Merge pull request #260 from skryukov/fix-errors-with-partials

Update errors params handling

Author: bknoles

.rubocop_todo.yml

@@ -1,6 +1,6 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config --exclude-limit 10000`
-# on 2025-07-25 08:41:37 UTC using RuboCop version 1.79.0.
+# on 2025-08-27 13:50:45 UTC using RuboCop version 1.80.1.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
@@ -81,14 +81,13 @@ Layout/SpaceInsideBlockBraces:
     - 'spec/inertia/error_sharing_spec.rb'
     - 'spec/inertia/request_spec.rb'
 
-# Offense count: 56
+# Offense count: 54
 # This cop supports safe autocorrection (--autocorrect).
 # Configuration parameters: EnforcedStyle, EnforcedStyleForEmptyBraces.
 # SupportedStyles: space, no_space, compact
 # SupportedStylesForEmptyBraces: space, no_space
 Layout/SpaceInsideHashLiteralBraces:
   Exclude:
-    - 'lib/inertia_rails/controller.rb'
     - 'spec/dummy/app/controllers/inertia_conditional_sharing_controller.rb'
     - 'spec/dummy/app/controllers/inertia_share_test_controller.rb'
     - 'spec/inertia/conditional_sharing_spec.rb'
@@ -198,7 +197,7 @@ Style/ColonMethodCall:
 
 # Offense count: 1
 # This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: AutoCorrect, EnforcedStyle, AllowComments.
+# Configuration parameters: EnforcedStyle, AllowComments.
 # SupportedStyles: empty, nil, both
 Style/EmptyElse:
   Exclude:
@@ -212,7 +211,7 @@ Style/EmptyLiteral:
 
 # Offense count: 2
 # This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: AutoCorrect, EnforcedStyle.
+# Configuration parameters: EnforcedStyle.
 # SupportedStyles: compact, expanded
 Style/EmptyMethod:
   Exclude:
@@ -404,7 +403,7 @@ Style/SoleNestedConditional:
   Exclude:
     - 'lib/inertia_rails/controller.rb'
 
-# Offense count: 81
+# Offense count: 85
 # This cop supports safe autocorrection (--autocorrect).
 # Configuration parameters: EnforcedStyle, ConsistentQuotesInMultiline.
 # SupportedStyles: single_quotes, double_quotes
@@ -466,7 +465,7 @@ Style/TrailingCommaInHashLiteral:
     - 'spec/inertia/response_spec.rb'
     - 'spec/inertia/rspec_helper_spec.rb'
 
-# Offense count: 32
+# Offense count: 36
 # This cop supports safe autocorrection (--autocorrect).
 # Configuration parameters: AllowHeredoc, AllowURI, AllowQualifiedName, URISchemes, IgnoreCopDirectives, AllowedPatterns, SplitStrings.
 # URISchemes: http, https

docs/guide/configuration.md

@@ -103,6 +103,19 @@ forcing a full page visit instead of an XHR visit on the next request.
 
 See [assets versioning](/guide/asset-versioning).
 
+### `always_include_errors_hash`
+
+**Default**: `nil`
+**ENV**: `INERTIA_ALWAYS_INCLUDE_ERRORS_HASH`
+
+@available_since rails=master
+
+Whether to include an empty `errors` hash in the props when no validation errors are present.
+
+When set to `true`, an empty `errors: {}` object will always be included in Inertia responses. When set to `false`, the `errors` key will be omitted when there are no errors. The default value `nil` currently behaves like `false` but shows a deprecation warning.
+
+The default value will be changed to `true` in the next major version.
+
 ### `parent_controller`
 
 **Default**: `'::ApplicationController'`

lib/generators/inertia/install/templates/initializer.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 InertiaRails.configure do |config|
-  config.ssr_enabled = ViteRuby.config.ssr_build_enabled
   config.version = ViteRuby.digest
+  config.encrypt_history = true
+  config.always_include_errors_hash = true
 end

lib/inertia_rails/configuration.rb

@@ -26,8 +26,11 @@ class Configuration
       # Used to detect version drift between server and client.
       version: nil,
 
-      # Allows configuring the base controller for StaticController
+      # Allows configuring the base controller for StaticController.
       parent_controller: '::ApplicationController',
+
+      # Whether to include empty `errors` hash to the props when no errors are present.
+      always_include_errors_hash: nil,
     }.freeze
 
