Don't add undefined properties when forwarding

Maybe we should keep the nulls.

Author: sebmarkbage

packages/react-client/src/ReactFlightClient.js

@@ -2658,7 +2658,7 @@ function resolveDebugInfo(
     // to initialize it when we need it, we might be inside user code.
     initializeFakeTask(response, componentInfoOrAsyncInfo);
   }
-  if (debugInfo.owner === null && response._debugRootOwner != null) {
+  if (debugInfo.owner == null && response._debugRootOwner != null) {
     const componentInfoOrAsyncInfo: ReactComponentInfo | ReactAsyncInfo =
       // $FlowFixMe: By narrowing `owner` to `null`, we narrowed `debugInfo` to `ReactComponentInfo`
       debugInfo;

packages/react-server/src/ReactFlightServer.js

@@ -3614,18 +3614,24 @@ function outlineComponentInfo(
     'debugTask' | 'debugStack',
   > = {
     name: componentInfo.name,
-    env: componentInfo.env,
     key: componentInfo.key,
-    owner: componentInfo.owner,
   };
+  if (componentInfo.env != null) {
+    // $FlowFixMe[cannot-write]
+    componentDebugInfo.env = componentInfo.env;
+  }
+  if (componentInfo.owner != null) {
+    // $FlowFixMe[cannot-write]
+    componentDebugInfo.owner = componentInfo.owner;
+  }
   if (componentInfo.stack == null && componentInfo.debugStack != null) {
     // If we have a debugStack but no parsed stack we should parse it.
     // $FlowFixMe[cannot-write]
     componentDebugInfo.stack = filterStackTrace(
       request,
       parseStackTrace(componentInfo.debugStack, 1),
     );
-  } else {
+  } else if (componentInfo.stack != null) {
     // $FlowFixMe[cannot-write]
     componentDebugInfo.stack = componentInfo.stack;
   }
@@ -4337,10 +4343,19 @@ function forwardDebugInfo(
             'debugTask' | 'debugStack',
           > = {
             awaited: ioInfo,
-            env: info.env,
-            owner: info.owner,
-            stack: debugStack,
           };
+          if (info.env != null) {
+            // $FlowFixMe[cannot-write]
+            debugAsyncInfo.env = info.env;
+          }
+          if (info.owner != null) {
+            // $FlowFixMe[cannot-write]
+            debugAsyncInfo.owner = info.owner;
+          }
+          if (debugStack != null) {
+            // $FlowFixMe[cannot-write]
+            debugAsyncInfo.stack = debugStack;
+          }
           emitDebugChunk(request, id, debugAsyncInfo);
         }
       } else {