Fix attestation inclusion delay calculation

src/attestation/inclusion_tracker.rs

@@ -0,0 +1,54 @@
+//! Attestation inclusion-delay accounting.
+//!
+//! Inclusion delay is measured in wall-clock slots: the difference between the
+//! slot an attestation was assigned to and the slot of the beacon block that
+//! includes it. Skipped slots still count toward this delay even though no block
+//! exists for those slots.
+
+/// Consensus slot number.
+pub type Slot = u64;
+
+/// Minimum valid attestation inclusion delay, in slots.
+pub const MIN_ATTESTATION_INCLUSION_DELAY: u64 = 1;
+
+/// Delay at which the inclusion-delay reward reaches zero.
+pub const MAX_ATTESTATION_INCLUSION_DELAY: u64 = 32;
+
+/// Return the number of wall-clock slots from `start` to `end`.
+///
+/// This intentionally does not inspect produced blocks. A skipped slot advances
+/// wall-clock time and therefore increases attestation inclusion delay.
+pub fn wall_slots_between(start: Slot, end: Slot) -> u64 {
+    end.saturating_sub(start)
+}
+
+/// Compute the inclusion delay for an attestation assigned to
+/// `attestation_slot` and included in a block at `block_slot`.
+pub fn compute_inclusion_delay(attestation_slot: Slot, block_slot: Slot) -> u64 {
+    wall_slots_between(attestation_slot, block_slot)
+}
+
+/// Compute the inclusion-delay reward for `delay` from `max_reward`.
+///
+/// Rewards are maximal at delay 1 and linearly decrease to zero at delay 32.
+pub fn update_delay_rewards(delay: u64, max_reward: u64) -> u64 {
+    if delay < MIN_ATTESTATION_INCLUSION_DELAY {
+        return 0;
+    }
+
+    if delay >= MAX_ATTESTATION_INCLUSION_DELAY {
+        return 0;
+    }
+
+    let remaining = MAX_ATTESTATION_INCLUSION_DELAY - delay;
+    let reward_span = MAX_ATTESTATION_INCLUSION_DELAY - MIN_ATTESTATION_INCLUSION_DELAY;
+    max_reward.saturating_mul(remaining) / reward_span
+}
+
+/// Convenience helper for callers that have attestation and inclusion slots.
+pub fn delay_reward(attestation_slot: Slot, block_slot: Slot, max_reward: u64) -> u64 {
+    update_delay_rewards(
+        compute_inclusion_delay(attestation_slot, block_slot),
+        max_reward,
+    )
+}

src/attestation/mod.rs

@@ -2,5 +2,6 @@
 
 pub mod bitfield;
 pub mod bls_aggregator;
+pub mod inclusion_tracker;
 pub mod key_registry;
 pub mod verifier;

src/consensus/fork_choice.rs

@@ -0,0 +1,31 @@
+//! Fork-choice branch weighting.
+
+use crate::attestation::inclusion_tracker::{delay_reward, Slot};
+
+/// Attestation data needed to weight a branch.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct IncludedAttestation {
+    /// Slot the attestation was assigned to.
+    pub attestation_slot: Slot,
+    /// Slot of the block that included the attestation.
+    pub inclusion_slot: Slot,
+    /// Validator or aggregate vote weight before inclusion-delay adjustment.
+    pub validator_weight: u64,
+}
+
+/// Compute a branch's total attestation weight after inclusion-delay rewards.
+///
+/// The calculation depends only on wall-clock attestation/inclusion slots, so
+/// skipped-slot placement between them cannot make a branch appear heavier.
+pub fn branch_weighting(attestations: &[IncludedAttestation], max_delay_reward: u64) -> u64 {
+    attestations
+        .iter()
+        .map(|attestation| {
+            attestation.validator_weight.saturating_add(delay_reward(
+                attestation.attestation_slot,
+                attestation.inclusion_slot,
+                max_delay_reward,
+            ))
+        })
+        .sum()
+}

src/consensus/mod.rs

@@ -0,0 +1,3 @@
+//! Consensus helpers.
+
+pub mod fork_choice;

src/lib.rs

@@ -16,6 +16,7 @@ pub mod slashing_core;
 // signatures cannot be replayed across consensus domains.
 pub mod attestation;
 pub mod crypto;
+pub mod consensus;
 
 // Validator lifecycle and state transition.
 // `validator` provides a deterministic exit queue ordered strictly by

test_snapshots/slashing_core/slashing/tests/monitor_tests/test_event_store_unique_constraint.1.json

@@ -0,0 +1,158 @@
+{
+  "generators": {
+    "address": 2,
+    "nonce": 0
+  },
+  "auth": [
+    []
+  ],
+  "ledger": {
+    "protocol_version": 21,
+    "sequence_number": 0,
+    "timestamp": 0,
+    "network_id": "0000000000000000000000000000000000000000000000000000000000000000",
+    "base_reserve": 0,
+    "min_persistent_entry_ttl": 4096,
+    "min_temp_entry_ttl": 16,
+    "max_entry_ttl": 6312000,
+    "ledger_entries": [
+      [
+        {
+          "contract_data": {
+            "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+            "key": "ledger_key_contract_instance",
+            "durability": "persistent"
+          }
+        },
+        [
+          {
+            "last_modified_ledger_seq": 0,
+            "data": {
+              "contract_data": {
+                "ext": "v0",
+                "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+                "key": "ledger_key_contract_instance",
+                "durability": "persistent",
+                "val": {
+                  "contract_instance": {
+                    "executable": {
+                      "wasm": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
+                    },
+                    "storage": [
+                      {
+                        "key": {
+                          "vec": [
+                            {
+                              "symbol": "Event"
+                            },
+                            {
+                              "address": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAFCT4"
+                            },
+                            {
+                              "u64": 1
+                            }
+                          ]
+                        },
+                        "val": {
+                          "map": [
+                            {
+                              "key": {
+                                "symbol": "created_at"
+                              },
+                              "val": {
+                                "u64": 100
+                              }
+                            },
+                            {
+                              "key": {
+                                "symbol": "node_id"
+                              },
+                              "val": {
+                                "address": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAFCT4"
+                              }
+                            },
+                            {
+                              "key": {
+                                "symbol": "penalty_amount"
+                              },
+                              "val": {
+                                "i128": {
+                                  "hi": 0,
+                                  "lo": 1000
+                                }
+                              }
+                            },
+                            {
+                              "key": {
+                                "symbol": "reasons"
+                              },
+                              "val": {
+                                "vec": [
+                                  {
+                                    "vec": [
+                                      {
+                                        "symbol": "DoubleSigning"
+                                      }
+                                    ]
+                                  }
+                                ]
+                              }
+                            },
+                            {
+                              "key": {
+                                "symbol": "scan_epoch"
+                              },
+                              "val": {
+                                "u64": 1
+                              }
+                            },
+                            {
+                              "key": {
+                                "symbol": "status"
+                              },
+                              "val": {
+                                "vec": [
+                                  {
+                                    "symbol": "Pending"
+                                  }
+                                ]
+                              }
+                            }
+                          ]
+                        }
+                      }
+                    ]
+                  }
+                }
+              }
+            },
+            "ext": "v0"
+          },
+          4095
+        ]
+      ],
+      [
+        {
+          "contract_code": {
+            "hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
+          }
+        },
+        [
+          {
+            "last_modified_ledger_seq": 0,
+            "data": {
+              "contract_code": {
+                "ext": "v0",
+                "hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+                "code": ""
+              }
+            },
+            "ext": "v0"
+          },
+          4095
+        ]
+      ]
+    ]
+  },
+  "events": []
+}