handle sourcemap urls that have already been prefixed with asset path

test cases

Author: tagCincy

lib/propshaft/compiler/source_mapping_urls.rb

@@ -11,6 +11,8 @@ def compile(logical_path, input)
 
   private
     def asset_path(source_mapping_url, logical_path)
+      source_mapping_url.gsub!(/^\/?#{url_prefix}\//, "")
+
       if logical_path.dirname.to_s == "."
         source_mapping_url
       else
@@ -19,7 +21,7 @@ def asset_path(source_mapping_url, logical_path)
     end
 
     def source_mapping_url(resolved_path, comment_start, comment_end)
-      if asset = assembly.load_path.find(resolved_path)
+      if (asset = assembly.load_path.find(resolved_path))
         "#{comment_start}# sourceMappingURL=#{url_prefix}/#{asset.digested_path}#{comment_end}"
       else
         Propshaft.logger.warn "Removed sourceMappingURL comment for missing asset '#{resolved_path}' from #{resolved_path}"

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

@@ -0,0 +1 @@
+var fun; //# sourceMappingURL=/assets/sourceMappingURL-already-prefixed-nested.js.map

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

@@ -0,0 +1 @@
+var fun; //# sourceMappingURL=/assets/sourceMappingURL-already-prefixed.js.map

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

@@ -53,6 +53,13 @@ class Propshaft::Compiler::SourceMappingUrlsTest < ActiveSupport::TestCase
                  compile_asset(find_asset("sourceMappingURL-outside-comment.css", fixture_path: "mapped"))
   end
 
+  test "sourceMapURL is already prefixed with url_prefix" do
+    assert_match %r{//# sourceMappingURL=/assets/sourceMappingURL-already-prefixed.js-[a-z0-9]{40}\.map},
+                 compile_asset(find_asset("sourceMappingURL-already-prefixed.js", fixture_path: "mapped"))
+    assert_match %r{//# sourceMappingURL=/assets/nested/sourceMappingURL-already-prefixed-nested.js-[a-z0-9]{40}\.map},
+                 compile_asset(find_asset("nested/sourceMappingURL-already-prefixed-nested.js", fixture_path: "mapped"))
+  end
+
   test "relative url root" do
     @options.relative_url_root = "/url-root"