fix(node): Don't overwrite local variables for re-thrown errors

dev-packages/node-integration-tests/suites/public-api/LocalVariables/local-variables-rethrow.js

@@ -0,0 +1,45 @@
+/* eslint-disable no-unused-vars */
+const Sentry = require('@sentry/node');
+const { loggingTransport } = require('@sentry-internal/node-integration-tests');
+
+Sentry.init({
+  dsn: 'https://[email protected]/1337',
+  includeLocalVariables: true,
+  transport: loggingTransport,
+});
+
+class Some {
+  two(name) {
+    throw new Error('Enough!');
+  }
+}
+
+function one(name) {
+  const arr = [1, '2', null];
+  const obj = {
+    name,
+    num: 5,
+  };
+  const bool = false;
+  const num = 0;
+  const str = '';
+  const something = undefined;
+  const somethingElse = null;
+
+  const ty = new Some();
+
+  ty.two(name);
+}
+
+setTimeout(() => {
+  try {
+    try {
+      one('some name');
+    } catch (e) {
+      const more = 'here';
+      throw e;
+    }
+  } catch (e) {
+    Sentry.captureException(e);
+  }
+}, 1000);

dev-packages/node-integration-tests/suites/public-api/LocalVariables/test.ts

@@ -78,6 +78,14 @@ conditionalTest({ min: 18 })('LocalVariables integration', () => {
     });
   });
 
+  conditionalTest({ min: 20 })('Node v20+', () => {
+    test('Should retain original local variables when error is re-thrown', done => {
+      createRunner(__dirname, 'local-variables-rethrow.js')
+        .expect({ event: EXPECTED_LOCAL_VARIABLES_EVENT })
+        .start(done);
+    });
+  });
+
   test('Includes local variables for caught exceptions when enabled', done => {
     createRunner(__dirname, 'local-variables-caught.js').expect({ event: EXPECTED_LOCAL_VARIABLES_EVENT }).start(done);
   });

packages/node/src/integrations/local-variables/worker.ts

@@ -118,7 +118,9 @@ async function handlePaused(
   // We write the local variables to a property on the error object. These can be read by the integration as the error
   // event pass through the SDK event pipeline
   await session.post('Runtime.callFunctionOn', {
-    functionDeclaration: `function() { this.${LOCAL_VARIABLES_KEY} = ${JSON.stringify(frames)}; }`,
+    functionDeclaration: `function() { this.${LOCAL_VARIABLES_KEY} = this.${LOCAL_VARIABLES_KEY} || ${JSON.stringify(
+      frames,
+    )}; }`,
     silent: true,
     objectId,
   });
@@ -156,8 +158,10 @@ async function startDebugger(): Promise<void> {
           }, 1_000);
         }
       },
-      _ => {
-        // ignore any errors
+      async _ => {
+        if (isPaused) {
+          await session.post('Debugger.resume');
+        }
       },
     );
   });