     OPTION_NAMES = DEFAULTS.keys.freeze

lib/inertia_rails/controller.rb

@@ -144,7 +144,22 @@ def inertia_configuration
     end
 
     def inertia_shared_data
-      initial_data = session[:inertia_errors].present? ? {errors: session[:inertia_errors]} : {}
+      initial_data =
+        if session[:inertia_errors].present?
+          { errors: session[:inertia_errors] }
+        elsif inertia_configuration.always_include_errors_hash
+          { errors: {} }
+        else
+          if inertia_configuration.always_include_errors_hash.nil?
+            InertiaRails.deprecator.warn(
+              "To comply with the Inertia protocol, an empty errors hash `{errors: {}}` " \
+              "will be included to all responses by default starting with InertiaRails 4.0. " \
+              "To opt-in now, set `config.always_include_errors_hash = true`. " \
+              "To disable this warning, set it to `false`."
+            )
+          end
+          {}
+        end
 
       self.class._inertia_shared_data.filter_map { |shared_data|
         if shared_data.respond_to?(:call)

lib/inertia_rails/renderer.rb

@@ -91,6 +91,11 @@ def merge_props(shared_props, props)
 
     def computed_props
       merged_props = merge_props(shared_data, props)
+      # Always keep errors in the props
+      if merged_props.key?(:errors) && !merged_props[:errors].is_a?(BaseProp)
+        errors = merged_props[:errors]
+        merged_props[:errors] = InertiaRails.always { errors }
+      end
       deep_transform_props(merged_props).tap do |transformed_props|
         transformed_props[:_inertia_meta] = meta_tags if meta_tags.present?
       end

spec/inertia/error_sharing_spec.rb

@@ -1,4 +1,57 @@
 RSpec.describe 'errors shared automatically', type: :request do
+  context 'always_include_errors_hash configuration' do
+    let(:server_version) { 1.0 }
+    let(:headers) { { 'X-Inertia' => true } }
+
+    after { InertiaRails.configure { |c| c.always_include_errors_hash = nil } }
+
+    context 'when always_include_errors_hash is true' do
+      before { InertiaRails.configure { |c| c.always_include_errors_hash = true } }
+
+      it 'includes empty errors hash when no errors present' do
+        get empty_test_path, headers: headers
+        expect(response.body).to include({ errors: {} }.to_json)
+      end
+
+      it 'still includes actual errors when they exist' do
+        post redirect_with_inertia_errors_path, headers: headers
+        get response.headers['Location'], headers: headers
+        expect(response.body).to include({ errors: { uh: 'oh' } }.to_json)
+      end
+    end
+
+    context 'when always_include_errors_hash is false' do
+      before { InertiaRails.configure { |c| c.always_include_errors_hash = false } }
+
+      it 'does not include errors hash when no errors present' do
+        get empty_test_path, headers: headers
+        expect(response.body).not_to include('"errors"')
+      end
+
+      it 'still includes actual errors when they exist' do
+        post redirect_with_inertia_errors_path, headers: headers
+        get response.headers['Location'], headers: headers
+        expect(response.body).to include({ errors: { uh: 'oh' } }.to_json)
+      end
+    end
+
+    context 'when always_include_errors_hash is nil (default)' do
+      before { InertiaRails.configure { |c| c.always_include_errors_hash = nil } }
+
+      it 'shows deprecation warning and does not include empty errors hash' do
+        expect { get empty_test_path, headers: headers }
+          .to output(/To comply with the Inertia protocol/).to_stderr
+        expect(response.body).not_to include('"errors"')
+      end
+
+      it 'still includes actual errors when they exist' do
+        post redirect_with_inertia_errors_path, headers: headers
+        get response.headers['Location'], headers: headers
+        expect(response.body).to include({ errors: { uh: 'oh' } }.to_json)
+      end
+    end
+  end
+
   context 'rendering errors across redirects' do
     let(:server_version){ 1.0 }
     let(:headers){ { 'X-Inertia' => true, 'X-Inertia-Version' => server_version } }
@@ -45,5 +98,27 @@
       expect(response.body).to include(CGI::escape_html({ errors: { uh: 'oh' } }.to_json))
       expect(session[:inertia_errors]).not_to be
     end
+
+    context 'with partial update' do
+      let(:headers) do
+        {
+          'X-Inertia' => true,
+          'X-Inertia-Version' => server_version,
+          'X-Inertia-Partial-Component' => 'EmptyTestComponent',
+          'X-Inertia-Partial-Data' => 'foo',
+        }
+      end
+
+      it 'keeps errors when partial inertia request redirects' do
+        post redirect_with_inertia_errors_path, headers: headers
+        expect(response.headers['Location']).to eq(empty_test_url)
+        expect(session[:inertia_errors]).to include({ uh: 'oh' })
+
+        # Follow the redirect
+        get response.headers['Location'], headers: headers
+        expect(response.body).to include({ errors: { uh: 'oh' } }.to_json)
+        expect(session[:inertia_errors]).not_to be
+      end
+    end
   end
 end