Update SourceWrapperNotFoundError handling

lib/slimmer/processors/body_inserter.rb

@@ -10,7 +10,17 @@ def filter(src, dest)
       source_markup = src.at_css(@source_selector)
       destination_markup = dest.at_css(@destination_selector)
 
-      raise(Slimmer::SourceWrapperNotFoundError, "Source wrapper div not found", caller) if source_markup.nil? && wrapper_check?
+      if source_markup.nil? && wrapper_check?
+        raise(Slimmer::SourceWrapperNotFoundError, <<~END_STRING, caller)
+          Slimmer did not find the wrapper div in the source HTML.
+          The following cause can be safely ignored, other need
+          to be investigated. One possible cause is that the
+          requested format was different from HTML e.g. JavaScript,
+          but the action only supports the HTML template and layout.
+          Rails only applies layouts matching the requested format,
+          so the layout was not applied.
+        END_STRING
+      end
 
       css_classes = []
       css_classes << source_markup.attributes["class"].to_s.split(/ +/) if source_markup.has_attribute?("class")

lib/slimmer/skin.rb

@@ -100,7 +100,6 @@ def process(processors, body, template, _rack_env)
     end
 
     def success(source_request, response, body)
-      original_body = body.dup
       wrapper_id = options[:wrapper_id] || "wrapper"
       template_wrapper_id = "wrapper" # All templates in Static use `#wrapper`
 
@@ -123,12 +122,6 @@ def success(source_request, response, body)
 
       template_name = response.headers[Headers::TEMPLATE_HEADER] || "gem_layout"
       process(processors, body, template(template_name), source_request.env)
-    rescue SourceWrapperNotFoundError => e
-      message = "#{e.message} "\
-                "at: #{source_request.base_url}#{source_request.path} "\
-                "length: #{original_body.to_s.length} "\
-                "body: #{original_body.to_s[0..2000]}"
-      raise SourceWrapperNotFoundError, message, caller
     end
   end
 end