Incorrect contract behavior

Oct 13, 2025 by thesweetdesigns.com 71 views

Introduction

The TEP-74 implementation uses precomputed constants for storage cell and bits to calculate storage fees in the gas.fc file. However, we believe that some of these values are incorrect. In this article, we will discuss the issue, its impact, and the proposed solution.

The Issue

The incorrect values are stored in the following constants:

;;- `JETTON_WALLET_BITS` [/sandbox_tests/StateInit.spec.ts#L92](L92)
const JETTON_WALLET_BITS  = 1033;

;;- `JETTON_WALLET_CELLS`: [/sandbox_tests/StateInit.spec.ts#L92](L92)
const JETTON_WALLET_CELLS = 3;

These values were calculated using the @ton/core library, which parses the blockchain state for a particular account. However, upon closer inspection, we found that the @ton/core sources load the storage stats differently than the code that parses the given slice.

The Correct Calculation

The correct calculation can be found in the @ton/core sources:

// Source: https://github.com/ton-blockchain/ton/blob/24dc184a2ea67f9c47042b4104bbb4d82289fac1/crypto/block/block.tlb#L222
// storage_used$_ cells:(VarUInteger 7) bits:(VarUInteger 7) 
//  public_cells:(VarUInteger 7) = StorageUsed;

export function loadStorageUsed(cs: Slice): StorageUsed {
    return {
        cells: cs.loadVarUintBig(7),
        bits: cs.loadVarUintBig(7),
        publicCells: cs.loadVarUintBig(7),
    }
}

As we can see, the VarUInteger values are actually of size 7, not 3. This discrepancy leads to incorrect storage constants calculations, which eventually ends with wrong storage fees in the production contract.

Impact

The incorrect storage constants have a significant impact on the production contract. The wrong storage fees can lead to:

Incorrect contract behavior: The contract may behave incorrectly, leading to unexpected outcomes.
Financial losses: The incorrect storage fees can result in financial losses for users and the contract itself.
Reputation damage: The incorrect storage fees can damage the reputation of the contract and its developers.

Conclusion

In conclusion, the incorrect bits and cells storage constants in gas.fc are a critical issue that needs to be addressed. The proposed solution is to update the constants to reflect the correct calculation. We recommend that the developers of the TEP-74 implementation review and update the constants to ensure accurate storage fees.

Recommendations

To resolve this issue, we recommend the following:

Update the constants: Update the JETTON_WALLET_BITS and JETTON_WALLET_CELLS constants to reflect the correct calculation.
Review the code: Review the code that parses the given slice to ensure that it accurately loads the storage stats.
Test the contract: Test the contract thoroughly to ensure that it behaves correctly and accurately calculates storage fees.

Contact Us

If you have any questions or concerns, please do not hesitate to contact us. You can reach us at here.

Related Issues

Q: What is the issue with the storage constants in `gas.fc`?

A: The issue is that the storage constants JETTON_WALLET_BITS and JETTON_WALLET_CELLS are calculated incorrectly. The correct calculation can be found in the @ton/core sources, which load the storage stats differently than the code that parses the given slice.

Q: What is the impact of the incorrect storage constants?

A: The incorrect storage constants can lead to incorrect contract behavior, financial losses, and reputation damage. The wrong storage fees can result in unexpected outcomes, financial losses for users and the contract itself, and damage to the reputation of the contract and its developers.

Q: How can I update the storage constants to reflect the correct calculation?

A: To update the storage constants, you need to update the JETTON_WALLET_BITS and JETTON_WALLET_CELLS constants to reflect the correct calculation. You can find the correct calculation in the @ton/core sources.

Q: What is the correct calculation for the storage constants?

A: The correct calculation for the storage constants can be found in the @ton/core sources. The loadStorageUsed function loads the storage stats as follows:

export function loadStorageUsed(cs: Slice): StorageUsed {
    return {
        cells: cs.loadVarUintBig(7),
        bits: cs.loadVarUintBig(7),
        publicCells: cs.loadVarUintBig(7),
    }
}

Q: How can I ensure that the contract behaves correctly and accurately calculates storage fees?

A: To ensure that the contract behaves correctly and accurately calculates storage fees, you need to review the code that parses the given slice to ensure that it accurately loads the storage stats. You also need to test the contract thoroughly to ensure that it behaves correctly and accurately calculates storage fees.

Q: What are the recommended steps to resolve this issue?

A: The recommended steps to resolve this issue are:

Update the constants to reflect the correct calculation.
Review the code that parses the given slice to ensure that it accurately loads the storage stats.
Test the contract thoroughly to ensure that it behaves correctly and accurately calculates storage fees.

Q: Where can I find more information about this issue?

A: You can find more information about this issue in the following resources:

This issue in stablecoin-contract.
This article about the incorrect bits and cells storage constants in gas.fc.
This FAQ about the issue.

Q: How can I contact the developers of the TEP-74 implementation?

A: You can contact the developers of the TEP-74 implementation at here.