CHIA-3737 Simplify BundleCoinSpend's tracking of fast forward spends (#20069)

Simplify BundleCoinSpend's tracking of fast forward spends.

Author: AmineKhaldi

chia/_tests/core/mempool/test_mempool_manager.py

@@ -579,7 +579,6 @@ def make_bundle_spends_map_and_fee(
         bundle_coin_spends[coin_id] = BundleCoinSpend(
             coin_spend=coin_spend,
             eligible_for_dedup=bool(spend_conds.flags & ELIGIBLE_FOR_DEDUP),
-            eligible_for_fast_forward=bool(spend_conds.flags & ELIGIBLE_FOR_FF),
             additions=additions,
             cost=uint64(spend_conds.condition_cost + spend_conds.execution_cost),
             latest_singleton_lineage=UnspentLineageInfo(coin_id, coin_spend.coin.parent_coin_info, bytes32([0] * 32))
@@ -890,9 +889,13 @@ def mk_bcs(coin_spend: CoinSpend, flags: int = 0) -> BundleCoinSpend:
     return BundleCoinSpend(
         coin_spend=coin_spend,
         eligible_for_dedup=bool(flags & ELIGIBLE_FOR_DEDUP),
-        eligible_for_fast_forward=bool(flags & ELIGIBLE_FOR_FF),
         additions=[],
         cost=uint64(0),
+        latest_singleton_lineage=UnspentLineageInfo(
+            coin_spend.coin.name(), coin_spend.coin.parent_coin_info, bytes32([0] * 32)
+        )
+        if flags & ELIGIBLE_FOR_FF
+        else None,
     )
 
 
@@ -1802,16 +1805,16 @@ async def test_bundle_coin_spends() -> None:
         assert mi123e.bundle_coin_spends[coins[i].name()] == BundleCoinSpend(
             coin_spend=sb123.coin_spends[i],
             eligible_for_dedup=False,
-            eligible_for_fast_forward=False,
             additions=[Coin(coins[i].name(), IDENTITY_PUZZLE_HASH, coins[i].amount)],
             cost=uint64(ConditionCost.CREATE_COIN.value + ConditionCost.AGG_SIG.value + execution_cost),
+            latest_singleton_lineage=None,
         )
     assert mi123e.bundle_coin_spends[coins[3].name()] == BundleCoinSpend(
         coin_spend=eligible_sb.coin_spends[0],
         eligible_for_dedup=True,
-        eligible_for_fast_forward=False,
         additions=[Coin(coins[3].name(), IDENTITY_PUZZLE_HASH, coins[3].amount)],
         cost=uint64(ConditionCost.CREATE_COIN.value + execution_cost),
+        latest_singleton_lineage=None,
     )
 
 
@@ -2463,7 +2466,7 @@ async def test_new_peak_ff_eviction(
     item = mempool_manager.get_mempool_item(bundle.name())
     assert item is not None
     singleton_name = singleton_spend.coin.name()
-    assert item.bundle_coin_spends[singleton_name].eligible_for_fast_forward
+    assert item.bundle_coin_spends[singleton_name].supports_fast_forward
     latest_singleton_lineage = item.bundle_coin_spends[singleton_name].latest_singleton_lineage
     assert latest_singleton_lineage is not None
     assert latest_singleton_lineage.coin_id == singleton_name
@@ -2495,7 +2498,7 @@ async def test_new_peak_ff_eviction(
     else:
         item = mempool_manager.get_mempool_item(bundle.name())
         assert item is not None
-        assert item.bundle_coin_spends[singleton_spend.coin.name()].eligible_for_fast_forward
+        assert item.bundle_coin_spends[singleton_spend.coin.name()].supports_fast_forward
         latest_singleton_lineage = item.bundle_coin_spends[singleton_spend.coin.name()].latest_singleton_lineage
         assert latest_singleton_lineage is not None
         assert latest_singleton_lineage.coin_id == singleton_spend.coin.name()
@@ -2552,9 +2555,9 @@ async def test_multiple_ff(use_optimization: bool) -> None:
 
     item = mempool_manager.get_mempool_item(bundle.name())
     assert item is not None
-    assert item.bundle_coin_spends[singleton_spend1.coin.name()].eligible_for_fast_forward
-    assert item.bundle_coin_spends[singleton_spend2.coin.name()].eligible_for_fast_forward
-    assert not item.bundle_coin_spends[coin_spend.coin.name()].eligible_for_fast_forward
+    assert item.bundle_coin_spends[singleton_spend1.coin.name()].supports_fast_forward
+    assert item.bundle_coin_spends[singleton_spend2.coin.name()].supports_fast_forward
+    assert not item.bundle_coin_spends[coin_spend.coin.name()].supports_fast_forward
 
