Understanding the “Custom Program Error” in Solana
As a new developer working in Anchor, a popular Rust framework for building blockchain applications in the Solana framework, you may have encountered an error that is hard to explain. The error message you see is called a “custom program error” (0x7d6) and indicates that there is a problem processing transactions in the Solana network.
What is a custom program error?
In the context of Anchor, a custom program error occurs when the Anchor runtime encounters a piece of code in a Rust program that does not follow the rules of the Solana programming language. This may seem like a minor bug, but it can actually prevent your application from working properly.
“Failed to send transaction” error
In this case, you are getting the error: “Transaction simulation failed: An error occurred while processing instruction 0.” This means that there is a problem with the program instructions (i.e. the code that is executed during transaction simulation). The specific statement that caused this error is marked as Statement 0.
“Error processing custom program” message
When you run a Rust program, Anchor tries to execute it in a test environment. This test environment is necessary because Solana applications must meet strict code compliance rules. If your code does not meet these requirements, Anchor will display an error indicating a problem with the custom program.
Troubleshooting steps
To resolve this issue, follow these steps:
- Review your code: Check for suspicious or incompatible code segments in your Rust program. Make sure that all statements are defined correctly and follow the rules of the Solana programming language.
- Check for typos: Double-check your code for typos in variable names, function definitions, and other areas where Anchor can flag potential problems.
- Check dependencies: Make sure that you are using all required dependencies and libraries in your project to ensure that they are compliant with Solana standards.
What to do if the problem persists?
If you still get the same error after reviewing and updating your code, try:
- Using a different version of Anchor or Rust: Sometimes, problems are specific to specific versions or configurations. Try switching to an older or newer version and see if the problem goes away.
- Running with the
--debugflag: This flag allows Anchor to print out more detailed information about the build process, which can help identify the root cause of the problem.
Conclusion
To understand and resolve non-standard program errors in Solana, it is important to pay attention to the details and analyze the code carefully. If you follow the steps below and keep the strict rules of the Solana programming language in mind, you should be able to resolve the issue and continue developing your project on the platform.
Example use case
To show how to troubleshoot and fix custom bugs in Rust programs, consider the following example:
«`rust
use anchor_lang::prelude::*;
// Define a simple function that simulates a transaction
pub fn my_function() -> Result<(), Error> {
// Simulate an error: this will print «Error processing custom program»
Error(Error::custom(0x7d6))
}
#[program]
pub mod solana_program {
use anchor_lang::{account_info, entrypoint, storage};
use std::collections::HashMap;
#[call]
pub fn my_function() -> Result
let state = account_info::load_storage(&key_prefix!())?;
// Perform some operation…
OK(())
}
#[entry point]
fn main() -> Result<(), Error> {
// … (other entry points)
if let Err(err) = my_function() {
// Handle error
print!