Without the protocol amendment introduced by this commit, an NFT ID can
be reminted in this manner:
1. Alice creates an account and mints an NFT.
2. Alice burns the NFT with an `NFTokenBurn` transaction.
3. Alice deletes her account with an `AccountDelete` transaction.
4. Alice re-creates her account.
5. Alice mints an NFT with an `NFTokenMint` transaction with params:
`NFTokenTaxon` = 0, `Flags` = 9).
This will mint a NFT with the same `NFTokenID` as the one minted in step
1. The params that construct the NFT ID will cause a collision in
`NFTokenID` if their values are equal before and after the remint.
With the `fixNFTokenRemint` amendment, there is a new sequence number
construct which avoids this scenario:
- A new `AccountRoot` field, `FirstNFTSequence`, stays constant over
time.
- This field is set to the current account sequence when the account
issues their first NFT.
- Otherwise, it is not set.
- The sequence of a newly-minted NFT is computed by: `FirstNFTSequence +
MintedNFTokens`.
- `MintedNFTokens` is then incremented by 1 for each mint.
Furthermore, there is a new account deletion restriction:
- An account can only be deleted if `FirstNFTSequence + MintedNFTokens +
256` is less than the current ledger sequence.
- 256 was chosen because it already exists in the current account
deletion constraint.
Without this restriction, an NFT may still be remintable. Example
scenario:
1. Alice's account sequence is at 1.
2. Bob is Alice's authorized minter.
3. Bob mints 500 NFTs for Alice. The NFTs will have sequences 1-501, as
NFT sequence is computed by `FirstNFTokenSequence + MintedNFTokens`).
4. Alice deletes her account at ledger 257 (as required by the existing
`AccountDelete` amendment).
5. Alice re-creates her account at ledger 258.
6. Alice mints an NFT. `FirstNFTokenSequence` initializes to her account
sequence (258), and `MintedNFTokens` initializes as 0. This
newly-minted NFT would have a sequence number of 258, which is a
duplicate of what she issued through authorized minting before she
deleted her account.
---------
Signed-off-by: Shawn Xie <shawnxie920@gmail.com>
* Introduces amendment `XRPFees`
* Convert fee voting and protocol messages to use XRPAmounts
* Includes Validations, Change transactions, the "Fees" ledger object,
and subscription messages
* Improve handling of 0 drop reference fee with TxQ. For use with networks that do not want to require fees
* Note that fee escalation logic is still in place, which may cause the
open ledger fee to rise if the network is busy. 0 drop transactions
will still queue, and fee escalation can be effectively disabled by
modifying the configuration on all nodes
* Change default network reserves to match Mainnet
* Name the new SFields *Drops (not *XRP)
* Reserve SField IDs for Hooks
* Clarify comments explaining the ttFEE transaction field validation
Tickets are a mechanism to allow for the "out-of-order" execution of
transactions on the XRP Ledger.
This commit, if merged, reworks the existing support for tickets and
introduces support for 'ticket batching', completing the feature set
needed for tickets.
The code is gated under the newly-introduced `TicketBatch` amendment
and the `Tickets` amendment, which is not presently active on the
network, is being removed.
The specification for this change can be found at:
https://github.com/xrp-community/standards-drafts/issues/16
This change can help improve the liveness of the network during periods of network
instability, by allowing the network to track which validators are presently not online
and to disregard them for the purposes of quorum calculations.
At this point all of the jss::* names are defined in the same
file. That file has been named JsonFields.h. That file name
has little to do with either JsonStaticStrings (which is what
jss is short for) or with jss. The file is renamed to jss.h
so the file name better reflects what the file contains.
All includes of that file are fixed. A few include order
issues are tidied up along the way.
Formerly an SOTemplate was default constructed and its elements
added using push_back(). This left open the possibility of a
malformed SOTemplate if adding one of the elements caused a throw.
With this commit the SOTemplate requires an initializer_list of
its elements at construction. Elements may not be added after
construction. With this approach either the SOTemplate is fully
constructed with all of its elements or the constructor throws,
which prevents an invalid SOTemplate from even existing.
This change requires all SOTemplate construction to be adjusted
at the call site. Those changes are also in this commit.
The SOE_Flags enum is also renamed to SOEStyle, which harmonizes
the name with other uses in the code base. SOEStyle elements
are renamed (slightly) to have an "soe" prefix rather than "SOE_".
This heads toward reserving identifiers with all upper case for
macros. The new style also aligns with other prominent enums in
the code base like the collection of TER identifiers.
SOElement is adjusted so it can be stored directly in an STL
container, rather than requiring storage in a unique_ptr.
Correspondingly, unique_ptr usage is removed from both
SOTemplate and KnownFormats.
The lsfDepositAuth flag limits the AccountIDs that can deposit into
the account that has the flag set. The original design only
allowed deposits to complete if the account with the flag set also
signed the transaction that caused the deposit.