     # spend the singleton coin2 and make coin3 the latest version
     coins.update_lineage(singleton_ph, singleton_spend3.coin)
@@ -2616,7 +2619,7 @@ async def test_advancing_ff(use_optimization: bool) -> None:
     item = mempool_manager.get_mempool_item(bundle.name())
     assert item is not None
     spend = item.bundle_coin_spends[spend_a.coin.name()]
-    assert spend.eligible_for_fast_forward
+    assert spend.supports_fast_forward
     assert spend.latest_singleton_lineage is not None
     assert spend.latest_singleton_lineage.coin_id == spend_a.coin.name()
 
@@ -2628,7 +2631,7 @@ async def test_advancing_ff(use_optimization: bool) -> None:
     item = mempool_manager.get_mempool_item(bundle.name())
     assert item is not None
     spend = item.bundle_coin_spends[spend_a.coin.name()]
-    assert spend.eligible_for_fast_forward
+    assert spend.supports_fast_forward
     assert spend.latest_singleton_lineage is not None
     assert spend.latest_singleton_lineage.coin_id == spend_b.coin.name()
 
@@ -2640,7 +2643,7 @@ async def test_advancing_ff(use_optimization: bool) -> None:
     item = mempool_manager.get_mempool_item(bundle.name())
     assert item is not None
     spend = item.bundle_coin_spends[spend_a.coin.name()]
-    assert spend.eligible_for_fast_forward
+    assert spend.supports_fast_forward
     assert spend.latest_singleton_lineage is not None
     assert spend.latest_singleton_lineage.coin_id == spend_c.coin.name()
 

chia/_tests/core/mempool/test_singleton_fast_forward.py

@@ -52,7 +52,7 @@ def test_process_fast_forward_spends_nothing_to_do() -> None:
     sb = spend_bundle_from_conditions(conditions, TEST_COIN, sig)
     item = mempool_item_from_spendbundle(sb)
     # This coin is not eligible for fast forward
-    assert item.bundle_coin_spends[TEST_COIN_ID].eligible_for_fast_forward is False
+    assert not item.bundle_coin_spends[TEST_COIN_ID].supports_fast_forward
     internal_mempool_item = InternalMempoolItem(sb, item.conds, item.height_added_to_mempool, item.bundle_coin_spends)
     original_version = dataclasses.replace(internal_mempool_item)
     singleton_ff = SingletonFastForward()
@@ -63,28 +63,6 @@ def test_process_fast_forward_spends_nothing_to_do() -> None:
     assert bundle_coin_spends == original_version.bundle_coin_spends
 
 
-def test_process_fast_forward_spends_unknown_ff() -> None:
-    """
-    This tests the case when we process for the first time but we are unable
-    to lookup the latest version from the item's latest singleton lineage
-    """
-    test_coin = Coin(TEST_COIN_ID, IDENTITY_PUZZLE_HASH, uint64(1))
-    conditions = [[ConditionOpcode.CREATE_COIN, IDENTITY_PUZZLE_HASH, 1]]
-    sb = spend_bundle_from_conditions(conditions, test_coin)
-    item = mempool_item_from_spendbundle(sb)
-    # The coin is eligible for fast forward
-    assert item.bundle_coin_spends[test_coin.name()].eligible_for_fast_forward is True
-    item.bundle_coin_spends[test_coin.name()].latest_singleton_lineage = None
-    internal_mempool_item = InternalMempoolItem(sb, item.conds, item.height_added_to_mempool, item.bundle_coin_spends)
-    singleton_ff = SingletonFastForward()
-    # We have no fast forward records yet, so we'll process this coin for the
-    # first time here, but the item's latest singleton lineage returns None
-    with pytest.raises(ValueError, match="Cannot proceed with singleton spend fast forward"):
-        singleton_ff.process_fast_forward_spends(
-            mempool_item=internal_mempool_item, height=TEST_HEIGHT, constants=DEFAULT_CONSTANTS
-        )
-
-
 def test_process_fast_forward_spends_latest_unspent() -> None:
     """
     This tests the case when we are the latest singleton version already, so
@@ -103,7 +81,7 @@ def test_process_fast_forward_spends_latest_unspent() -> None:
     conditions = [[ConditionOpcode.CREATE_COIN, IDENTITY_PUZZLE_HASH, test_amount]]
     sb = spend_bundle_from_conditions(conditions, test_coin)
     item = mempool_item_from_spendbundle(sb)
-    assert item.bundle_coin_spends[test_coin.name()].eligible_for_fast_forward is True
+    assert item.bundle_coin_spends[test_coin.name()].supports_fast_forward
     item.bundle_coin_spends[test_coin.name()].latest_singleton_lineage = test_unspent_lineage_info
     internal_mempool_item = InternalMempoolItem(sb, item.conds, item.height_added_to_mempool, item.bundle_coin_spends)
     original_version = dataclasses.replace(internal_mempool_item)
@@ -168,12 +146,12 @@ def test_perform_the_fast_forward() -> None:
         "517b0dadb0c310ded24dd86dff8205398080ff808080"
     )
     test_coin_spend = CoinSpend(test_coin, test_puzzle_reveal, test_solution)
-    test_spend_data = BundleCoinSpend(test_coin_spend, False, True, [test_child_coin], uint64(0))
     test_unspent_lineage_info = UnspentLineageInfo(
         coin_id=latest_unspent_coin.name(),
         parent_id=latest_unspent_coin.parent_coin_info,
         parent_parent_id=test_child_coin.parent_coin_info,
     )
+    test_spend_data = BundleCoinSpend(test_coin_spend, False, [test_child_coin], uint64(0), test_unspent_lineage_info)
     # Start from a fresh state of fast forward spends
     fast_forward_spends: dict[bytes32, UnspentLineageInfo] = {}
     # Perform the fast forward on the test coin (the grandparent)

