Attempt to access a relationship collection method on that entity

Oct 13, 2025 by pynkocean.com 31 views

[BUG]: Undefined Entity Relationship When Accessing Derived Collections

Description

When creating a new entity and immediately attempting to access a derived collection through its accessor method, an error occurs: Get property "[relationship_name]" from Entity "[EntityName]" failed: Value is required but received null or undefined. This issue appears to be a race condition or initialization problem in how the SDK handles entity relationships, particularly after entity creation.

Steps to Reproduce

To reproduce this issue, follow these steps:

Create a new entity: Create a new entity, for example, MRUser.
Save it with await store.upsert(user): Save the newly created entity using the upsert method provided by the SDK.
Attempt to access a relationship collection method on that entity: Immediately attempt to access a relationship collection method on the newly created entity, for example, user.staked_balances().

Error Message

The error message that occurs when attempting to access the derived collection is as follows:

Get property "staked_balances" from Entity "MRUser" failed: Value is required but received null or undefined
Error: Get property "staked_balances" from Entity "MRUser" failed: Value is required but received null or undefined
    at handleError (/tmp/sentio/cache/983799004/sentio/V5KQrOvw/node_modules/@sentio/sdk/src/store/decorators.ts:27:11)
    at D0.idGetter (/tmp/sentio/cache/983799004/sentio/V5KQrOvw/node_modules/@sentio/sdk/src/store/decorators.ts:40:18)
    at D0.get (/tmp/sentio/cache/983799004/sentio/V5KQrOvw/node_modules/@sentio/sdk/src/store/decorators.ts:53:34)
    at D0.staked_balances (/tmp/sentio/cache/983799004/sentio/src/schema/schema.rewards.ts:288:17)
    at getOrCreateUserStakedBalance (/tmp/sentio/cache/983799004/sentio/src/processors/multi-rewards-processor.ts:909:40)

Expected Behavior

After creating and persisting a new entity, accessing its relationship collections (even empty ones) should work correctly. The collection accessor should return an empty array rather than throwing an error.

Environment Information

Sentio SDK Version: The latest version as of March 2025.
GraphQL Schema: Contains @derivedFrom relationships (see attached schema.rewards.graphql).
Runtime Environment: Sentio Cloud Production.

Current Workaround

We've implemented a workaround by directly manipulating the ID arrays instead of using the relationship accessors:

// Original code that triggers the bug
const staked_balances = await user.staked_balances();
staked_balances.push(balance);
user._staked_balances = Promise.resolve(staked_balances);

// Workaround
user.staked_balancesIDs.push(balance.id);
await store.upsert(user);

This workaround is implemented in the branch undefined-MRUser-bug-fix in the PR below (to reproduce the error simply undo the workaround in the PR below and upload the processor with pnpm upload):

https://github.com/Canopyxyz/sentio-processors/pull/7

Additional Notes

Inconsistent behavior: This issue appears to be inconsistent between local development/testing and production environments.
Specific to @derivedFrom relationships: The problem specifically manifests with @derivedFrom relationships.
SDK initialization issue: We suspect the SDK might not be properly initializing the internal promises for these derived collections upon entity creation.

Possible Causes

The possible causes of this issue are:

Race condition: A race condition might occur when accessing the derived collection before it is properly initialized.
Initialization issue: The SDK might not be properly initializing the internal promises for the derived collections upon entity creation.

Solution

To solve this issue, we need to ensure that the derived collections are properly initialized before accessing them. This can be achieved by implementing a mechanism to wait for the initialization of the derived collections before accessing them.

Implementation

To implement this solution, we can modify the SDK to include a mechanism to wait for the initialization of the derived collections. This can be achieved by adding a wait method to the entity that returns a promise that resolves when the derived collections are initialized.

// Modified SDK implementation
class Entity {
  // ...
  async wait() {
    // Wait for the initialization of the derived collections
    await this._derivedCollectionsInitialized;
  }
}

// Modified entity implementation
class MRUser extends Entity {
  // ...
  async staked_balances() {
    // Wait for the initialization of the derived collections
    await this.wait();
    // Return the staked balances
    return this._staked_balances;
  }
}

By implementing this solution, we can ensure that the derived collections are properly initialized before accessing them, and the error occurs when accessing the derived collection is resolved.
[BUG]: Undefined Entity Relationship When Accessing Derived Collections - Q&A

Q: What is the issue with accessing derived collections in the Sentio SDK?

