fix: rescue MissingAssetError with placeholder image

app/helpers/application_helper.rb

@@ -1,6 +1,37 @@
 # frozen_string_literal: true
 
 module ApplicationHelper
+  # Images
+  #
+  # Fallback image shown when a record-keyed asset (e.g. store/tool images
+  # named after the record) is missing.
+  PLACEHOLDER_IMAGE = 'placeholder.png'
+
+  # Render an image_tag that falls back to PLACEHOLDER_IMAGE when the asset is
+  # missing, instead of raising Propshaft::MissingAssetError and 500-ing the
+  # whole page. Falls back to nothing if even the placeholder is absent.
+  def safe_image_tag(source, options = {})
+    image_tag(source, options)
+  rescue Propshaft::MissingAssetError
+    begin
+      image_tag(PLACEHOLDER_IMAGE, options)
+    rescue Propshaft::MissingAssetError
+      nil
+    end
+  end
+
+  # asset_path that falls back to the placeholder (then nil) instead of raising,
+  # so it is safe to build data attributes (e.g. image_url) for the same source.
+  def safe_asset_path(source)
+    asset_path(source)
+  rescue Propshaft::MissingAssetError
+    begin
+      asset_path(PLACEHOLDER_IMAGE)
+    rescue Propshaft::MissingAssetError
+      nil
+    end
+  end
+
   # Flash
   #
   # Map flash categories to css classes.

app/views/store/items/_item.html.erb

@@ -16,8 +16,8 @@
 </style>
 
 <div class="item-card">
-  <%= image_tag "store_images/#{item.name}.png",
-                style: 'height: 80px; object-fit: contain;' %>
+  <%= safe_image_tag "store_images/#{item.name}.png",
+                     style: 'height: 80px; object-fit: contain;' %>
   <div class="text"><%= link_to item.name, item %></div>
   <div class="text"><%= number_to_currency item.price %></div>
   <%= link_to t('.add_to_cart', default: t('helpers.links.add_to_cart')),

app/views/store/items/show.html.erb

@@ -5,12 +5,9 @@
 
 <div class="content">
   <h1><%= @store_item.name %></h1>
-  <% begin %>
-    <dt>
-      <%= image_tag("store_images/#{@store_item.name}.png", id: "item-image-#{@store_item.name}", class: 'item-image', data: { item_name: @store_item.name, image_url: asset_path("store_images/#{@store_item.name}.png") }, size: '70x70') %>
-    </dt>
-  <% rescue %>
-  <% end %>
+  <dt>
+    <%= safe_image_tag("store_images/#{@store_item.name}.png", id: "item-image-#{@store_item.name}", class: 'item-image', data: { item_name: @store_item.name, image_url: safe_asset_path("store_images/#{@store_item.name}.png") }, size: '70x70') %>
+  </dt>
   <br/>
   <dt><strong>Price:</strong></dt>
   <dd><%= number_to_currency @store_item.price %></dd>

app/views/tool_types/show.html.erb

@@ -5,12 +5,9 @@
 
 <div class="content">
   <h1><%= @tool_type.name %></h1>
-  <% begin %>
-    <dt>
-      <%= image_tag("tool_images/#{@tool_type.name}.png", id: "item-image-#{@tool_type.name}", class: 'item-image', data: { item_name: @tool_type.name, image_url: asset_path("tool_images/#{@tool_type.name}.png") }, size: '70x70') %>
-    </dt>
-  <% rescue %>
-  <% end %>
+  <dt>
+    <%= safe_image_tag("tool_images/#{@tool_type.name}.png", id: "item-image-#{@tool_type.name}", class: 'item-image', data: { item_name: @tool_type.name, image_url: safe_asset_path("tool_images/#{@tool_type.name}.png") }, size: '70x70') %>
+  </dt>
   <br/>
   <% if can?(:update, @tool_type) %>
     <%= link_to t('.edit', default: t('helpers.links.edit')),