chia/full_node/eligible_coin_spends.py

@@ -196,7 +196,7 @@ def process_fast_forward_spends(
         new_bundle_coin_spends = {}
         fast_forwarded_spends = 0
         for coin_id, spend_data in mempool_item.bundle_coin_spends.items():
-            if not spend_data.eligible_for_fast_forward:
+            if not spend_data.supports_fast_forward:
                 # Nothing to do for this spend, moving on
                 new_coin_spends.append(spend_data.coin_spend)
                 new_bundle_coin_spends[coin_id] = spend_data
@@ -210,8 +210,7 @@ def process_fast_forward_spends(
             unspent_lineage_info = self.fast_forward_spends.get(spend_data.coin_spend.coin.puzzle_hash)
             if unspent_lineage_info is None:
                 # We didn't, so let's check the item's latest lineage info
-                if spend_data.latest_singleton_lineage is None:
-                    raise ValueError("Cannot proceed with singleton spend fast forward.")
+                assert spend_data.latest_singleton_lineage is not None
                 unspent_lineage_info = spend_data.latest_singleton_lineage
                 # See if we're the most recent version
                 if unspent_lineage_info.coin_id == coin_id:
@@ -235,9 +234,9 @@ def process_fast_forward_spends(
                 new_bundle_coin_spends[new_coin_spend.coin.name()] = BundleCoinSpend(
                     coin_spend=new_coin_spend,
                     eligible_for_dedup=spend_data.eligible_for_dedup,
-                    eligible_for_fast_forward=spend_data.eligible_for_fast_forward,
                     additions=patched_additions,
                     cost=spend_data.cost,
+                    latest_singleton_lineage=self.fast_forward_spends.get(spend_data.coin_spend.coin.puzzle_hash),
                 )
                 # Update the list of coins spends that will make the new fast
                 # forward spend bundle
@@ -258,9 +257,9 @@ def process_fast_forward_spends(
             new_bundle_coin_spends[new_coin_spend.coin.name()] = BundleCoinSpend(
                 coin_spend=new_coin_spend,
                 eligible_for_dedup=spend_data.eligible_for_dedup,
-                eligible_for_fast_forward=spend_data.eligible_for_fast_forward,
                 additions=patched_additions,
                 cost=spend_data.cost,
+                latest_singleton_lineage=self.fast_forward_spends.get(spend_data.coin_spend.coin.puzzle_hash),
             )
             # Update the list of coins spends that make the new fast forward bundle
             new_coin_spends.append(new_coin_spend)

chia/full_node/mempool.py

@@ -611,7 +611,7 @@ def create_bundle_from_mempool_items(
                     # might fit, but we also want to avoid spending too much
                     # time on potentially expensive ones, hence this shortcut.
                     if any(
-                        sd.eligible_for_dedup or sd.eligible_for_fast_forward for sd in item.bundle_coin_spends.values()
+                        sd.eligible_for_dedup or sd.supports_fast_forward for sd in item.bundle_coin_spends.values()
                     ):
                         log.info(f"Skipping transaction with dedup or FF spends {name}")
                         continue

chia/full_node/mempool_manager.py

@@ -243,7 +243,7 @@ def check_removals(
     conflicts = set()
     for coin_id, coin_bcs in bundle_coin_spends.items():
         # 1. Checks if it's been spent already
-        if removals[coin_id].spent and not coin_bcs.eligible_for_fast_forward:
+        if removals[coin_id].spent and not coin_bcs.supports_fast_forward:
             return Err.DOUBLE_SPEND, []
 
         # 2. Checks if there's a mempool conflict
@@ -269,12 +269,12 @@ def check_removals(
                     return Err.INVALID_SPEND_BUNDLE, []
             # if the spend we're adding to the mempool is not DEDUP nor FF, it's
             # just a regular conflict
-            if not coin_bcs.eligible_for_fast_forward and not coin_bcs.eligible_for_dedup:
+            if not coin_bcs.supports_fast_forward and not coin_bcs.eligible_for_dedup:
                 conflicts.add(item)
 
