feat: engine-scoped 404 and 500 error pages

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- Engine-scoped error pages — 404 (`ActiveRecord::RecordNotFound`) and 500 (unhandled `StandardError` in production) now render within the dashboard chrome instead of falling through to the host app's error pages; in development `consider_all_requests_local` keeps the standard Rails debug page
 - Covering indexes added to dummy app schema — `solid_queue_jobs (finished_at, created_at)` for the slow-job scan; `(queue_name, created_at)` on `solid_queue_scheduled_executions` and `solid_queue_blocked_executions` (both previously lacked a queue-name index)
 - Install generator — `rails generate solid_stack_web:install` creates `config/initializers/solid_stack_web.rb` with every config option documented inline and injects the mount line into `config/routes.rb`
 - `SolidStackWeb.mount_path` — returns the path at which the engine is mounted in the host app, derived automatically from routes; use `link_to "Dashboard", SolidStackWeb.mount_path` to link to the dashboard without hardcoding the path

ROADMAP.md

@@ -11,7 +11,6 @@ The path to v1.0.0 is staged: first achieve feature parity with `solid_queue_das
 > _Make it easy to adopt and easy to contribute to._
 
 ### Remaining
-- **Error pages** — engine-scoped 404/500 views so errors stay within the dashboard chrome
 - **Changelog-driven upgrade notes** — `UPGRADING.md` for any breaking configuration changes
 
 ---

app/controllers/solid_stack_web/application_controller.rb

@@ -9,6 +9,13 @@ class ApplicationController < ActionController::Base
     before_action :authenticate!
     around_action :with_database_connection
 
+    rescue_from StandardError do |exception|
+      raise exception if Rails.application.config.consider_all_requests_local
+      render_internal_server_error
+    end
+
+    rescue_from ActiveRecord::RecordNotFound, with: :render_not_found
+
     helper_method :current_section
 
     private
@@ -43,5 +50,13 @@ def authenticate!
     def request_basic_auth
       request_http_basic_authentication("Solid Stack Dashboard")
     end
+
+    def render_not_found
+      render "solid_stack_web/errors/not_found", status: :not_found
+    end
+
+    def render_internal_server_error
+      render "solid_stack_web/errors/internal_server_error", status: :internal_server_error
+    end
   end
 end

app/views/solid_stack_web/errors/internal_server_error.html.erb

@@ -0,0 +1,8 @@
+<div class="sqw-page-header">
+  <h1 class="sqw-page-title">Something Went Wrong</h1>
+</div>
+
+<div class="sqw-empty">
+  <p class="sqw-empty__title">500 &mdash; An unexpected error occurred.</p>
+  <p class="sqw-empty__hint"><%= link_to "Back to Dashboard", root_path, class: "sqw-btn sqw-btn--secondary" %></p>
+</div>

app/views/solid_stack_web/errors/not_found.html.erb

@@ -0,0 +1,8 @@
+<div class="sqw-page-header">
+  <h1 class="sqw-page-title">Not Found</h1>
+</div>
+
+<div class="sqw-empty">
+  <p class="sqw-empty__title">404 &mdash; The record you&rsquo;re looking for doesn&rsquo;t exist or has been removed.</p>
+  <p class="sqw-empty__hint"><%= link_to "Back to Dashboard", root_path, class: "sqw-btn sqw-btn--secondary" %></p>
+</div>

spec/requests/solid_stack_web/errors_spec.rb

@@ -0,0 +1,40 @@
+require "rails_helper"
+
+RSpec.describe "Error pages", type: :request do
+  let(:engine_root) { "/solid_stack" }
+
+  describe "404 Not Found" do
+    it "renders the engine 404 page when a record is not found" do
+      get "#{engine_root}/jobs/99999999"
+      expect(response).to have_http_status(:not_found)
+      expect(response.body).to include("Not Found")
+      expect(response.body).to include("404")
+    end
+
+    it "renders within the dashboard chrome" do
+      get "#{engine_root}/jobs/99999999"
+      expect(response.body).to include("sqw-header")
+      expect(response.body).to include("Back to Dashboard")
+    end
+  end
+
+  describe "500 Internal Server Error" do
+    before do
+      allow(Rails.application.config).to receive(:consider_all_requests_local).and_return(false)
+      allow_any_instance_of(SolidStackWeb::JobsController).to receive(:index).and_raise(StandardError, "test error")
+    end
+
+    it "renders the engine 500 page on an unhandled error" do
+      get "#{engine_root}/jobs"
+      expect(response).to have_http_status(:internal_server_error)
+      expect(response.body).to include("Something Went Wrong")
+      expect(response.body).to include("500")
+    end
+
+    it "renders within the dashboard chrome" do
+      get "#{engine_root}/jobs"
+      expect(response.body).to include("sqw-header")
+      expect(response.body).to include("Back to Dashboard")
+    end
+  end
+end