The DepositPreauth ledger type allows an account with the
lsfDepositAuth flag set to preauthorize additional accounts.
This preauthorization allows them to sign deposits as well. An
account can add DepositPreauth objects to the ledger (and remove
them as well) using the DepositPreauth transaction.
Introduce a new ledger type: ltCHECK
Introduce three new transactions that operate on checks:
- "CheckCreate" which adds the check entry to the ledger. The
check is a promise from the source of the check that the
destination of the check may cash the check and receive up to
the SendMax specified on the check. The check may have an
expiration, after which the check may no longer be cashed.
- "CheckCash" is a request by the destination of the check to
transfer a requested amount of funds, up to the check's SendMax,
from the source to the destination. The destination may receive
less than the SendMax due to transfer fees.
When cashing a check, the destination specifies the smallest
amount of funds that will be acceptable. If the transfer
completes and delivers the requested amount, then the check is
considered cashed and removed from the ledger. If enough funds
cannot be delivered, then the transaction fails and the check
remains in the ledger.
Attempting to cash the check after its expiration will fail.
- "CheckCancel" removes the check from the ledger without
transferring funds. Either the check's source or destination
can cancel the check at any time. After a check has expired,
any account can cancel the check.
Facilities related to checks are on the "Checks" amendment.
Introduce "fix1523" which corrects a minor technical flaw with
the original implementation of the escrow feature.
When creating an escrow, the entry would only be tracked in the
owner directory of the sender; as a result, an escrow recipient
would not be able to detect incoming escrows without monitoring
the ledger in real-time for transactions of interest or without
the sender communicating this information out of band.
With the fix in place, escrows where the recipient differs from
the sender will be listed in the recipient's owner directory as
well.
The 'type' field allows the rpc client to specify what type of ledger
entries to retrieve. The available types are:
"account"
"amendments"
"directory"
"fee"
"hashes"
"offer"
"signer_list"
"state"
"ticket"
Escrow replaces the existing SusPay implementation with improved
code that also adds hashlock support to escrow payments, making
RCL ILP enabled.
The new functionality is under the `Escrow` amendment, which
supersedes and replaces the `SusPay` amendment.
This commit also deprecates the `CryptoConditions` amendment
which is replaced by the `CryptoConditionSuite` amendment which,
once enabled, will allow use of cryptoconditions others than
hashlocks.
Add an amendment to allow gateways to set a "tick size"
for assets they issue. There are no changes unless the
amendment is enabled (since the tick size option cannot
be set).
With the amendment enabled:
AccountSet transactions may set a "TickSize" parameter.
Legal values are 0 and 3-15 inclusive. Zero removes the
setting. 3-15 allow that many decimal digits of precision
in the pricing of offers for assets issued by this account.
For asset pairs with XRP, the tick size imposed, if any,
is the tick size of the issuer of the non-XRP asset. For
asset pairs without XRP, the tick size imposed, if any,
is the smaller of the two issuer's configured tick sizes.
The tick size is imposed by rounding the offer quality
down to nearest tick and recomputing the non-critical
side of the offer. For a buy, the amount offered is
rounded down. For a sell, the amount charged is rounded up.
Gateways must enable a TickSize on their account for this
feature to benefit them.
The primary expected benefit is the elimination of bots
fighting over the tip of the order book. This means:
- Quicker price discovery as outpricing someone by a
microscopic amount is made impossible. Currently
bots can spend hours outbidding each other with no
significant price movement.
- A reduction in offer creation and cancellation spam.
- More offers left on the books as priority means
something when you can't outbid by a microscopic amount.
A conditional suspended payment is a suspended payment where
completion of the payment is contingent upon the fulfillment
of a condition defined by the sender during creation of the
suspended payment.
This commit also introduces the "CryptoConditions" amendment
which controls whether cryptoconditions will be supported
in suspended payments. The existing "SusPay" amendment can
be used to enable suspended payments without enabling the
cryptoconditions code.
Payment channels permit off-ledger checkpoints of XRP payments flowing
in a single direction. A channel sequesters the owner's XRP in its own
ledger entry. The owner can authorize the recipient to claim up to a
give balance by giving the receiver a signed message (off-ledger). The
recipient can use this signed message to claim any unpaid balance while
the channel remains open. The owner can top off the line as needed. If
the channel has not paid out all its funds, the owner must wait out a
delay to close the channel to give the recipient a chance to supply any
claims. The recipient can close the channel at any time. Any transaction
that touches the channel after the expiration time will close the
channel. The total amount paid increases monotonically as newer claims
are issued. When the channel is closed any remaining balance is returned
to the owner. Channels are intended to permit intermittent off-ledger
settlement of ILP trust lines as balances get substantial. For
bidirectional channels, a payment channel can be used in each direction.