             # if the spend we're adding is FF, but there's a conflicting spend
             # that isn't FF, they can't be chained, so that's a conflict
-            elif coin_bcs.eligible_for_fast_forward and not conflict_bcs.eligible_for_fast_forward:
+            elif coin_bcs.supports_fast_forward and not conflict_bcs.supports_fast_forward:
                 conflicts.add(item)
 
             # if the spend we're adding is DEDUP, but there's a conflicting spend
@@ -611,8 +611,7 @@ async def validate_spend_bundle(
                 return Err.INVALID_COIN_SOLUTION, None, []
 
             lineage_info = None
-            eligible_for_ff = bool(spend_conds.flags & ELIGIBLE_FOR_FF) and supports_fast_forward(coin_spend)
-            if eligible_for_ff:
+            if bool(spend_conds.flags & ELIGIBLE_FOR_FF) and supports_fast_forward(coin_spend):
                 # Make sure the fast forward spend still has a version that is
                 # still unspent, because if the singleton has been spent in a
                 # non-FF spend, this fast forward spend will never become valid.
@@ -622,8 +621,6 @@ async def validate_spend_bundle(
                 # spent_index will also fail this test, and such spends will
                 # fall back to be treated as non-FF spends.
                 lineage_info = await get_unspent_lineage_info_for_puzzle_hash(spend_conds.puzzle_hash)
-                if lineage_info is None:
-                    eligible_for_ff = False
 
             spend_additions = []
             for puzzle_hash, amount, _ in spend_conds.create_coin:
@@ -635,7 +632,6 @@ async def validate_spend_bundle(
             bundle_coin_spends[coin_id] = BundleCoinSpend(
                 coin_spend=coin_spend,
                 eligible_for_dedup=bool(spend_conds.flags & ELIGIBLE_FOR_DEDUP),
-                eligible_for_fast_forward=eligible_for_ff,
                 additions=spend_additions,
                 cost=uint64(spend_conds.condition_cost + spend_conds.execution_cost),
                 latest_singleton_lineage=lineage_info,
@@ -644,7 +640,7 @@ async def validate_spend_bundle(
         # fast forward spends are only allowed when bundled with other, non-FF, spends
         # in order to evict an FF spend, it must be associated with a normal
         # spend that can be included in a block or invalidated some other way
-        if all([s.eligible_for_fast_forward for s in bundle_coin_spends.values()]):
+        if all([s.supports_fast_forward for s in bundle_coin_spends.values()]):
             return Err.INVALID_SPEND_BUNDLE, None, []
 
         removal_record_dict: dict[bytes32, CoinRecord] = {}
@@ -1062,7 +1058,7 @@ def can_replace(
             if coin_id not in removal_names:
                 log.debug("Rejecting conflicting tx as it does not spend conflicting coin %s", coin_id)
                 return False
-            if bcs.eligible_for_fast_forward:
+            if bcs.supports_fast_forward:
                 existing_ff_spends.add(bytes32(coin_id))
             if bcs.eligible_for_dedup:
                 existing_dedup_spends.add(bytes32(coin_id))
@@ -1113,7 +1109,7 @@ def can_replace(
 
     if len(existing_ff_spends) > 0 or len(existing_dedup_spends) > 0:
         for coin_id, bcs in new_item.bundle_coin_spends.items():
-            if not bcs.eligible_for_fast_forward and coin_id in existing_ff_spends:
+            if not bcs.supports_fast_forward and coin_id in existing_ff_spends:
                 log.debug("Rejecting conflicting tx due to changing ELIGIBLE_FOR_FF of coin spend %s", coin_id)
                 return False
 

chia/types/mempool_item.py

@@ -22,7 +22,6 @@ class UnspentLineageInfo:
 class BundleCoinSpend:
     coin_spend: CoinSpend
     eligible_for_dedup: bool
-    eligible_for_fast_forward: bool
     additions: list[Coin]
     # cost on the specific solution in this item. The cost includes execution
     # cost and conditions cost, not byte-cost.
@@ -32,7 +31,11 @@ class BundleCoinSpend:
     # current unspent lineage belonging to this singleton, that we would rebase
     # this spend on top of if we were to make a block now
     # When finding MempoolItems by coin ID, we use Coin ID from it if it's set
-    latest_singleton_lineage: Optional[UnspentLineageInfo] = None
+    latest_singleton_lineage: Optional[UnspentLineageInfo]
+
+    @property
+    def supports_fast_forward(self) -> bool:
+        return self.latest_singleton_lineage is not None
 
 
 @dataclass(frozen=True)