Program Errors and Logs

Surface failures and logs from on-chain programs. Results appear in the same fence: same-line // comments when short, multiline // blocks below the sample when not.

msg Macro

Print to program logs (expensive - keep sparse).

// msg!("amount={}", amount);

ProgramError

Built-in program error codes.

// return Err(ProgramError::InvalidAccountData.into());

require

Anchor require! aborts with error.

// require!(amount > 0, MyError::ZeroAmount);

Anchor error

#[error_code] enum for typed errors.

// #[error_code] pub enum MyError { #[msg("zero")] ZeroAmount }

Logs in Sim

Simulation returns logs array.

// sim.value.logs

Custom ProgramError

Map u32 custom codes in native programs.

// ProgramError::Custom(1)

AccountNotSigner

Common missing signature error.

// ProgramError::MissingRequiredSignature

Constraint Error

Anchor constraint failures include account name.

// Error: ConstraintSeeds / ConstraintHasOne

sol_log_data

Log binary base64 data.

// sol_log_data(&[bytes])

Return Data Error

Prefer typed errors over only logs.

// Err(error!(MyError::X))

Panic Avoid

Panics abort; prefer Result.

// avoid unwrap in on-chain paths

CU Exhausted

Compute budget exceeded fails tx.

// Program failed: Computational budget exceeded

Idempotent Logs

Do not log secrets or full private keys.

// log pubkeys and amounts carefully

has_one Fail

has_one mismatch error.

// ConstraintHasOne

emit Event

Anchor events for indexers.

// emit!(MyEvent { ... })

Related

• Anchor Program Basics - Result returns
• Testing Local Validator - assert logs
• CPI Cross Program - CPI error maps

Stack versions: This page was written for Agave 4.1.1, Solana CLI 3.0.10, Anchor 0.32.1, Rust 1.91.1, and @solana/kit 7.0.0.