ethereum.forks.prague.state
State.
.. contents:: Table of Contents :backlinks: none :local:
Introduction
The state contains all information that is preserved between transactions.
It consists of a main account trie and storage tries for each contract.
There is a distinction between an account that does not exist and
EMPTY_ACCOUNT.
State ¶
Contains all information that is preserved between transactions.
| 30 | @dataclass |
|---|
class State:
_main_trie¶
| 36 | _main_trie: Trie[Address, Optional[Account]] = field( |
|---|---|
| 37 | default_factory=lambda: Trie(secured=True, default=None) |
| 38 | ) |
_storage_tries¶
| 39 | _storage_tries: Dict[Address, Trie[Bytes32, U256]] = field( |
|---|---|
| 40 | default_factory=dict |
| 41 | ) |
_snapshots¶
| 42 | _snapshots: List[ |
|---|---|
| 43 | Tuple[ |
| 44 | Trie[Address, Optional[Account]], |
| 45 | Dict[Address, Trie[Bytes32, U256]], |
| 46 | ] |
| 47 | ] = field(default_factory=list) |
created_accounts¶
| 48 | created_accounts: Set[Address] = field(default_factory=set) |
|---|
TransientStorage ¶
Contains all information that is preserved between message calls within a transaction.
| 51 | @dataclass |
|---|
class TransientStorage:
_tries¶
| 58 | _tries: Dict[Address, Trie[Bytes32, U256]] = field(default_factory=dict) |
|---|
_snapshots¶
| 59 | _snapshots: List[Dict[Address, Trie[Bytes32, U256]]] = field( |
|---|---|
| 60 | default_factory=list |
| 61 | ) |
close_state ¶
Free resources held by the state. Used by optimized implementations to release file descriptors.
begin_transaction ¶
Start a state transaction.
Transactions are entirely implicit and can be nested. It is not possible to calculate the state root during a transaction.
Parameters
state : State The state. transient_storage : TransientStorage The transient storage of the transaction.
def begin_transaction(state: State, transient_storage: TransientStorage) -> None:
| 78 | """ |
|---|---|
| 79 | Start a state transaction. |
| 80 | |
| 81 | Transactions are entirely implicit and can be nested. It is not possible to |
| 82 | calculate the state root during a transaction. |
| 83 | |
| 84 | Parameters |
| 85 | ---------- |
| 86 | state : State |
| 87 | The state. |
| 88 | transient_storage : TransientStorage |
| 89 | The transient storage of the transaction. |
| 90 | |
| 91 | """ |
| 92 | state._snapshots.append( |
| 93 | ( |
| 94 | copy_trie(state._main_trie), |
| 95 | {k: copy_trie(t) for (k, t) in state._storage_tries.items()}, |
| 96 | ) |
| 97 | ) |
| 98 | transient_storage._snapshots.append( |
| 99 | {k: copy_trie(t) for (k, t) in transient_storage._tries.items()} |
| 100 | ) |
commit_transaction ¶
Commit a state transaction.
Parameters
state : State The state. transient_storage : TransientStorage The transient storage of the transaction.
def commit_transaction(state: State, transient_storage: TransientStorage) -> None:
| 106 | """ |
|---|---|
| 107 | Commit a state transaction. |
| 108 | |
| 109 | Parameters |
| 110 | ---------- |
| 111 | state : State |
| 112 | The state. |
| 113 | transient_storage : TransientStorage |
| 114 | The transient storage of the transaction. |
| 115 | |
| 116 | """ |
| 117 | state._snapshots.pop() |
| 118 | if not state._snapshots: |
| 119 | state.created_accounts.clear() |
| 120 | |
| 121 | transient_storage._snapshots.pop() |
rollback_transaction ¶
Rollback a state transaction, resetting the state to the point when the
corresponding begin_transaction() call was made.
Parameters
state : State The state. transient_storage : TransientStorage The transient storage of the transaction.
def rollback_transaction(state: State, transient_storage: TransientStorage) -> None:
| 127 | """ |
|---|---|
| 128 | Rollback a state transaction, resetting the state to the point when the |
| 129 | corresponding `begin_transaction()` call was made. |
| 130 | |
| 131 | Parameters |
| 132 | ---------- |
| 133 | state : State |
| 134 | The state. |
| 135 | transient_storage : TransientStorage |
| 136 | The transient storage of the transaction. |
| 137 | |
| 138 | """ |
| 139 | state._main_trie, state._storage_tries = state._snapshots.pop() |
| 140 | if not state._snapshots: |
| 141 | state.created_accounts.clear() |
| 142 | |
| 143 | transient_storage._tries = transient_storage._snapshots.pop() |
get_account ¶
Get the Account object at an address. Returns EMPTY_ACCOUNT if there
is no account at the address.
