1 files changed, 9 insertions, 0 deletions
diff --git a/node_modules/source-map/lib/source-map-generator.js b/node_modules/source-map/lib/source-map-generator.js
index aff1e7fb2..508bcfbbc 100644
--- a/node_modules/source-map/lib/source-map-generator.js
+++ b/node_modules/source-map/lib/source-map-generator.js
@@ -72,6 +72,15 @@ SourceMapGenerator.fromSourceMap =
       generator.addMapping(newMapping);
     });
     aSourceMapConsumer.sources.forEach(function (sourceFile) {
+      var sourceRelative = sourceFile;
+      if (sourceRoot !== null) {
+        sourceRelative = util.relative(sourceRoot, sourceFile);
+      }
+
+      if (!generator._sources.has(sourceRelative)) {
+        generator._sources.add(sourceRelative);
+      }
+
       var content = aSourceMapConsumer.sourceContentFor(sourceFile);
       if (content != null) {
         generator.setSourceContent(sourceFile, content);