HIP-1049: Deleted flag in ConsensusGetTopic

Abstract

This HIP proposes to add a deleted flag to the response of a ConsensusGetTopicInfo-query.

Motivation

Knowing if a topic has been deleted is essential for many use cases. Query results for all other entity types contain this information but are missing for topics.

Rationale

Deleted entities are not immediately removed but marked as being deleted. Queries return these entities. The response for other entity types (e.g., Account, Token) contains a deleted flag that is true if the entity has been removed.

The results of ConsensusGetTopicInfo-queries do not contain such a flag. This information is crucial for many use cases. For instance, a deleted topic should not be used anymore.

User stories

As a user, I want to know if a Topic has been deleted.

Specification

The message ConsensusTopicInfo is returned as a response to a ConsensusGetTopicInfo-query. It contains a deleted flag, which is true if the entity has been removed and false otherwise.

message ConsensusTopicInfo {

    [...]
    
    /**
     * Specifies whether the topic was deleted or not
     */
    bool deleted = 10;
}

Backwards Compatibility

The attribute is additional and can safely be ignored by existing code.

Security Implications

The new flag imposes no new security risk.

How to Teach This

Documentation for the ConsensusGetTopicInfo-query has to be updated.

Reference Implementation

The reference implementation must be complete before any HIP is given the status of “Final”. The final implementation must include test code and documentation.

Rejected Ideas

An enum state with the states ACTIVE and DELETED would have been extensible. However, we use a deleted flag already in similar situations and decided to be consistent.

Open Issues

None.

References

N/A

Copyright/license

This document is licensed under the Apache License, Version 2.0 – see LICENSE or (https://www.apache.org/licenses/LICENSE-2.0)

Citation

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