Use get_account_optional() if you care about the difference between a
non-existent account and EMPTY_ACCOUNT.
Parameters
state: State
The state
address : Address
Address to lookup.
Returns
account : Account
Account at address.
def get_account(state: State, address: Address) -> Account:
| 147 | """ |
|---|---|
| 148 | Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there |
| 149 | is no account at the address. |
| 150 | |
| 151 | Use `get_account_optional()` if you care about the difference between a |
| 152 | non-existent account and `EMPTY_ACCOUNT`. |
| 153 | |
| 154 | Parameters |
| 155 | ---------- |
| 156 | state: `State` |
| 157 | The state |
| 158 | address : `Address` |
| 159 | Address to lookup. |
| 160 | |
| 161 | Returns |
| 162 | ------- |
| 163 | account : `Account` |
| 164 | Account at address. |
| 165 | |
| 166 | """ |
| 167 | account = get_account_optional(state, address) |
| 168 | if isinstance(account, Account): |
| 169 | return account |
| 170 | else: |
| 171 | return EMPTY_ACCOUNT |
get_account_optional ¶
Get the Account object at an address. Returns None (rather than
EMPTY_ACCOUNT) if there is no account at the address.
Parameters
state: State
The state
address : Address
Address to lookup.
Returns
account : Account
Account at address.
def get_account_optional(state: State, address: Address) -> Optional[Account]:
| 175 | """ |
|---|---|
| 176 | Get the `Account` object at an address. Returns `None` (rather than |
| 177 | `EMPTY_ACCOUNT`) if there is no account at the address. |
| 178 | |
| 179 | Parameters |
| 180 | ---------- |
| 181 | state: `State` |
| 182 | The state |
| 183 | address : `Address` |
| 184 | Address to lookup. |
| 185 | |
| 186 | Returns |
| 187 | ------- |
| 188 | account : `Account` |
| 189 | Account at address. |
| 190 | |
| 191 | """ |
| 192 | account = trie_get(state._main_trie, address) |
| 193 | return account |
set_account ¶
Set the Account object at an address. Setting to None deletes
the account (but not its storage, see destroy_account()).
Parameters
state: State
The state
address : Address
Address to set.
account : Account
Account to set at address.
def set_account(state: State, address: Address, account: Optional[Account]) -> None:
| 199 | """ |
|---|---|
| 200 | Set the `Account` object at an address. Setting to `None` deletes |
| 201 | the account (but not its storage, see `destroy_account()`). |
| 202 | |
| 203 | Parameters |
| 204 | ---------- |
| 205 | state: `State` |
| 206 | The state |
| 207 | address : `Address` |
| 208 | Address to set. |
| 209 | account : `Account` |
| 210 | Account to set at address. |
| 211 | |
| 212 | """ |
| 213 | trie_set(state._main_trie, address, account) |
destroy_account ¶
Completely remove the account at address and all of its storage.
This function is made available exclusively for the SELFDESTRUCT
opcode. It is expected that SELFDESTRUCT will be disabled in a future
hardfork and this function will be removed.
Parameters
state: State
The state
address : Address
Address of account to destroy.
def destroy_account(state: State, address: Address) -> None:
| 217 | """ |
|---|---|
| 218 | Completely remove the account at `address` and all of its storage. |
| 219 | |
| 220 | This function is made available exclusively for the `SELFDESTRUCT` |
| 221 | opcode. It is expected that `SELFDESTRUCT` will be disabled in a future |
| 222 | hardfork and this function will be removed. |
| 223 | |
| 224 | Parameters |
| 225 | ---------- |
| 226 | state: `State` |
| 227 | The state |
| 228 | address : `Address` |
| 229 | Address of account to destroy. |
| 230 | |
| 231 | """ |
| 232 | destroy_storage(state, address) |
| 233 | set_account(state, address, None) |
destroy_storage ¶
Completely remove the storage at address.
