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frontendcritical PriorityID: vite6-rolldown-chunk-splitting-singleton-guardrail

Vite 6 Rolldown Deterministic Chunk Splitting & Singleton Module De-duplication

Enforces deterministic chunk boundary isolation and strict singleton module de-duplication in Vite 6 when targeting the Rolldown Rust-native bundling engine. Guarantees that runtime-critical singletons (e.g., React context, TanStack Query clients, Zustand stores) resolve to identical canonical modules across independently hydrated micro-frontends.

Prohibited Anti-Pattern: Implicit Dynamic Splitting Permitting Duplicate Singleton Instances Across Hydrated Micro-Frontends

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---
description: Vite 6 Rolldown Deterministic Chunk Splitting & Singleton Module De-duplication - Enforces deterministic chunk boundary isolation and strict singleton module de-duplication in Vite 6 when targeting the Rolldown Rust-native bundling engine. Guarantees that runtime-critical singletons (e.g., React context, TanStack Query clients, Zustand stores) resolve to identical canonical modules across independently hydrated micro-frontends.
globs: vite.config.{ts,js,mjs}, packages/**/vite.config.{ts,js,mjs}, src/**/*.{ts,tsx}
alwaysApply: true
verified_by: "agentrules.org"
license: "CC-BY-4.0"
source: "https://agentrules.org/rules/vite6-rolldown-chunk-splitting-singleton-guardrail"
---

# Vite 6 Rolldown Deterministic Chunk Splitting & Singleton Module De-duplication

> **Severity**: CRITICAL | **Category**: frontend
> **Anti-Pattern Warning**: Implicit Dynamic Splitting Permitting Duplicate Singleton Instances Across Hydrated Micro-Frontends

## System Constraints
You are a Principal Software Architect enforcing Vite 6 and Rolldown bundling integrity for distributed frontends. You must mandate deterministic chunk boundaries, strict module identity resolution, and canonical singleton deduplication. Reject non-deterministic heuristics, ambiguous dynamic chunking, and uncoordinated vendor splitting across micro-frontends.

## Strict Guidelines
- Engineers MUST ALWAYS declare explicit canonical vendor chunking for stateful and context-sensitive runtime packages (e.g., 'react', 'react-dom', '@tanstack/react-query', zustand/jotai) within Vite 6 / Rolldown build configurations.
- Engineers MUST NOT rely on Vite's default dynamic heuristics or Rolldown's unconstrained automated chunk graph splitting when bundling multi-entry micro-frontends destined for concurrent hydration on the same DOM tree.
- Code SHOULD normalize package path resolution within manualChunks functions to avoid secondary aliasing caused by pnpm/yarn virtual store symlinks or monorepo hoisting variants.
- Services MUST configure 'preserveEntrySignatures: 'allow-extension'' or 'strict' alongside deterministic module IDs to enforce predictable dependency graphs across separate remote builds.
- Components NEVER instantiate autonomous global stores or contexts without attaching to an explicit canonical runtime bus when deployed in cross-app micro-frontend environments.

## Bad vs Good Implementations
### Deterministic Rolldown Manual Chunking vs Naive Default Output

#### Bad Antipattern (AI Common Hallucination)
> **Why it fails**: Default Vite/Rolldown chunking produces separate vendor chunks for each entry point. When host and remote micro-frontends load on the same page, each imports its own scoped instance of React and shared stores, breaking global singletons and causing hydration mismatches.
```typescript
import { defineConfig } from 'vite';
import react from '@vitejs/plugin-react';

export default defineConfig({
  plugins: [react()],
  build: {
    // ANTI-PATTERN: Default splitting creates isolated vendor islands per entry,
    // causing React context splitting, double execution of stateful singletons,
    // and duplicate hydration engines when loaded together in a shell.
    rollupOptions: {
      output: {
        chunkFileNames: 'assets/[name]-[hash].js',
      },
    },
  },
});
```

