/entry.js',imports:[],css:[]},routes:{root:{id:'root',module:'/root.js',imports:[],css:[css],hasLoader:true}}}});
 callbacks.before();const baseWeb=compile(web);controller.captureWeb(baseWeb.compilation,manifest('/old.css'));complete(baseWeb);const baseNode=compile(node);complete(baseNode);
 await callbacks.after({stats:{web:baseWeb,node:baseNode}});await new Promise(setImmediate);
 assert.equal((await controller.createBuildLoader()()).routes.root.module.loader(),'old');
 server.currentBuild=makeBuild('new');web.modifiedFiles=new Set(['/root.tsx']);node.modifiedFiles=new Set(['/root.tsx']);
 if(ordering==='paired-with-invalid-hooks'){web.hooks.invalid.call();node.hooks.invalid.call();}
 callbacks.before();const nextNode=compile(node);
 if(ordering==='unpaired-overlap')web.hooks.invalid.call();
 const nextWeb=compile(web);controller.captureWeb(nextWeb.compilation,manifest('/new.css'));complete(nextWeb);complete(nextNode);
 await callbacks.after({stats:{web:nextWeb,node:nextNode}});await new Promise(setImmediate);
 const committed=await controller.createBuildLoader()();const expected=patched&&ordering!=='unpaired-overlap'?'new':'old';
 assert.equal(attempts.length,2);assert.equal(attempts[1].paired,ordering!=='unpaired-overlap');assert.equal(attempts[1].nodeStartedAfterThisWebFinished,false);
 assert.equal(committed.routes.root.module.loader(),expected);assert.equal(committed.assets.routes.root.css[0],'/new.css');assert.equal(errors.length,0);assert.equal(warnings.length,0);assert.equal(evaluations,expected==='new'?2:1);
 return{version,patched,ordering,controllerGeneratedPairedIdentity:attempts[1].paired,nodeWebReferencesPreviousCompilation:true,loaderValue:committed.routes.root.module.loader(),css:committed.assets.routes.root.css[0],evaluations};
}
(async()=>{const results=[];for(const version of Object.keys(dirs))for(const patched of [false,true])for(const ordering of ['paired-aggregate-hook','paired-with-invalid-hooks','unpaired-overlap'])results.push(await run(version,patched,ordering));console.log(JSON.stringify({method:'Actual controller+coordinator+identity helpers; fake compiler hooks, mocked bundle evaluation, no manual attempt identities, no bundler/server/browser',results},null,2));})().catch(e=>{console.error(e);process.exitCode=1});