A: When creating a new entity and immediately attempting to access a derived collection through its accessor method, an error occurs: Get property "[relationship_name]" from Entity "[EntityName]" failed: Value is required but received null or undefined. This issue appears to be a race condition or initialization problem in how the SDK handles entity relationships, particularly after entity creation.

Q: What are the steps to reproduce this issue?

A: To reproduce this issue, follow these steps:

Create a new entity: Create a new entity, for example, MRUser.
Save it with await store.upsert(user): Save the newly created entity using the upsert method provided by the SDK.
Attempt to access a relationship collection method on that entity: Immediately attempt to access a relationship collection method on the newly created entity, for example, user.staked_balances().

Q: What is the error message that occurs when attempting to access the derived collection?

A: The error message that occurs when attempting to access the derived collection is as follows:

Get property "staked_balances" from Entity "MRUser" failed: Value is required but received null or undefined
Error: Get property "staked_balances" from Entity "MRUser" failed: Value is required but received null or undefined
    at handleError (/tmp/sentio/cache/983799004/sentio/V5KQrOvw/node_modules/@sentio/sdk/src/store/decorators.ts:27:11)
    at D0.idGetter (/tmp/sentio/cache/983799004/sentio/V5KQrOvw/node_modules/@sentio/sdk/src/store/decorators.ts:40:18)
    at D0.get (/tmp/sentio/cache/983799004/sentio/V5KQrOvw/node_modules/@sentio/sdk/src/store/decorators.ts:53:34)
    at D0.staked_balances (/tmp/sentio/cache/983799004/sentio/src/schema/schema.rewards.ts:288:17)
    at getOrCreateUserStakedBalance (/tmp/sentio/cache/983799004/sentio/src/processors/multi-rewards-processor.ts:909:40)

Q: What is the expected behavior when accessing derived collections?

A: After creating and persisting a new entity, accessing its relationship collections (even empty ones) should work correctly. The collection accessor should return an empty array rather than throwing an error.

Q: What is the current workaround for this issue?

A: We've implemented a workaround by directly manipulating the ID arrays instead of using the relationship accessors:

// Original code that triggers the bug
const staked_balances = await user.staked_balances();
staked_balances.push(balance);
user._staked_balances = Promise.resolve(staked_balances);

// Workaround
user.staked_balancesIDs.push(balance.id);
await store.upsert(user);

https://github.com/Canopyxyz/sentio-processors/pull/7

Q: What are the possible causes of this issue?

A: The possible causes of this issue are:

Race condition: A race condition might occur when accessing the derived collection before it is properly initialized.
Initialization issue: The SDK might not be properly initializing the internal promises for the derived collections upon entity creation.

Q: How can this issue be solved?

A: To solve this issue, we need to ensure that the derived collections are properly initialized before accessing them. This can be achieved by implementing a mechanism to wait for the initialization of the derived collections before accessing them.

Q: What is the solution to this issue?

A: The solution to this issue is to modify the SDK to include a mechanism to wait for the initialization of the derived collections. This can be achieved by adding a wait method to the entity that returns a promise that resolves when the derived collections are initialized.

Q: How can the solution be implemented?

A: The solution can be implemented by modifying the SDK to include a wait method that returns a promise that resolves when the derived collections are initialized. This can be achieved by adding the following code to the SDK:

// Modified SDK implementation
class Entity {
  // ...
  async wait() {
    // Wait for the initialization of the derived collections
    await this._derivedCollectionsInitialized;
  }
}

// Modified entity implementation
class MRUser extends Entity {
  // ...
  async staked_balances() {
    // Wait for the initialization of the derived collections
    await this.wait();
    // Return the staked balances
    return this._staked_balances;
  }
}

By implementing this solution, we can ensure that the derived collections are properly initialized before accessing them, and the error occurs when accessing the derived collection is resolved.