enable soft-fork2 conditions (incl. ASSERT_BEFORE)

[arvidn]

This patch re-enables soft-fork 2 and implements the new conditions and rules.

soft fork 2

Soft-fork 2 makes the following changes, once activated:

1. Change the timestamp ASSERT_SECONDS_* conditions compare against, from the current block's timestamp to the previous transaction block's timestamp. This is to make it consistent with the ASSERT_HEIGHT_* conditions, which already compare against the previous transaction block's height. It also reduces any incentive a farmer may have to be dishonest about which timestamp it puts on a new block.
2. Add ASSERT_MY_BIRTH_SECONDS and ASSERT_MY_BIRTH_HEIGHT, to ensure the coin being spent were created and the specified time or height.
3. Add ASSERT_CONCURRENT_SPEND and ASSERT_CONCURRENT_PUZZLE to ensure that a specified coin ID or puzzle hash is being spent in the same block/spend-bundle as the coin spend emitting this condition.
4. Add ASSERT_EPHEMERAL to ensure that the coin being spent was created in the same block as it's being spent.
5. Add ASSERT_BEFORE_HEIGHT_* and ASSERT_BEFORE_SECONDS_* conditions, which have the opposite meaning as the existing ASSERT_HEIGHT_* and ASSERT_SECONDS_* conditions.
6. Disallow relative time lock conditions on ephemeral coin spends. i.e. coins that are created and spent in the same block, have restrictions on which kinds of conditions they may emit. Specifically, ASSERT_*_RELATIVE, ASSERT_BEFORE_*_RELATIVE, ASSERT_MY_BIRTH_* are not allowed.

Most new conditions have been implemented in chia_rs and won't really show up in this PR.

Review

This PR is made up of 8 commits. They are highly recommended to be reviewed one at a time, in commit order:

re-enable soft-fork 2 logic

This just restores the SOFT_FORK2_HEIGHT configuration, for the block height when to activate the soft-fork. Additionally, since the new conditions are enabled at a specific height only, and not by mempool-mode, callers in mempool mode also need to specify the block height. So it's made non-optional and callers were fixed-up.

blockchain time-lock test

Most time lock tests have been on ephemeral coins, since that is the edge case that needs the most coverage. However, since we're making more changes to the ASSERT_SECONDS_* conditions as well as disallowing relative time locks on ephemeral coins, some of those test cases will become quite uninteresting. So, this patch adds another test that spends a normal coin (i.e. not ephemeral) to cover common cases. This lets us clearly see the effect of the soft-fork changes.

soft-fork rule to use previous transaction block's timestamp

This makes the change to use the previous transaction block's timestamp. The mempool is not really affected, as it's always used the previous transaction block anyway. It's slightly simplified though. The effect is made visible in the new unit test.

bump chia_rs

This brings in the new ASSERT_EPHEMERAL condition and the new rule to disallow relative time locks on ephemeral spends. These are controlled by separate feature flags to chia_rs, this is because the new rule for ephemeral coins should be enabled in mempool-mode immediately, but the new conditions should not be enabled until we reach the activation height. The change to disallow relative time locks on ephemeral spends will make some of the existing test cases "uninteresting", since they will all fail now.

This also brings in two new error codes: ASSERT_EPHEMERAL_FAILED and EPHEMERAL_RELATIVE_CONDITION

ASSERT_BEFORE support in mempool_check_time_locks()

This function is the one that enforces the time-lock conditions in both consensus code and in mempool. With support for this, the unit tests also need to gain new test cases for the new conditions.

ASSERT_BEFORE support in compute_assert_height()

This function is used by the mempool to organize mempool items by when they may become valid (and now also when they will become invalid). The function previously only returned the absolute assert height condition (relative asserts were boiled down the the absolute height). With this patch, it's extended to also compute before_seconds and before_height, which define when a transaction becomes invalid, and should be evicted from the mempool.

ASSERT_BEFORE support in the mempool

The mempool needs the new functionality to expire transactions whose assert-before conditions become invalid. This is where the sqlite index in Mempool comes in handy, to reliably eject expired mempool items.

timelock rule

With the new conditions, we need a new replace-by-fee rule. In order to replace one or more existing MempoolItems in the mempool, the timelock conditions must be identical. This patch implements this change and adds test coverage.

New conditions in soft-fork 2

Name	Valid if	Compares against	cmp	Allowed in ephemeral
ASSERT_HEIGHT_RELATIVE	previous transaction block’s height >= the coin’s birth height + the condition argument.	Previous tx-block	>=	❌
ASSERT_HEIGHT_ABSOLUTE	previous transaction block’s height >= the condition argument.	Previous tx-block	>=	✅
ASSERT_SECONDS_RELATIVE	previous transaction block’s timestamp >= the coin’s birth timestamp + the condition argument	Previous tx-block	>=	❌
ASSERT_SECONDS_ABSOLUTE	previous transaction block’s timestamp >= the condition argument	Previous tx-block	>=	✅
ASSERT_BEFORE_HEIGHT_RELATIVE	previous transaction block’s height is < the coin’s birth height + the condition argument.	Previous tx-block	<	❌
ASSERT_BEFORE_HEIGHT_ABSOLUTE	previous transaction block’s height is < the condition argument.	Previous tx-block	<	✅
ASSERT_BEFORE_SECONDS_RELATIVE	previous transaction block’s timestamp is < the coin’s birth timestamp + the condition argument	Previous tx-block	<	❌
ASSERT_BEFORE_SECONDS_ABSOLUTE	previous transaction block’s timestamp is < the condition argument	Previous tx-block	<	✅
ASSERT_EPHEMERAL	This coin is both created and spent in the same block	Current block	=	✅
ASSERT_MY_BIRTH_HEIGHT	The coin’s birth height is the same as the condition argument	-	=	❌
ASSERT_MY_BIRTH_SECONDS	The coin’s birth timestamp is the same as the condition argument	-	=	❌

references

For more details on the implementation of the other soft-fork 2 conditions, see the PR on chia_rs:

name	PR link
assert not ephemeral (for relative timelocks)	Chia-Network/chia_rs#150
Add ASSERT_EPHEMERAL condition	Chia-Network/chia_rs#149
ASSERT_MY_BIRTH_*	Chia-Network/chia_rs#144
Fix edge cases in parsing ASSERT_BEFORE_*	Chia-Network/chia_rs#140
Add more checks for impossible constraints	Chia-Network/chia_rs#135
ASSERT_CONCURRENT_PUZZLE	Chia-Network/chia_rs#134
ASSERT_CONCURRENT_SPEND	Chia-Network/chia_rs#133
ASSERT_BEFORE_*	Chia-Network/chia_rs#131

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