Issue when we use realmContext and Realm.config at same time

[somasekharkakarla]

How frequently does the bug occur?

Always

Description

Hi @kneth and @takameyer ,

Here is a problem i have found with realm.

@realm/react is hook i am using in view components to for CURD operations.
I am using Realm.config in RealmMangerClass for listening the changes in old fashion and changed data was updated to server. I am writing the response from server to realm. These are all happing in RealmManager

In this way. i am initialising same config at two place. createRealmContext at App.js and Realm.open in RealmManager class

In random case both (RealmContext and Realm.open) > write to db.
This is causing two errors:

1. realm already in write transaction
2. [Error: Exception in HostFunction: Accessing object of type Tasks which has been invalidated or deleted]

Is there any way i can get reference of realm from createRealmContext. where i can use it in RealmManager class instead of initialising again in Class

I want to use hook on UI and listen to listener and do CURD operations in old fashion at same time.

Stacktrace & log output

No response

Can you reproduce the bug?

Always

Reproduction Steps

No response

Version

11.3.1

What services are you using?

Local Database only

Are you using encryption?

No

Platform OS and version(s)

android 13

Build environment

Which debugger for React Native: ..

Cocoapods version

No response

[takameyer]

@somasekharkakarla The workflow you described is supported, so feel free to reinitialize it in your class. As long as you use the same configuration passed to createRealmContext and new Realm(), the result will be a shared instance of the same Realm. Even if you were to get the same realm from createRealmContext and have it in your RealmManager, the result would likely be the same.

Let's address the errors you are having:

realm already in write transaction

There is a member variable on the realm instance called isInTransaction. I would recommend using this in the areas that have been crashing to help ensure you do not come into conflict with realm transactions. Since JS is running on a single thread, using setImmediate can be helpful in ensuring the current write transaction finishes before the next happens by pushing it into the event loop:

   if (realm.isInTransaction) {
      setImmediate(() => {
        realm.write(() => {
          // Do something
        })
      })

[Error: Exception in HostFunction: Accessing object of type Tasks which has been invalidated or deleted]

This can happen if you are holding onto a realm object that isn't managed by the hooks (useObject, useQuery). The hooks will automatically re-render and nullify any invalid objects. If you are doing some logic with RealmManager to look at a held instance of some object, then I would recommend checking the member variable isValid on the object.

Let me know if this helps!

[somasekharkakarla]

Hi @takameyer,

Thank for the response. isInTransaction is really helpful. Tell me something,
I am using a hook taskObj = useObject('Task', uid)
i delete it from backend from a async call. But i am still in same component. Then i am getting
[Error: Exception in HostFunction: Accessing object of type Tasks which has been invalidated or deleted]
i used isVaild() it says undefined and crash
is there anyway we can know the obj is deleted.

[somasekharkakarla]

Hi @takameyer ,
i'm pleasing you looking into this feature request #5864. I think it will give more power to developers

[takameyer]

@somasekharkakarla Can you verify that the crash is happening within the component, or somewhere else? useObject will automatically return null when the object is not valid.

[somasekharkakarla]

Hi @takameyer . i will reverify it again.

[somasekharkakarla]

Hi @takameyer ,

i reverified. crash is happening at useObject only.

try {
taskObj = useObject('Tasks', task?.uid);
taskObj.addListener((task:any, changes:any) =>{
if(changes.deleted){
navigation.goBack();
}
})
} catch (e) {
console.error(" taskObj.addListener Error", e)

I am deleting this task by async process. while deleting i am staying in same screen.

[takameyer]

@somasekharkakarla The code sample is a bit confusing. useObject should not be called within a try/catch and addListener should be inside of a useEffect, otherwise, you will be adding an additional listener on every re-render of this component.
Can you possibly provide a sample repo that replicates the crash you are getting?

[somasekharkakarla]

Hi @takameyer , sure. i create separate repo for that share you soon.

[kneth]

@somasekharkakarla Sounds good. We will leave the issue open and you can post a link to the repo once you are ready.

[sync-by-unito]

➤ takameyer commented:

Closing due to inactivity. Please reopen when you can provide more information.