Restrict SOURCE_MAPPING_PATTERN to only match leading comments

The `sourceMappingURL` comments always appear at the beginning of the line, so we can ignore any comments that appear later in a line when searching for comments to replace.
rails · Nov 23, 2021 · 1dd7799 · 1dd7799
1 parent d319486
commit 1dd7799
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Showing 3 changed files with 9 additions and 1 deletion.
diff --git a/lib/propshaft/compilers/source_mapping_urls.rb b/lib/propshaft/compilers/source_mapping_urls.rb
@@ -3,7 +3,7 @@
 class Propshaft::Compilers::SourceMappingUrls
   attr_reader :assembly
 
-  SOURCE_MAPPING_PATTERN = %r{(//|/\*)# sourceMappingURL=(.*\.map)}
+  SOURCE_MAPPING_PATTERN = %r{^(//|/\*)# sourceMappingURL=(.*\.map)}
 
   def initialize(assembly)
     @assembly = assembly

diff --git a/test/fixtures/assets/mapped/sourceMappingURL-not-at-start.css b/test/fixtures/assets/mapped/sourceMappingURL-not-at-start.css
@@ -0,0 +1,3 @@
+.class {
+  color: green; /*# sourceMappingURL=sourceMappingURL-not-at-start.css.map */
+}
diff --git a/test/propshaft/compilers/source_mapping_urls_test.rb b/test/propshaft/compilers/source_mapping_urls_test.rb
@@ -39,4 +39,9 @@ class Propshaft::Compilers::SourceMappingUrlsTest < ActiveSupport::TestCase
     assert_match %r{sourceMappingURL=sourceMappingURL-outside-comment.css.map},
                  @assembly.compilers.compile(find_asset("sourceMappingURL-outside-comment.css", fixture_path: "mapped"))
   end
+
+  test "sourceMappingURL not at the beginning of the line should be left alone" do
+    assert_match %r{sourceMappingURL=sourceMappingURL-not-at-start.css.map},
+                 @assembly.compilers.compile(find_asset("sourceMappingURL-not-at-start.css", fixture_path: "mapped"))
+  end
 end