Error "Malformed calls from JS: field sizes are different" (caused by "Cannot freeze") occurs on 0.60.5

[mcuelenaere]

When running RN 0.60.5 with V8, in development mode the "Malformed calls from JS: field sizes are different" error gets triggered for our code.

When investigating, this seems to be caused by JS trying to freeze the params that are being passed to the bridge at https://github.com/facebook/react-native/blob/master/Libraries/BatchedBridge/MessageQueue.js#L313.

Object.freeze() throws an error with the unhelpful message "Cannot freeze".
When JSONifying the particular object that is being froze, this is what I see: [{"size":228,"offset":0,"blobId":"f7ece23d-646d-4e09-ba54-0e855932ed26","__collector":{}},"UTF-8",22900,22901].

My hypothesis is that V8 is somehow unable to freeze this particular blob object, while this was possible in JSC/Hermes.

I'll workaround the issue by catching the error and ignoring it (since this is only trying to help the developer and not a strict requirement), but this information might be useful to others and/or this issue might want to be looked into.

[mcuelenaere]

This is the diff we're using in our react-native fork:

diff --git a/Libraries/BatchedBridge/MessageQueue.js b/Libraries/BatchedBridge/MessageQueue.js
index 8fce2a7e67..afbf514103 100644
--- a/Libraries/BatchedBridge/MessageQueue.js
+++ b/Libraries/BatchedBridge/MessageQueue.js
@@ -284,8 +284,14 @@ class MessageQueue {
         JSON.stringify(params, replacer),
       );

-      // The params object should not be mutated after being queued
-      deepFreezeAndThrowOnMutationInDev((params: any));
+      try {
+        // The params object should not be mutated after being queued
+        deepFreezeAndThrowOnMutationInDev((params: any));
+      } catch (err) {
+        // This is not a blocking issue, show a warning but continue executing
+        // (see https://github.com/Kudo/react-native-v8/issues/27 for more context)
+        console.warn('Cannot freeze: ' + JSON.stringify(params, replacer));
+      }
     }
     this._queue[PARAMS].push(params);

[Kudo]

Thanks for the briefly information, I will try to find the root cause accordingly.

[Kudo]

@mcuelenaere Do you mind to provide blob data to be Object.freeze()?
You could try to add `console.log' in MessageQueue.js.

[mcuelenaere]

@Kudo

this is the stacktrace:

TypeError: Cannot freeze
    at Function.freeze (<anonymous>)
    at deepFreezeAndThrowOnMutationInDev (http://localhost:8081/index.bundle?platform=android&dev=true&minify=false:2460:14)
    at deepFreezeAndThrowOnMutationInDev (http://localhost:8081/index.bundle?platform=android&dev=true&minify=false:2467:11)
    at deepFreezeAndThrowOnMutationInDev (http://localhost:8081/index.bundle?platform=android&dev=true&minify=false:2467:11)
    at MessageQueue.enqueueNativeCall (http://localhost:8081/index.bundle?platform=android&dev=true&minify=false:2116:11)
    at http://localhost:8081/index.bundle?platform=android&dev=true&minify=false:1688:25
    at tryCallTwo (http://localhost:8081/index.bundle?platform=android&dev=true&minify=false:24504:7)
    at doResolve (http://localhost:8081/index.bundle?platform=android&dev=true&minify=false:24668:15)
    at new Promise (http://localhost:8081/index.bundle?platform=android&dev=true&minify=false:24527:5)
    at Object.fn [as readAsText] (http://localhost:8081/index.bundle?platform=android&dev=true&minify=false:1687:16)

and these are JSON.stringify() of some blobs:

[{"size":228,"offset":0,"blobId":"a48e5968-11a3-4692-a36c-746a383a4216","__collector":{}},"UTF-8",25890,25891]
[{"size":3340,"offset":0,"blobId":"6aa40fc3-5415-48cf-9d6b-1aab4f614edb","__collector":{}},"UTF-8",44036,44037]
[{"size":228,"offset":0,"blobId":"a48e5968-11a3-4692-a36c-746a383a4216","__collector":{}},"UTF-8",25890,25891]

My hypothesis is that the __collector member variable is the issue, which is probably a reference to a native object created at https://github.com/facebook/react-native/blob/master/ReactAndroid/src/main/java/com/facebook/react/modules/blob/jni/BlobCollector.cpp#L54

[Kudo]

@mcuelenaere Could you double confirm react-native version is 0.60.5 and react-native-v8 version is 0.60.5-patch.0?
As the BlobCollector did not land on RN 0.60 yet, the code path should not hit on the BlobCollector you mentioned.
One possibility is that you use wrong react-native-v8 version, e.g. 0.61.1-patch.0.

For the V8 problem, V8 cannot do Object.freeze on object with interceptors.
react-native-v8 did add interceptors on RN JSI hosted object.
I will test Blob on RN 0.61 anyway and see if I could overcome the issue.
Thanks for your information.

[mcuelenaere]

@Kudo yes, that's because we use a fork of 0.60.5 with some fixes from 0.61 cherry picked on top (see https://github.com/getdelta/react-native/commits/0.60-patched%2Bv8 )

[Kudo]

@mcuelenaere Thanks, I was able to reproduce the problem from your forked and the code.

const TestCase = async () => {
  const resp = await fetch('http://www.africau.edu/images/default/sample.pdf', {
    method: 'GET',
  });
  const respBlob = await resp.blob();
  await AsyncStorage.setItem('foo', respBlob);
  console.log('respBlob', respBlob);
};

Passing an JSI hosted object through RN bridge will cause the problem.

Unfortunately, I have no proper solution in the mean time.
That is V8's design not to support Object.freeze for objects with interceptors and it is somehow right.
Please let me think a proper idea for a while.

Thank you.

[Kudo]

@mcuelenaere I've sent a PR to address the issue.
facebook/react-native#27013
Since you have forked RN, you may able to apply the patch first in your repo and see if the fix helps.

[winseyli]

Hi there. I have the same problem with RN version 0.61.4 (react-native-v8 version 0.61.4-patch.1)
Issue can be reproduced by response.json() after fetch

[Kudo]

@mcuelenaere @winseyli Considering the PR not updated for a while, I finally decide to workaround the issue in V8.
Please try to use v8-android@7.8.2 / v8-android-nointl@7.8.2 and see if this could solve your problems. Thank you.

[winseyli]

@Kudo Thanks it works 👍

[gmaclennan]

Thanks for taking the time to fix this @Kudo, the update works and our app is working again!