Fix sourceMappingURL in compressed/minified files

lib/propshaft/compiler/source_mapping_urls.rb

@@ -3,10 +3,10 @@
 require "propshaft/compiler"
 
 class Propshaft::Compiler::SourceMappingUrls < Propshaft::Compiler
-  SOURCE_MAPPING_PATTERN = %r{^(//|/\*)# sourceMappingURL=(.+\.map)}
+  SOURCE_MAPPING_PATTERN = %r{(//|/\*)# sourceMappingURL=(.+\.map)((?:\s\*/)?(?:\r?\n)*)\Z}
 
   def compile(logical_path, input)
-    input.gsub(SOURCE_MAPPING_PATTERN) { source_mapping_url(asset_path($2, logical_path), $1) }
+    input.gsub(SOURCE_MAPPING_PATTERN) { source_mapping_url(asset_path($2, logical_path), $1, $3) }
   end
 
   private
@@ -18,12 +18,12 @@ def asset_path(source_mapping_url, logical_path)
       end
     end
 
-    def source_mapping_url(resolved_path, comment)
+    def source_mapping_url(resolved_path, comment_begin, comment_end)
       if asset = assembly.load_path.find(resolved_path)
-        "#{comment}# sourceMappingURL=#{url_prefix}/#{asset.digested_path}"
+        "#{comment_begin}# sourceMappingURL=#{url_prefix}/#{asset.digested_path}#{comment_end}"
       else
         Propshaft.logger.warn "Removed sourceMappingURL comment for missing asset '#{resolved_path}' from #{resolved_path}"
-        comment
+        "#{comment_begin}#{comment_end}"
       end
     end
 end

test/fixtures/assets/mapped/compressed.css

@@ -0,0 +1 @@
+.class{color:green}/*# sourceMappingURL=compressed.css.map */

test/propshaft/compiler/source_mapping_urls_test.rb

@@ -25,6 +25,16 @@ class Propshaft::Compiler::SourceMappingUrlsTest < ActiveSupport::TestCase
                  compile_asset(find_asset("nested/another-source.js", fixture_path: "mapped"))
   end
 
+  test "matching source map in css compressed mode" do
+    assert_match %r{/\*# sourceMappingURL=/assets/compressed.css-[a-z0-9]{40}\.map},
+                 compile_asset(find_asset("compressed.css", fixture_path: "mapped"))
+  end
+
+  test "matching source map in js minified mode" do
+    assert_match %r{//# sourceMappingURL=/assets/minified.js-[a-z0-9]{40}\.map},
+                 compile_asset(find_asset("minified.js", fixture_path: "mapped"))
+  end
+
   test "missing source map" do
     assert_no_match %r{sourceMappingURL},
                     compile_asset(find_asset("sourceless.js", fixture_path: "mapped"))
@@ -42,7 +52,7 @@ class Propshaft::Compiler::SourceMappingUrlsTest < ActiveSupport::TestCase
                  compile_asset(find_asset("sourceMappingURL-outside-comment.css", fixture_path: "mapped"))
   end
 
-  test "sourceMappingURL not at the beginning of the line should be left alone" do
+  test "sourceMappingURL not at the end of the source should be left alone" do
     assert_match %r{sourceMappingURL=sourceMappingURL-not-at-start.css.map},
                  compile_asset(find_asset("sourceMappingURL-not-at-start.css", fixture_path: "mapped"))
   end