Transaction-scoped state differs from both persistent storage and per-frame memory.
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A shared temporary checklist is cleared after the whole transaction finishes.
SEE IT FOR YOURSELF
Pack small values into Solidity storage slotsStep 1 / 4
In this simple default-layout example, two uint128 values come before one uint256. Each slot holds thirty-two bytes.
In this simple default-layout example, two uint128 values come before one uint256. Each slot holds thirty-two bytes.The first sixteen-byte value occupies the low-order half of slot zero. Low-order bytes are shown on the right.The second uint128 fits in the remaining sixteen bytes. Both values now share slot zero.C needs a complete thirty-two-byte slot, so it begins at slot one. Two packed small values plus C use two slots.
Animated local teaching model. No wallet, RPC or live blockchain data. Some labels and hashes are abbreviated for readability.
Identify the lifetime
Transient storage lasts for one transaction and is cleared afterward. It is not a mechanism for saving values for the next transaction.
Separate it from frame memory
It can communicate between relevant frames belonging to the same storage owner within a transaction. Ordinary memory belongs to an execution frame and has different sharing behavior.
Respect call context and rollback
Transient writes follow ownership and rollback rules. A reverted scope rolls back its transient changes, and delegatecall uses the caller’s transient storage context.
Design cleanup for composability
A transaction-scoped lock still needs correct release behavior when later operations in the same transaction should proceed. End-of-transaction clearing does not replace careful control flow.
Inspect the layout
TSTORE: write a transient key
TLOAD: read a transient key
Transaction ends → transient values are discarded.
The local packing tool models elementary persistent layout only; it does not execute transient opcodes.