bf57746c3b
This existing code for calculating treasury spend window values, namely CalculateTSpendWindowStart and CalculateTSpendWindowEnd, has a couple of footguns: - The starting value calculation returns totally invalid values without an error when provided with a expiry that is prior to the first voting window - Expiry values that are invalid for the start calc are valid for the end calc even though they should not be As a result, the code for handling the error paths in the rpc server and mining code produces error messages that don't make sense in some cases because they blindly print the start value without checking the error. To remove the aforementioned footguns and also address the incorrect error messages, the following overview of changes are made: - Replaces the CalculateTSpendWindowStart and CalculateTSpendWindowEnd functions with a single combined CalcTSpendWindow function that properly checks for expiries before the first possible voting interval - Modifies the returned errors to match the new reality - Shortens the prefix to Calc to match the rest of the function names in the package - Updates the incorrect error handling paths to avoid reporting the values that are not guaranteed to be meaningful and modifies the error messages to be more consistent - Adds a comprehensive set of tests for the new function Note that in addition to addressing the aforementioned issues, this approach has at least a couple of other benefits: - It is more efficient to have a single function with a single bounds check - Almost all callers outside of the tests need both the start and end value anyway, so it allows more compact code Finally, this updates all callers in the repository accordingly. |
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| .. | ||
| doc.go | ||
| error.go | ||
| log.go | ||
| mempool_test.go | ||
| mempool.go | ||
| policy_test.go | ||
| policy.go | ||
| README.md | ||
mempool
Package mempool provides a policy-enforced pool of unmined Decred transactions.
A key responsibility of the Decred network is mining transactions – regular transactions and stake transactions – into blocks. In order to facilitate this, the mining process relies on having a readily-available source of transactions to include in a block that is being solved.
At a high level, this package satisfies that requirement by providing an in-memory pool of fully validated transactions that can also optionally be further filtered based upon a configurable policy.
The Policy configuration options has flags that control whether or not "standard" transactions and old votes are accepted into the mempool. In essence, a "standard" transaction is one that satisfies a fairly strict set of requirements that are largely intended to help provide fair use of the system to all users. It is important to note that what is considered to be a "standard" transaction changes over time as policy and consensus rules evolve. For some insight, at the time of this writing, an example of some of the criteria that are required for a transaction to be considered standard are that it is of the most-recently supported version, finalized, does not exceed a specific size, and only consists of specific script forms.
Since this package does not deal with other Decred specifics such as network communication and transaction relay, it returns a list of transactions that were accepted which gives the caller a high level of flexibility in how they want to proceed. Typically, this will involve things such as relaying the transactions to other peers on the network and notifying the mining process that new transactions are available.
Feature Overview
The following is a quick overview of the major features. It is not intended to be an exhaustive list.
- Maintain a pool of fully validated transactions
- Reject non-fully-spent duplicate transactions
- Reject coinbase transactions
- Reject double spends (both from the chain and other transactions in pool)
- Reject invalid transactions according to the network consensus rules
- Full script execution and validation with signature cache support
- Individual transaction query support
- Stake transaction support (ticket purchases, votes and revocations)
- Option to accept or reject old votes
- Orphan transaction support (transactions that spend from unknown outputs)
- Configurable limits (see transaction acceptance policy)
- Automatic addition of orphan transactions that are no longer orphans as new transactions are added to the pool
- Individual orphan transaction query support
- Configurable transaction acceptance policy
- Option to accept or reject standard transactions
- Option to accept or reject transactions based on priority calculations
- Rate limiting of low-fee and free transactions
- Non-zero fee threshold
- Max signature operations per transaction
- Max orphan transaction size
- Max number of orphan transactions allowed
- Additional metadata tracking for each transaction
- Timestamp when the transaction was added to the pool
- Most recent block height when the transaction was added to the pool
- The fee the transaction pays
- The starting priority for the transaction
- Manual control of transaction removal
- Recursive removal of all dependent transactions
License
Package mempool is licensed under the copyfree ISC License.