build(deps): bump shakapacker from 8.4.0 to 9.0.0

[dependabot]

Bumps shakapacker from 8.4.0 to 9.0.0.

Changelog

Sourced from shakapacker's changelog.

[v9.0.0] - October 5, 2025

See the v9 Upgrade Guide for detailed migration instructions.

⚠️ Breaking Changes

1. SWC is now the default JavaScript transpiler instead of Babel (PR 603 by justin808)

   • Babel dependencies are no longer included as peer dependencies
   • Improves compilation speed by 20x
   • Migration for existing projects:
     • Option 1 (Recommended): Switch to SWC - Run rake shakapacker:migrate_to_swc or manually:

       # config/shakapacker.yml
       javascript_transpiler: "swc"

       Then install: npm install @swc/core swc-loader
     • Option 2: Keep using Babel:

       # config/shakapacker.yml
       javascript_transpiler: "babel"

2. CSS Modules now use named exports by default (PR 599)

   • JavaScript: Use named imports: import { className } from './styles.module.css'
   • TypeScript: Use namespace imports: import * as styles from './styles.module.css'
   • To keep the old behavior with default imports, see CSS Modules Export Mode documentation for configuration instructions

3. Configuration option renamed from webpack_loader to javascript_transpiler

   • Better reflects its purpose of configuring JavaScript transpilation
   • Old webpack_loader option deprecated but still supported with warning

Added

• Rspack support as an alternative assets bundler to webpack (PR 589, PR 590)
  • Configure assets_bundler: 'rspack' in shakapacker.yml
  • Faster Rust-based bundling with webpack-compatible APIs
  • Built-in SWC loader and CSS extraction
  • Automatic bundler detection in bin/shakapacker
• TypeScript type definitions for improved IDE support and autocomplete (PR 602)
  • Types available via import type { WebpackConfig, RspackConfig, EnvironmentConfig } from "shakapacker/types"
  • Installer automatically creates TypeScript config files when tsconfig.json is detected (PR 633)
  • See TypeScript Documentation for migration and usage instructions
• Optional peer dependencies - All peer dependencies now marked as optional, preventing installation warnings while maintaining version compatibility tracking (PR 603)
• Private output path for server-side rendering bundles (PR 592)
  • Configure private_output_path for private server bundles separate from public assets
• rake shakapacker:doctor diagnostic command to check for configuration issues and missing dependencies (PR 609)
• rake shakapacker:migrate_to_swc migration helper to assist with switching from Babel to SWC (PR 613, PR 635)

... (truncated)

Commits

• 1d6dc5a Release 9.0.0
• 8f17234 Add TypeScript config support to installer (#633)
• b81a885 Update spec/dummy Gemfile.lock after release
• 7347394 Release 9.0.0-beta.11
• 57d7aa0 Fix SWC migration to use config/swc.config.js instead of .swcrc (#634) (#635)
• 4fe4c30 Update spec/dummy Gemfile.lock after release
• 35e6171 Release 9.0.0-beta.10
• 9425c01 Fix NODE_ENV defaulting to production breaking dev server (#631) (#632)
• 55b05bc Update spec/dummy Gemfile.lock after release
• 5152cd5 Release 9.0.0-beta.9
• Additional commits viewable in compare view

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[dependabot]

Superseded by #2204.