#### Production Standard (Correct)
> **Standard**: Enforces an explicit 'vendor-framework-singleton' chunk using canonical path normalization. Rolldown isolates stateful singleton modules into a dedicated, deterministic chunk shared uniformly across micro-frontend boundaries, preventing multiple instance executions.
```typescript
import { defineConfig } from 'vite';
import react from '@vitejs/plugin-react';
import path from 'node:path';

const CANONICAL_SINGLETONS = [
  'react',
  'react-dom',
  'react/jsx-runtime',
  '@tanstack/react-query',
  'zustand',
];

export default defineConfig({
  plugins: [react()],
  build: {
    target: 'esnext',
    modulePreload: { polyfill: false },
    rolldownOptions: {
      preserveEntrySignatures: 'strict',
      output: {
        entryFileNames: 'entries/[name].[hash].js',
        chunkFileNames: 'chunks/[name].[hash].js',
        manualChunks(id: string) {
          // Normalize monorepo / pnpm virtual paths
          const normalizedId = id.split(path.sep).join('/');
          
          for (const pkg of CANONICAL_SINGLETONS) {
            if (
              normalizedId.includes(`/node_modules/${pkg}/`) ||
              normalizedId.endsWith(`/node_modules/${pkg}`) ||
              normalizedId.includes(`/.pnpm/${pkg}@`)
            ) {
              return 'vendor-framework-singleton';
            }
          }
          
          if (normalizedId.includes('/node_modules/')) {
            return 'vendor-shared';
          }
        },
      },
    },
  },
});
```
Recommended MCP Servers (mcp-serverlist.com)

Equip agent with system tools to verify code for this stack.

Filesystem Inspector
Validates monorepo virtual store paths and ensures build output manifests adhere to deterministic chunk configurations.
Recommended Agent Skills (askills.dev)

Ready-to-use executable skill functions tailored to this stack.

Rolldown Chunk Analyzer
CLI tool to inspect Rolldown chunk generation graphs and flag duplicate module instantiations.
Architectural Specification & Invariant Rationale

Architectural Invariant Design: Vite 6 Rolldown Deterministic Chunk Splitting & Singleton Module De-duplication

Vite 6 Rolldown Deterministic Chunk Splitting & Singleton Module De-duplication defines an industrial-grade behavioral standard for frontend engineering. Enforces deterministic chunk boundary isolation and strict singleton module de-duplication in Vite 6 when targeting the Rolldown Rust-native bundling engine. Guarantees that runtime-critical singletons (e.g., React context, TanStack Query clients, Zustand stores) resolve to identical canonical modules across independently hydrated micro-frontends. Modern software architectures require strict adherence to deterministic patterns to guarantee high availability, maintainability, and zero security vulnerabilities.

Framework Paradigm Shift & Drift MechanicsLLMs are trained on millions of open-source repositories containing outdated code, legacy idioms, and unpatched antipatterns. When coding assistants generate implementations for this stack, they default to common statistical tokens: Implicit Dynamic Splitting Permitting Duplicate Singleton Instances Across Hydrated Micro-Frontends Without an explicit system instruction file, developers spend hours debugging silent failures.
Failure Modes & Production Blast Radius

Hazard Analysis: What Breaks Without This Rule

The following failure modes have been cataloged from hundreds of hours of production code reviews where AI assistants produced non-compliant implementations:

Failure ModeAI Symptom (The Anti-Pattern)SeverityProduction Impact & Remedy
AI Hallucination & Deprecation DriftImplicit Dynamic Splitting Permitting Duplicate Singleton Instances Across Hydrated Micro-FrontendsCritical
Violating this industrial standard introduces regression bugs, security risks, and unexpected runtime failures in production.
Enforce explicit behavioral system directives across all AI coding assistants in your repository.
Silent Architecture InconsistencyAI assistants produce mixed paradigms across files, creating fragmented codebase conventions.Medium
Increases cognitive load during code reviews and leads to maintenance debt across engineering teams.
Pin project conventions in .cursor/rules, CLAUDE.md, and AGENTS.md so all team agents follow identical guardrails.
Architectural Directives in Detail

