Ethereum: Why is my contribution method not working due to missing recovery data

As a developer working on a Solidity smart contract for an initial coin offering (ICO), you may have encountered several issues that could hinder the success of your project. One common error that occurs during testing is the “missing recovery data” issue, which affects the operation of certain contribution methods. In this article, we will look at what causes this error and provide instructions on how to fix the issue in your contract.

What does “missing recovery data” mean?

A “reset” event occurs in Ethereum when an invalid or unsupported state is encountered during a transaction. This can happen for a variety of reasons, including:

• Invalid or missing contract data: If the internal variables of the contract are not initialized correctly, this can cause a cancellation.

• Invalid function calls: Functions that do not follow standard Solidity syntax or use incorrect parameter types can cause cancellations.

• Uninitialized state variables: Failure to set the contract state properly before using certain functions can cause cancellations.

Why doesn’t my consent method work if recovery data is missing?

Let’s say your contribution method looks like this:

pragma strength ^0.6.0;
contract TokenContributor {
public owner address;
uint state balance = 0;
// Token contribution function
function contribute() public payable {
request(msg.value >= 1 ether, "Invalid input");
if (balance > 0) {
request(msg.value == balance * 1 ether, "Token must be equal to initial amount");
balance += msg.value;
} else {
// Add a reset condition
}
}
}

In this example, the “invest” function checks whether the user has submitted enough tokens and whether their investment matches the initial value. However, there is no “return” statement to handle cases where an invalid or missing state variable is encountered.

“Missing recovery data” error

If the contract encounters a reset event, it stops execution and returns control to the caller with an error message indicating that the input is invalid or the state has changed. This can cause the investment method to fail if not handled properly.

For example, let’s say you try to donate 100 tokens, but get a refund:

pragma strength ^0.6.0;
contract TokenContributor {
address public owner;
uint state balance = 0;
// Token contribution function
function contribute() public payable {
request(msg.value >= 1 ether, "Invalid input");
if (balance > 0) {
request(msg.value == balance * 100 ether, "Token must be equal to original amount");
balance += msg.value;
} else {
// Reset condition here
return();
}
}
}

In this case, when a user tries to add 100 tokens but receives an invalid reset message, their consent method will fail and execution will be aborted.

Resolving the Missing Refresh Data Issue

To fix this issue, you need to add “reset” statements to your contract functions that can cause a reset. Here are some suggestions:

• Add a reset condition to the beginning of each function: This ensures that an error message is displayed if invalid or missing state variables are encountered.

“` strength

pragma strength ^0.6.0;

contract TokenContributor {

public owner address;

uint state balance = 0;

// Token contribution function

function contribute() public payable {

request(msg.value >= 1 ether, “Invalid input”);

if (balance > 0) {

request(msg.value == balance * 100 ether, “Token must be equal to original amount”);

balance += message