Add error pages for tag limit and pagination errors.

app/controllers/application_controller.rb

@@ -62,9 +62,9 @@ class ApplicationController < ActionController::Base
     when ActionController::UnknownFormat, ActionView::MissingTemplate
       render_error_page(406, exception, message: "#{request.format.to_s} is not a supported format for this page")
     when Danbooru::Paginator::PaginationError
-      render_error_page(410, exception)
+      render_error_page(410, exception, template: "static/pagination_error", message: "You cannot go beyond page #{Danbooru.config.max_numbered_pages}.")
     when Post::SearchError
-      render_error_page(422, exception)
+      render_error_page(422, exception, template: "static/tag_limit_error", message: "You cannot search for more than #{CurrentUser.tag_query_limit} tags at a time.")
     when ApiLimitError
       render_error_page(429, exception)
     when NotImplementedError

app/logical/danbooru/paginator/active_record_extension.rb

@@ -54,7 +54,7 @@ module Danbooru
           page = [page.to_i, 1].max
 
           if page > Danbooru.config.max_numbered_pages
-            raise ::Danbooru::Paginator::PaginationError.new("You cannot go beyond page #{Danbooru.config.max_numbered_pages}. Please narrow your search terms.")
+            raise ::Danbooru::Paginator::PaginationError
           end
 
           extending(NumberedCollectionExtension).limit(records_per_page).offset((page - 1) * records_per_page).tap do |obj|

app/logical/post_query_builder.rb

@@ -122,7 +122,7 @@ class PostQueryBuilder
     relation = read_only ? PostReadOnly.all : Post.all
 
     if q[:tag_count].to_i > Danbooru.config.tag_query_limit
-      raise ::Post::SearchError.new("You cannot search for more than #{Danbooru.config.tag_query_limit} tags at a time")
+      raise ::Post::SearchError
     end
 
     if CurrentUser.safe_mode?

app/views/static/pagination_error.html.erb

@@ -0,0 +1,17 @@
+<h1>Search Error</h1>
+
+<p>
+  <%= @message %>
+
+  <% if CurrentUser.is_platinum? %>
+    Try narrowing your search terms.
+  <% else %>
+    Try narrowing your search terms, or <%= link_to "upgrade your account", new_user_upgrade_path  %> to go beyond page <%= Danbooru.config.max_numbered_pages %>.
+  <% end %>
+</p>
+
+<%= link_to "Go back", :back, rel: "prev" %>
+
+<% content_for(:page_title) do %>
+  Search Error - <%= Danbooru.config.app_name %>
+<% end %>

app/views/static/tag_limit_error.html.erb

@@ -0,0 +1,15 @@
+<h1>Search Error</h1>
+
+<p>
+  <%= @message %>
+
+  <% unless CurrentUser.is_platinum? %>
+    <%= link_to "Upgrade your account", new_user_upgrade_path  %> to search for more tags at once.
+  <% end %>
+</p>
+
+<%= link_to "Go back", :back, rel: "prev" %>
+
+<% content_for(:page_title) do %>
+  Search Error - <%= Danbooru.config.app_name %>
+<% end %>

test/functional/posts_controller_test.rb

@@ -66,6 +66,20 @@ class PostsControllerTest < ActionDispatch::IntegrationTest
           get posts_path, params: {:tags => "1girl solo"}
           assert_response :success
         end
+
+        should "render an error when searching for too many tags" do
+          get posts_path, params: { tags: "1 2 3" }
+
+          assert_response 422
+          assert_select "h1", "Search Error"
+        end
+
+        should "render an error when exceeding the page limit" do
+          get posts_path, params: { page: 1001 }
+
+          assert_response 410
+          assert_select "h1", "Search Error"
+        end
       end
 
       context "with an md5 param" do