Parameters
state: State
The state
address : Address
Address of account whose storage is to be deleted.
def destroy_storage(state: State, address: Address) -> None:
| 237 | """ |
|---|---|
| 238 | Completely remove the storage at `address`. |
| 239 | |
| 240 | Parameters |
| 241 | ---------- |
| 242 | state: `State` |
| 243 | The state |
| 244 | address : `Address` |
| 245 | Address of account whose storage is to be deleted. |
| 246 | |
| 247 | """ |
| 248 | if address in state._storage_tries: |
| 249 | del state._storage_tries[address] |
mark_account_created ¶
Mark an account as having been created in the current transaction.
This information is used by get_storage_original() to handle an obscure
edgecase, and to respect the constraints added to SELFDESTRUCT by
EIP-6780.
The marker is not removed even if the account creation reverts. Since the
account cannot have had code prior to its creation and can't call
get_storage_original(), this is harmless.
Parameters
state: State
The state
address : Address
Address of the account that has been created.
def mark_account_created(state: State, address: Address) -> None:
| 253 | """ |
|---|---|
| 254 | Mark an account as having been created in the current transaction. |
| 255 | This information is used by `get_storage_original()` to handle an obscure |
| 256 | edgecase, and to respect the constraints added to SELFDESTRUCT by |
| 257 | EIP-6780. |
| 258 | |
| 259 | The marker is not removed even if the account creation reverts. Since the |
| 260 | account cannot have had code prior to its creation and can't call |
| 261 | `get_storage_original()`, this is harmless. |
| 262 | |
| 263 | Parameters |
| 264 | ---------- |
| 265 | state: `State` |
| 266 | The state |
| 267 | address : `Address` |
| 268 | Address of the account that has been created. |
| 269 | |
| 270 | """ |
| 271 | state.created_accounts.add(address) |
get_storage ¶
Get a value at a storage key on an account. Returns U256(0) if the
storage key has not been set previously.
Parameters
state: State
The state
address : Address
Address of the account.
key : Bytes
Key to lookup.
Returns
value : U256
Value at the key.
def get_storage(state: State, address: Address, key: Bytes32) -> U256:
| 275 | """ |
|---|---|
| 276 | Get a value at a storage key on an account. Returns `U256(0)` if the |
| 277 | storage key has not been set previously. |
| 278 | |
| 279 | Parameters |
| 280 | ---------- |
| 281 | state: `State` |
| 282 | The state |
| 283 | address : `Address` |
| 284 | Address of the account. |
| 285 | key : `Bytes` |
| 286 | Key to lookup. |
| 287 | |
| 288 | Returns |
| 289 | ------- |
| 290 | value : `U256` |
| 291 | Value at the key. |
| 292 | |
| 293 | """ |
| 294 | trie = state._storage_tries.get(address) |
| 295 | if trie is None: |
| 296 | return U256(0) |
| 297 | |
| 298 | value = trie_get(trie, key) |
| 299 | |
| 300 | assert isinstance(value, U256) |
| 301 | return value |
set_storage ¶
Set a value at a storage key on an account. Setting to U256(0) deletes
the key.
Parameters
state: State
The state
address : Address
Address of the account.
key : Bytes
Key to set.
value : U256
Value to set at the key.
def set_storage(state: State, address: Address, key: Bytes32, value: U256) -> None:
| 307 | """ |
|---|---|
| 308 | Set a value at a storage key on an account. Setting to `U256(0)` deletes |
| 309 | the key. |
| 310 | |
| 311 | Parameters |
| 312 | ---------- |
| 313 | state: `State` |
| 314 | The state |
| 315 | address : `Address` |
| 316 | Address of the account. |
| 317 | key : `Bytes` |
| 318 | Key to set. |
| 319 | value : `U256` |
| 320 | Value to set at the key. |
| 321 | |
| 322 | """ |
| 323 | assert trie_get(state._main_trie, address) is not None |
| 324 | |
| 325 | trie = state._storage_tries.get(address) |
| 326 | if trie is None: |
| 327 | trie = Trie(secured=True, default=U256(0)) |
| 328 | state._storage_tries[address] = trie |
| 329 | trie_set(trie, key, value) |
| 330 | if trie._data == {}: |
| 331 | del state._storage_tries[address] |
storage_root ¶
Calculate the storage root of an account.
Parameters
state: The state address : Address of the account.
