Split source map paths as absolute/relative

Author: theodorton

lib/propshaft/compiler/source_mapping_urls.rb

@@ -11,10 +11,11 @@ def compile(asset, input)
 
   private
     def asset_path(source_mapping_url, logical_path)
-      source_mapping_url = ::File.basename(source_mapping_url)
+      source_mapping_url.gsub!(/^(.+\/)?#{url_prefix}\//, "/")
+      source_mapping_path = Pathname.new(source_mapping_url)
 
-      if logical_path.dirname.to_s == "."
-        source_mapping_url
+      if source_mapping_path.absolute?
+        source_mapping_url.sub(/^\//, "")
       else
         logical_path.dirname.join(source_mapping_url).to_s
       end

test/fixtures/assets/mapped/nested/sourceMappingURL-already-prefixed-nested.js

@@ -1 +1 @@
-var fun; //# sourceMappingURL=/assets/sourceMappingURL-already-prefixed-nested.js.map
+var fun; //# sourceMappingURL=/assets/nested/sourceMappingURL-already-prefixed-nested.js.map