feat: bump Rspack dependencies to v2 (^2.0.0-0)

Update generator and bin/switch-bundler Rspack dependencies from v1 to v2:
- @rspack/core@^2.0.0-0 (prerelease suffix includes RC builds)
- @rspack/cli@^2.0.0-0
- @rspack/plugin-react-refresh@^2.0.0 (already stable at 2.0.0)
- rspack-manifest-plugin@^5.0.0 (unchanged, already compatible)

The -0 prerelease suffix ensures that RC builds (currently 2.0.0-rc.1)
are resolved by npm until stable 2.0.0 ships.

Closes #3082

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ihabadham

CHANGELOG.md

@@ -24,6 +24,10 @@ After a release, run `/update-changelog` in Claude Code to analyze commits, writ
 
 ### [Unreleased]
 
+#### Changed
+
+- **Bump Rspack dependencies to v2**: Updated generator and `bin/switch-bundler` Rspack dependencies from v1 to v2 (`@rspack/core@^2.0.0-0`, `@rspack/cli@^2.0.0-0`, `@rspack/plugin-react-refresh@^2.0.0`). The `-0` prerelease suffix ensures RC builds are included until stable 2.0.0 lands. `rspack-manifest-plugin` remains at `^5.0.0` (already compatible with Rspack v2). Closes [Issue 3082](https://github.com/shakacode/react_on_rails/issues/3082). [PR 3084](https://github.com/shakacode/react_on_rails/pull/3084) by [justin808](https://github.com/justin808).
+
 ### [16.6.0] - 2026-04-09
 
 #### Removed

react_on_rails/lib/generators/react_on_rails/js_dependency_manager.rb

@@ -91,16 +91,19 @@ module JsDependencyManager
       ].freeze
 
       # Rspack core dependencies (only installed when --rspack flag is used)
+      # @rspack/core uses ^2.0.0-0 (with -0 prerelease suffix) to include RC/beta prereleases
+      # of 2.0.0 until the stable 2.0.0 release lands.
       RSPACK_DEPENDENCIES = %w[
-        @rspack/core@^1.0.0
+        @rspack/core@^2.0.0-0
         rspack-manifest-plugin@^5.0.0
       ].freeze
 
       # Rspack development dependencies for hot reloading
       # react-refresh is pre-1.0, so left bare (see pinning note above).
+      # @rspack/cli uses ^2.0.0-0 to match @rspack/core's prerelease range.
       RSPACK_DEV_DEPENDENCIES = %w[
-        @rspack/cli@^1.0.0
-        @rspack/plugin-react-refresh@^1.0.0
+        @rspack/cli@^2.0.0-0
+        @rspack/plugin-react-refresh@^2.0.0
         react-refresh
       ].freeze
 

react_on_rails/lib/generators/react_on_rails/templates/base/base/bin/switch-bundler

@@ -15,8 +15,8 @@ class BundlerSwitcher
   }.freeze
 
   RSPACK_DEPS = {
-    dependencies: %w[@rspack/core@^1.0.0 rspack-manifest-plugin@^5.0.0],
-    dev_dependencies: %w[@rspack/cli@^1.0.0 @rspack/plugin-react-refresh@^1.0.0]
+    dependencies: %w[@rspack/core@^2.0.0-0 rspack-manifest-plugin@^5.0.0],
+    dev_dependencies: %w[@rspack/cli@^2.0.0-0 @rspack/plugin-react-refresh@^2.0.0]
   }.freeze
 
   def initialize(target_bundler)

react_on_rails/spec/react_on_rails/generators/install_generator_spec.rb

@@ -667,7 +667,7 @@ class ActiveSupport::TestCase
     it "switch-bundler has version-pinned deps and strips versions before deletion" do
       assert_file "bin/switch-bundler" do |content|
         # Version pins are present in the constants
-        expect(content).to include("@rspack/core@^1.0.0")
+        expect(content).to include("@rspack/core@^2.0.0-0")
         expect(content).to include("webpack@^5.0.0")
         # Version-stripping regex is used for package.json key deletion
         expect(content).to include('dep[%r{\A(@[^/]+/[^@]+|[^@]+)}]')

react_on_rails/spec/react_on_rails/generators/js_dependency_manager_spec.rb

@@ -140,14 +140,14 @@ def errors
 
     it "defines RSPACK_DEPENDENCIES" do
       expect(ReactOnRails::Generators::JsDependencyManager::RSPACK_DEPENDENCIES).to eq(%w[
-                                                                                         @rspack/core@^1.0.0
+                                                                                         @rspack/core@^2.0.0-0
                                                                                          rspack-manifest-plugin@^5.0.0
                                                                                        ])
     end
 
     it "defines RSPACK_DEV_DEPENDENCIES" do
       expect(ReactOnRails::Generators::JsDependencyManager::RSPACK_DEV_DEPENDENCIES).to(
-        eq(%w[@rspack/cli@^1.0.0 @rspack/plugin-react-refresh@^1.0.0 react-refresh])
+        eq(%w[@rspack/cli@^2.0.0-0 @rspack/plugin-react-refresh@^2.0.0 react-refresh])
       )
     end