Returns
root : Root
Storage root of the account.
def storage_root(state: State, address: Address) -> Root:
| 335 | """ |
|---|---|
| 336 | Calculate the storage root of an account. |
| 337 | |
| 338 | Parameters |
| 339 | ---------- |
| 340 | state: |
| 341 | The state |
| 342 | address : |
| 343 | Address of the account. |
| 344 | |
| 345 | Returns |
| 346 | ------- |
| 347 | root : `Root` |
| 348 | Storage root of the account. |
| 349 | |
| 350 | """ |
| 351 | assert not state._snapshots |
| 352 | if address in state._storage_tries: |
| 353 | return root(state._storage_tries[address]) |
| 354 | else: |
| 355 | return EMPTY_TRIE_ROOT |
state_root ¶
Calculate the state root.
Parameters
state: The current state.
Returns
root : Root
The state root.
def state_root(state: State) -> Root:
| 359 | """ |
|---|---|
| 360 | Calculate the state root. |
| 361 | |
| 362 | Parameters |
| 363 | ---------- |
| 364 | state: |
| 365 | The current state. |
| 366 | |
| 367 | Returns |
| 368 | ------- |
| 369 | root : `Root` |
| 370 | The state root. |
| 371 | |
| 372 | """ |
| 373 | assert not state._snapshots |
| 374 | |
| 375 | def get_storage_root(address: Address) -> Root: |
| 376 | return storage_root(state, address) |
| 377 | |
| 378 | return root(state._main_trie, get_storage_root=get_storage_root) |
account_exists ¶
Checks if an account exists in the state trie.
Parameters
state: The state address: Address of the account that needs to be checked.
Returns
account_exists : bool
True if account exists in the state trie, False otherwise
def account_exists(state: State, address: Address) -> bool:
| 382 | """ |
|---|---|
| 383 | Checks if an account exists in the state trie. |
| 384 | |
| 385 | Parameters |
| 386 | ---------- |
| 387 | state: |
| 388 | The state |
| 389 | address: |
| 390 | Address of the account that needs to be checked. |
| 391 | |
| 392 | Returns |
| 393 | ------- |
| 394 | account_exists : `bool` |
| 395 | True if account exists in the state trie, False otherwise |
| 396 | |
| 397 | """ |
| 398 | return get_account_optional(state, address) is not None |
account_has_code_or_nonce ¶
Checks if an account has non-zero nonce or non-empty code.
Parameters
state: The state address: Address of the account that needs to be checked.
Returns
has_code_or_nonce : bool
True if the account has non-zero nonce or non-empty code,
False otherwise.
def account_has_code_or_nonce(state: State, address: Address) -> bool:
| 402 | """ |
|---|---|
| 403 | Checks if an account has non-zero nonce or non-empty code. |
| 404 | |
| 405 | Parameters |
| 406 | ---------- |
| 407 | state: |
| 408 | The state |
| 409 | address: |
| 410 | Address of the account that needs to be checked. |
| 411 | |
| 412 | Returns |
| 413 | ------- |
| 414 | has_code_or_nonce : `bool` |
| 415 | True if the account has non-zero nonce or non-empty code, |
| 416 | False otherwise. |
| 417 | |
| 418 | """ |
| 419 | account = get_account(state, address) |
| 420 | return account.nonce != Uint(0) or account.code != b"" |
account_has_storage ¶
Checks if an account has storage.
Parameters
state: The state address: Address of the account that needs to be checked.
Returns
has_storage : bool
True if the account has storage, False otherwise.
def account_has_storage(state: State, address: Address) -> bool:
| 424 | """ |
|---|---|
| 425 | Checks if an account has storage. |
| 426 | |
| 427 | Parameters |
| 428 | ---------- |
| 429 | state: |
| 430 | The state |
| 431 | address: |
| 432 | Address of the account that needs to be checked. |
| 433 | |
| 434 | Returns |
| 435 | ------- |
| 436 | has_storage : `bool` |
| 437 | True if the account has storage, False otherwise. |
| 438 | |
| 439 | """ |
| 440 | return address in state._storage_tries |
is_account_alive ¶
Check whether an account is both in the state and non-empty.
Parameters
state: The state address: Address of the account that needs to be checked.
