soroban_redundant_storage_read

Default Severity: warn

What it does

Detects when the same storage key is read multiple times in sequence without an intervening write. This catches redundant get and has calls on Instance, Persistent, and Temporary storage.

Why is this bad?

DANGER

Storage reads in Soroban consume read-throughput bandwidth. Reading the same key multiple times without modification wastes this resource and increases transaction fees.

Example

// ❌ Bad: two sequential reads of the same key
let a: Option<i32> = env.storage().instance().get(&key);
let b: Option<i32> = env.storage().instance().get(&key); // redundant!

Suggested Fix

TIP

Store the value from the first read and reuse it instead of reading the same key again.

// ✅ Good: read once, reuse the value
let a: Option<i32> = env.storage().instance().get(&key);
let b: Option<i32> = a; // reuse the first read

Scope

• Fires on sequential get and has calls on Instance, Persistent, and Temporary storage types.
• A set (write) resets the tracking, so reads before and after a write are not flagged.
• Reads of different keys (even on the same storage type) are not flagged.
• Only tracks reads at the top level of statements within the same block. Nested block tracking is not yet supported.