Fix interactions between NFTokenOffers and trust lines.
Since the NFTokenAcceptOffer does not check the trust line that
the issuer receives as a transfer fee in the NFTokenAcceptOffer,
if the issuer deletes the trust line after NFTokenCreateOffer,
the trust line is created for the issuer by the
NFTokenAcceptOffer. That's fixed.
Resolves#4925.
Fixes issue #4937.
The fixReducedOffersV1 amendment fixed certain forms of offer
modification that could lead to blocked order books. Reduced
offers can block order books if the effective quality of the
reduced offer is worse than the quality of the original offer
(from the perspective of the taker). It turns out that, for
small values, the quality of the reduced offer can be
significantly affected by the rounding mode used during
scaling computations.
Issue #4937 identified an additional code path that modified
offers in a way that could lead to blocked order books. This
commit changes the rounding in that newly located code path so
the quality of the modified offer is never worse than the
quality of the offer as it was originally placed.
It is possible that additional ways of producing blocking
offers will come to light. Therefore there may be a future
need for a V3 amendment.
* Add trap_tx_hash command line option
This new option can be used only if replay is also enabled. It takes a transaction hash from the ledger loaded for replay, and will cause a specific line to be hit in Transactor.cpp, right before the selected transaction is applied.
When rippled initiates a connection to SQLite3, rippled sends a "PRAGMA"
statement defining the maximum number of pages allowed in the database.
Update the max_page_count so it is consistent with the default for newer
versions of SQLite3. Increasing max_page_count is critical for keeping
full history servers online.
Fix#5102
Price Oracle data-series logic uses `unordered_map` to update the Oracle object.
This results in different servers disagreeing on the order of that hash table.
Consequently, the generated ledgers will have different hashes.
The fix uses `map` instead to guarantee the order of the token pairs
in the data-series.
Due to the rounding, LPTokenBalance of the last
Liquidity Provider (LP), might not match this LP's
trustline balance. This fix sets LPTokenBalance on
last LP withdrawal to this LP's LPToken trustline
balance.
Single path AMM offer has to factor in the transfer in rate
when calculating the upper bound quality and the quality function
because single path AMM's offer quality is not constant.
This fix factors in the transfer fee in
BookStep::adjustQualityWithFees().
* Fix AMM offer rounding and low quality LOB offer blocking AMM:
A single-path AMM offer with account offer on DEX, is always generated
starting with the takerPays first, which is rounded up, and then
the takerGets, which is rounded down. This rounding ensures that the pool's
product invariant is maintained. However, when one of the offer's side
is XRP, this rounding can result in the AMM offer having a lower
quality, potentially causing offer generation to fail if the quality
is lower than the account's offer quality.
To address this issue, the proposed fix adjusts the offer generation process
to start with the XRP side first and always rounds it down. This results
in a smaller offer size, improving the offer's quality. Regardless if the offer
has XRP or not, the rounding is done so that the offer size is minimized.
This change still ensures the product invariant, as the other generated
side is the exact result of the swap-in or swap-out equations.
If a liquidity can be provided by both AMM and LOB offer on offer crossing
then AMM offer is generated so that it matches LOB offer quality. If LOB
offer quality is less than limit quality then generated AMM offer quality
is also less than limit quality and the offer doesn't cross. To address
this issue, if LOB quality is better than limit quality then use LOB
quality to generate AMM offer. Otherwise, don't use the quality to generate
AMM offer. In this case, limitOut() function in StrandFlow limits
the out amount to match strand's quality to limit quality and consume
maximum AMM liquidity.
Rounding in the payment engine is causing an assert to sometimes fire
with "dust" amounts. This is causing issues when running debug builds of
rippled. This issue will be addressed, but the assert is no longer
serving its purpose.
The AMM has an invariant for swaps where:
new_balance_1*new_balance_2 >= old_balance_1*old_balance_2
Due to rounding, this invariant could sometimes be violated (although by
very small amounts).
This patch introduces an amendment `fixAMMRounding` that changes the
rounding to always favor the AMM. Doing this should maintain the
invariant.
Co-authored-by: Bronek Kozicki
Co-authored-by: thejohnfreeman
It can be difficult to make transaction breaking changes to low level
code because the low level code does not have access to a ledger and the
current activated amendments in that ledger (the "rules"). This patch
adds global access to the current ledger rules as a `std::optional`. If
the optional is not seated, then there is no active transaction.
The `rotateWithLock` function holds a lock while it calls a callback
function that's passed in by the caller. This is a problematic design
that needs to be used very carefully. In this case, at least one caller
passed in a callback that eventually relocks the mutex on the same
thread, causing UB (a deadlock was observed). The caller was from
SHAMapStoreImpl, and it called `clearCaches`. This `clearCaches` can
potentially call `fetchNodeObject`, which tried to relock the mutex.
This patch resolves the issue by changing the mutex type to a
`recursive_mutex`. Ideally, the code should be rewritten so it doesn't
hold the mutex during the callback and the mutex should be changed back
to a regular mutex.
Co-authored-by: Ed Hennis <ed@ripple.com>