Returns
is_alive : bool
True if the account is alive.
def is_account_alive(state: State, address: Address) -> bool:
| 444 | """ |
|---|---|
| 445 | Check whether an account is both in the state and non-empty. |
| 446 | |
| 447 | Parameters |
| 448 | ---------- |
| 449 | state: |
| 450 | The state |
| 451 | address: |
| 452 | Address of the account that needs to be checked. |
| 453 | |
| 454 | Returns |
| 455 | ------- |
| 456 | is_alive : `bool` |
| 457 | True if the account is alive. |
| 458 | |
| 459 | """ |
| 460 | account = get_account_optional(state, address) |
| 461 | return account is not None and account != EMPTY_ACCOUNT |
modify_state ¶
Modify an Account in the State. If, after modification, the account
exists and has zero nonce, empty code, and zero balance, it is destroyed.
def modify_state(state: State, address: Address, f: Callable[[Account], None]) -> None:
| 467 | """ |
|---|---|
| 468 | Modify an `Account` in the `State`. If, after modification, the account |
| 469 | exists and has zero nonce, empty code, and zero balance, it is destroyed. |
| 470 | """ |
| 471 | set_account(state, address, modify(get_account(state, address), f)) |
| 472 | |
| 473 | account = get_account_optional(state, address) |
| 474 | account_exists_and_is_empty = ( |
| 475 | account is not None |
| 476 | and account.nonce == Uint(0) |
| 477 | and account.code == b"" |
| 478 | and account.balance == 0 |
| 479 | ) |
| 480 | |
| 481 | if account_exists_and_is_empty: |
| 482 | destroy_account(state, address) |
move_ether ¶
Move funds between accounts.
def move_ether(state: State, sender_address: Address, recipient_address: Address, amount: U256) -> None:
| 491 | """ |
|---|---|
| 492 | Move funds between accounts. |
| 493 | """ |
| 494 | |
| 495 | def reduce_sender_balance(sender: Account) -> None: |
| 496 | if sender.balance < amount: |
| 497 | raise AssertionError |
| 498 | sender.balance -= amount |
| 499 | |
| 500 | def increase_recipient_balance(recipient: Account) -> None: |
| 501 | recipient.balance += amount |
| 502 | |
| 503 | modify_state(state, sender_address, reduce_sender_balance) |
| 504 | modify_state(state, recipient_address, increase_recipient_balance) |
set_account_balance ¶
Sets the balance of an account.
Parameters
state: The current state.
address: Address of the account whose nonce needs to be incremented.
amount: The amount that needs to be set in the balance.
def set_account_balance(state: State, address: Address, amount: U256) -> None:
| 508 | """ |
|---|---|
| 509 | Sets the balance of an account. |
| 510 | |
| 511 | Parameters |
| 512 | ---------- |
| 513 | state: |
| 514 | The current state. |
| 515 | |
| 516 | address: |
| 517 | Address of the account whose nonce needs to be incremented. |
| 518 | |
| 519 | amount: |
| 520 | The amount that needs to be set in the balance. |
| 521 | |
| 522 | """ |
| 523 | |
| 524 | def set_balance(account: Account) -> None: |
| 525 | account.balance = amount |
| 526 | |
| 527 | modify_state(state, address, set_balance) |
increment_nonce ¶
Increments the nonce of an account.
Parameters
state: The current state.
address: Address of the account whose nonce needs to be incremented.
def increment_nonce(state: State, address: Address) -> None:
| 531 | """ |
|---|---|
| 532 | Increments the nonce of an account. |
| 533 | |
| 534 | Parameters |
| 535 | ---------- |
| 536 | state: |
| 537 | The current state. |
| 538 | |
| 539 | address: |
| 540 | Address of the account whose nonce needs to be incremented. |
| 541 | |
| 542 | """ |
| 543 | |
| 544 | def increase_nonce(sender: Account) -> None: |
| 545 | sender.nonce += Uint(1) |
| 546 | |
| 547 | modify_state(state, address, increase_nonce) |
set_code ¶
Sets Account code.