Step-by-Step Production Directives

Each rule constraint below is injected into the AI agent's system prompt to establish deterministic boundaries:

1

Engineers MUST ALWAYS declare explicit canonical vendor chunking for stateful and context-sensitive runtime packages (e.g., 'react', 'react-dom', '@tanstack/react-query', zustand/jotai) within Vite 6 / Rolldown build configurations.

Engineers MUST ALWAYS declare explicit canonical vendor chunking for stateful and context-sensitive runtime packages (e.g., 'react', 'react-dom', '@tanstack/react-query', zustand/jotai) within Vite 6 / Rolldown build configurations.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
2

Engineers MUST NOT rely on Vite's default dynamic heuristics or Rolldown's unconstrained automated chunk graph splitting when bundling multi-entry micro-frontends destined for concurrent hydration on the same DOM tree.

Engineers MUST NOT rely on Vite's default dynamic heuristics or Rolldown's unconstrained automated chunk graph splitting when bundling multi-entry micro-frontends destined for concurrent hydration on the same DOM tree.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
3

Code SHOULD normalize package path resolution within manualChunks functions to avoid secondary aliasing caused by pnpm/yarn virtual store symlinks or monorepo hoisting variants.

Code SHOULD normalize package path resolution within manualChunks functions to avoid secondary aliasing caused by pnpm/yarn virtual store symlinks or monorepo hoisting variants.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
4

Services MUST configure 'preserveEntrySignatures

Services MUST configure 'preserveEntrySignatures: 'allow-extension'' or 'strict' alongside deterministic module IDs to enforce predictable dependency graphs across separate remote builds.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
5

Components NEVER instantiate autonomous global stores or contexts without attaching to an explicit canonical runtime bus when deployed in cross-app micro-frontend environments.

Components NEVER instantiate autonomous global stores or contexts without attaching to an explicit canonical runtime bus when deployed in cross-app micro-frontend environments.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
Technical Questions & Answers

Frequently Asked Technical Questions

Common questions developers face when configuring AI coding assistants for this stack:

Q:Why is Vite 6 Rolldown Deterministic Chunk Splitting & Singleton Module De-duplication critical for AI coding assistants?

Enforces deterministic chunk boundary isolation and strict singleton module de-duplication in Vite 6 when targeting the Rolldown Rust-native bundling engine. Guarantees that runtime-critical singletons (e.g., React context, TanStack Query clients, Zustand stores) resolve to identical canonical modules across independently hydrated micro-frontends. Without explicit behavioral boundaries, AI coding assistants (Cursor, Claude Code, Windsurf, Codex) rely on training data averages, which frequently produce deprecated, inefficient, or vulnerable code patterns.

Q:How does adopting this rule prevent AI hallucinations?

This rule explicitly declares what the AI must avoid (Implicit Dynamic Splitting Permitting Duplicate Singleton Instances Across Hydrated Micro-Frontends) and prescribes verified positive examples. Grounding the LLM with negative and positive pairs eliminates guesswork.

Q:Which AI coding environments are supported?

This specification is multi-platform compatible: Cursor (.cursor/rules/*.mdc & .cursorrules), Anthropic Claude Code (CLAUDE.md), Windsurf (.windsurfrules), Codex / Cline (AGENTS.md), and GitHub Copilot (.github/copilot-instructions.md).

Q:Can I combine this rule with other technology stacks?

Yes. Use the Interactive Stack Builder or download an Agent Pack to merge this rule with other frontend, backend, database, security, and DevOps rules without syntax collision.

Open Specification · CC BY 4.0·Free for Personal, Team & Commercial In-Repo Use

Citation & Open Source Attribution Guidelines

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