Add integration test for original sourcesContent through transformations

packages/core/integration-tests/test/integration/sourcemap-original-sourcecontents/.babelrc

@@ -0,0 +1,3 @@
+{
+  "presets": ["@babel/preset-react", "@babel/preset-flow"]
+}

packages/core/integration-tests/test/integration/sourcemap-original-sourcecontents/index.js

@@ -0,0 +1,14 @@
+// @flow
+
+import * as React from "react";
+import * as ReactDOM from "react-dom";
+
+type Props = {|
+  bar: string,
+|};
+
+function App(props: Props) {
+  return <div>{props.bar}</div>;
+}
+
+ReactDOM.render(<App bar="bar" />, document.getElementById("root"));

packages/core/integration-tests/test/sourcemaps.js

@@ -1286,4 +1286,49 @@ describe('sourcemaps', function() {
       sourcePath,
     });
   });
+
+  it('carries sourcesContent from the original sources through multiple transformations (babel and swc)', async () => {
+    let b = await bundle(
+      path.join(
+        __dirname,
+        'integration/sourcemap-original-sourcecontents/index.js',
+      ),
+      {
+        defaultTargetOptions: {
+          shouldScopeHoist: true,
+        },
+      },
+    );
+
+    let filename = b.getBundles()[0].filePath;
+    let raw = await outputFS.readFile(filename, 'utf8');
+
+    let mapUrlData = await loadSourceMapUrl(outputFS, filename, raw);
+    if (!mapUrlData) {
+      throw new Error('Could not load map');
+    }
+    let map = mapUrlData.map;
+
+    let sourceMap = new SourceMap('/');
+    sourceMap.addRawMappings(map);
+    let sourceContent = map.sourcesContent[0];
+    let sourcePath = './index.js';
+
+    checkSourceMapping({
+      map: sourceMap,
+      source: sourceContent,
+      generated: raw,
+      str: 'bar="bar"' /* from jsx: <App bar="bar" /> */,
+      generatedStr: 'bar: "bar"',
+      sourcePath,
+    });
+
+    checkSourceMapping({
+      map: sourceMap,
+      source: sourceContent,
+      generated: raw,
+      str: 'document.getElementById(',
+      sourcePath,
+    });
+  });
 });