This merge commit adds the following code from the
github.com/decred/dcrutil package into a new
github.com/decred/dcrd/dcrutil package:
* Address handling
* Amount type
* AppDataDir func
* bitflags functions
* Block wrapper type
* Hash160 func
* Tx wrapper type
* WIF type
as well as all tests for this code.
The old github.com/decred/dcrutil/hdkeychain package has also been
merged and moved to github.com/decred/dcrd/dcrutil/hdkeychain.
dcrd packages have been updated to use the new packages and the dep
files have been updated for this change.
This adds enforcement of the newly introduced relative time locks via
transaction sequence numbers when considering candidate transactions for
acceptance to the mempool, relaying, and inclusion into block templates.
It also raises the maximum standard transaction version to 2
accordingly. This is acceptable because it is a soft forking change and
the aforementioned areas only enforce policy.
The following is an overview of the changes:
- Modify mempool to consider version 2 transactions standard
- Introduce a new callback to the mempool config for obtaining the
sequence lock for block after the current best chain tip so it can
remain decoupled from the chain
- Update mempool to enforce relative locks on all candidate transactions
- Update the mock chain in the mempool test harness accordingly
This modifies the mempool transaction finality checks to use the past
median time instead of the adjusted network time. This ensures the
standardness rules match the upcoming consensus rules which reject
transactions that are not after the median time of the last several
blocks. Without this change, it is possible for transactions which can
never make it into a block to be admitted to the mempool thereby wasting
memory.
The following is an overview of the changes:
- Introduce a new callback to the mempool config named PastMedianTime
for obtaining the median time for the current best chain so it can
remain decoupled from the chain
- Update the tx finality standardness check to use the callback
- Remove the now unused TimeSource mempool config parameter
- Update the mempool test harness and mock chain to use a mock median time
- Update server to provide a closure for the mempool config that uses
the cached median time for the current best chain to negate any
additional performance impact the new calculations would otherwise
cause from recalculating the median time for every new candidate tx
validation
This modifies the way standard verification flags are handled so that it
is possible to selectively enable them based on the result of agenda
votes.
First, it moves the StandardVerifyFlags constant from the txscript
package to the mempool/policy code and rename it to
BaseStandardVerifyFlags. As the TODO in the comment of the moved
constant indicated, these flags are policy related and thus really
belong in policy. Ideally there would be a completely separate policy
package, but since the policy code currently lives in mempool/policy.go,
the constant has been moved there.
Next, it introduces a new function named standardScriptVerifyFlags,
which accepts the chain as an argument and, for now, just returns the
BaseStandardVerifyFlags along with a nil error. This will allow
additional flags to be selectively enabled depending on the result of an
agenda vote.
Finally, it updates the mempool policy struct to require a closure for
obtaining the flags so it can remain decoupled from the chain which in
turn allows easier and more robust unit testing of mempool functionality
since it allows a mocks to be used.
This removes the function IsSupportedMsgTxVersion function from wire
since that is a policy decision and does not belong in wire.
It also updates the mempool standard transaction checks to be more
inline with the upstream code such that the maximum supported
transaction version is specified via a field in the mempool policy
configuration struct.
Finally, it adds a new test to the standard transaction tests to ensure
transactions that are not serialized with the full seriaization type are
considered nonstandard.
Upstream commit 15bace88dc.
In addition to the necessary Decred-specific alterations to the existing
upstream code, the merge commit also introduces several new functions on
the fake chain instance to handle the additional capabilities needed by
the Decred mempool such as the NextStakeDifficulty, BlockByHash, and
BestHash functions along with a SubsidyCache instance.
This adds a basic test harness infrastructure for the mempool package
which aims to make writing tests for it much easier.
The harness provides functionality for creating and signing transactions
as well as a fake chain that provides utxos for use in generating valid
transactions and allows an arbitrary chain height to be set. In order
to simplify transaction creation, a single signing key and payment
address is used throughout and a convenience type for spendable outputs
is provided.
The harness is initialized with a spendable coinbase output by default
and the fake chain height set to the maturity height needed to ensure
the provided output is in fact spendable as well as a policy that is
suitable for testing.
Since tests are in the same package and each harness provides a unique
pool and fake chain instance, the tests can safely reach into the pool
policy, or any other state, and change it for a given harness without
affecting the others.
In order to be able to make use of the existing blockchain.Viewpoint
type, a Clone method has been to the UtxoEntry type which allows the
fake chain instance to keep a single view with the actual available
unspent utxos while the mempool ends up fetching a subset of the view
with the specifically requested entries cloned.
To demo the harness, this also contains a couple of tests which make use
of it:
- TestSimpleOrphanChain -- Ensures an entire chain of orphans is
properly accepted and connects up when the missing parent transaction
is added
- TestOrphanRejects -- Ensure orphans are actually rejected when the
flag on ProcessTransactions is set to reject them