Parameters
state: The current state.
address: Address of the account whose code needs to be updated.
code: The bytecode that needs to be set.
def set_code(state: State, address: Address, code: Bytes) -> None:
| 551 | """ |
|---|---|
| 552 | Sets Account code. |
| 553 | |
| 554 | Parameters |
| 555 | ---------- |
| 556 | state: |
| 557 | The current state. |
| 558 | |
| 559 | address: |
| 560 | Address of the account whose code needs to be updated. |
| 561 | |
| 562 | code: |
| 563 | The bytecode that needs to be set. |
| 564 | |
| 565 | """ |
| 566 | |
| 567 | def write_code(sender: Account) -> None: |
| 568 | sender.code = code |
| 569 | |
| 570 | modify_state(state, address, write_code) |
get_storage_original ¶
Get the original value in a storage slot i.e. the value before the current transaction began. This function reads the value from the snapshots taken before executing the transaction.
Parameters
state: The current state. address: Address of the account to read the value from. key: Key of the storage slot.
def get_storage_original(state: State, address: Address, key: Bytes32) -> U256:
| 574 | """ |
|---|---|
| 575 | Get the original value in a storage slot i.e. the value before the current |
| 576 | transaction began. This function reads the value from the snapshots taken |
| 577 | before executing the transaction. |
| 578 | |
| 579 | Parameters |
| 580 | ---------- |
| 581 | state: |
| 582 | The current state. |
| 583 | address: |
| 584 | Address of the account to read the value from. |
| 585 | key: |
| 586 | Key of the storage slot. |
| 587 | |
| 588 | """ |
| 589 | # In the transaction where an account is created, its preexisting storage |
| 590 | # is ignored. |
| 591 | if address in state.created_accounts: |
| 592 | return U256(0) |
| 593 | |
| 594 | _, original_trie = state._snapshots[0] |
| 595 | original_account_trie = original_trie.get(address) |
| 596 | |
| 597 | if original_account_trie is None: |
| 598 | original_value = U256(0) |
| 599 | else: |
| 600 | original_value = trie_get(original_account_trie, key) |
| 601 | |
| 602 | assert isinstance(original_value, U256) |
| 603 | |
| 604 | return original_value |
get_transient_storage ¶
Get a value at a storage key on an account from transient storage.
Returns U256(0) if the storage key has not been set previously.
Parameters
transient_storage: TransientStorage
The transient storage
address : Address
Address of the account.
key : Bytes
Key to lookup.
Returns
value : U256
Value at the key.
def get_transient_storage(transient_storage: TransientStorage, address: Address, key: Bytes32) -> U256:
| 610 | """ |
|---|---|
| 611 | Get a value at a storage key on an account from transient storage. |
| 612 | Returns `U256(0)` if the storage key has not been set previously. |
| 613 | |
| 614 | Parameters |
| 615 | ---------- |
| 616 | transient_storage: `TransientStorage` |
| 617 | The transient storage |
| 618 | address : `Address` |
| 619 | Address of the account. |
| 620 | key : `Bytes` |
| 621 | Key to lookup. |
| 622 | |
| 623 | Returns |
| 624 | ------- |
| 625 | value : `U256` |
| 626 | Value at the key. |
| 627 | |
| 628 | """ |
| 629 | trie = transient_storage._tries.get(address) |
| 630 | if trie is None: |
| 631 | return U256(0) |
| 632 | |
| 633 | value = trie_get(trie, key) |
| 634 | |
| 635 | assert isinstance(value, U256) |
| 636 | return value |
set_transient_storage ¶
Set a value at a storage key on an account. Setting to U256(0) deletes
the key.
Parameters
transient_storage: TransientStorage
The transient storage
address : Address
Address of the account.
key : Bytes
Key to set.
value : U256
Value to set at the key.
def set_transient_storage(transient_storage: TransientStorage, address: Address, key: Bytes32, value: U256) -> None:
| 645 | """ |
|---|---|
| 646 | Set a value at a storage key on an account. Setting to `U256(0)` deletes |
| 647 | the key. |
| 648 | |
| 649 | Parameters |
| 650 | ---------- |
| 651 | transient_storage: `TransientStorage` |
| 652 | The transient storage |
| 653 | address : `Address` |
| 654 | Address of the account. |
| 655 | key : `Bytes` |
| 656 | Key to set. |
| 657 | value : `U256` |
| 658 | Value to set at the key. |
| 659 | |
| 660 | """ |
| 661 | trie = transient_storage._tries.get(address) |
| 662 | if trie is None: |
| 663 | trie = Trie(secured=True, default=U256(0)) |
| 664 | transient_storage._tries[address] = trie |
| 665 | trie_set(trie, key, value) |
| 666 | if trie._data == {}: |
| 667 | del transient_storage._tries[address] |