Use ALTAIR_FORK_EPOCH instead of ALTAIR_FORK_SLOT

configs/README.md

@@ -15,7 +15,7 @@ Over time, the need to sync an older state may be deprecated.
 In this case, the prefix on the new constant may be removed, and the old constant will keep a special name before completely being removed.
 
 A previous iteration of forking made use of "timelines", but this collides with the definitions used in the spec (constants for special forking slots, etc.), and was not integrated sufficiently in any of the spec tools or implementations.
-Instead, the config essentially doubles as fork definition now, e.g. changing the value for `ALTAIR_FORK_SLOT` changes the fork.
+Instead, the config essentially doubles as fork definition now, e.g. changing the value for `ALTAIR_FORK_EPOCH` changes the fork.
 
 Another reason to prefer forking through constants is the ability to program a forking moment based on context, instead of being limited to a static slot number.
 

configs/mainnet/altair.yaml

@@ -38,7 +38,7 @@ DOMAIN_CONTRIBUTION_AND_PROOF: 0x09000000
 # 0x01000000
 ALTAIR_FORK_VERSION: 0x01000000
 # TBD
-ALTAIR_FORK_SLOT: 18446744073709551615
+ALTAIR_FORK_EPOCH: 18446744073709551615
 
 
 # Sync protocol

configs/mainnet/merge.yaml

@@ -4,4 +4,4 @@
 # ---------------------------------------------------------------
 MERGE_FORK_VERSION: 0x02000000
 # TBD, temporarily max uint64 value: 2**64 - 1
-MERGE_FORK_SLOT: 18446744073709551615
+MERGE_FORK_EPOCH: 18446744073709551615

configs/mainnet/sharding.yaml

@@ -4,7 +4,7 @@
 # ---------------------------------------------------------------
 SHARDING_FORK_VERSION: 0x03000000
 # TBD, temporarily max uint64 value: 2**64 - 1
-SHARDING_FORK_SLOT: 18446744073709551615
+SHARDING_FORK_EPOCH: 18446744073709551615
 
 
 # Beacon-chain

configs/minimal/altair.yaml

@@ -38,7 +38,7 @@ DOMAIN_CONTRIBUTION_AND_PROOF: 0x09000000
 # [customized] Highest byte set to 0x01 to avoid collisions with mainnet versioning
 ALTAIR_FORK_VERSION: 0x01000001
 # [customized]
-ALTAIR_FORK_SLOT: 18446744073709551615
+ALTAIR_FORK_EPOCH: 18446744073709551615
 
 
 # Sync protocol

configs/minimal/merge.yaml

@@ -4,4 +4,4 @@
 # ---------------------------------------------------------------
 MERGE_FORK_VERSION: 0x02000001
 # TBD, temporarily max uint64 value: 2**64 - 1
-MERGE_FORK_SLOT: 18446744073709551615
+MERGE_FORK_EPOCH: 18446744073709551615

configs/minimal/sharding.yaml

@@ -4,7 +4,7 @@
 # ---------------------------------------------------------------
 SHARDING_FORK_VERSION: 0x03000001
 # TBD, temporarily max uint64 value: 2**64 - 1
-MERGE_FORK_SLOT: 18446744073709551615
+MERGE_FORK_EPOCH: 18446744073709551615
 
 
 # Beacon-chain

specs/altair/fork.md

@@ -26,17 +26,17 @@ Warning: this configuration is not definitive.
 | Name | Value |
 | - | - |
 | `ALTAIR_FORK_VERSION` | `Version('0x01000000')` |
-| `ALTAIR_FORK_SLOT` | `Slot(18446744073709551615)` **TBD** |
+| `ALTAIR_FORK_EPOCH` | `Epoch(18446744073709551615)` **TBD** |
 
 ## Fork to Altair
 
 ### Fork trigger
 
-TBD. Social consensus, along with state conditions such as epoch boundary, finality, deposits, active validator count, etc. may be part of the decision process to trigger the fork. For now we assume the condition will be triggered at slot `ALTAIR_FORK_SLOT`, where `ALTAIR_FORK_SLOT % SLOTS_PER_EPOCH == 0`.
+TBD. Social consensus, along with state conditions such as epoch boundary, finality, deposits, active validator count, etc. may be part of the decision process to trigger the fork. For now we assume the condition will be triggered at epoch `ALTAIR_FORK_EPOCH`.
 
 ### Upgrading the state
 
-After `process_slots` of Phase 0 finishes, if `state.slot == ALTAIR_FORK_SLOT`, an irregular state change is made to upgrade to Altair.
+After `process_slots` of Phase 0 finishes, if `state.slot % SLOTS_PER_EPOCH == 0` and `compute_epoch_at_slot(state.slot) == ALTAIR_FORK_EPOCH`, an irregular state change is made to upgrade to Altair.
 
 ```python
 def upgrade_to_altair(pre: phase0.BeaconState) -> BeaconState:

specs/das/fork-choice.md

@@ -37,7 +37,7 @@ def get_new_dependencies(state: BeaconState) -> Set[DataCommitment]:
 
 ```python
 def get_all_dependencies(store: Store, block: BeaconBlock) -> Set[DataCommitment]:
-    if block.slot < SHARDING_FORK_SLOT:
+    if compute_epoch_at_slot(block.slot) < SHARDING_FORK_EPOCH:
         return set()
     else:
         latest = get_new_dependencies(store.block_states[hash_tree_root(block)])

tests/core/pyspec/eth2spec/test/helpers/state.py

@@ -42,9 +42,10 @@ def transition_to_slot_via_block(spec, state, slot):
 
 def transition_to_valid_shard_slot(spec, state):
     """
-    Transition to slot `spec.SHARDING_FORK_SLOT + 1` and fork at `spec.SHARDING_FORK_SLOT`.
+    Transition to slot `compute_epoch_at_slot(spec.SHARDING_FORK_EPOCH) + 1`
+    and fork at `compute_epoch_at_slot(spec.SHARDING_FORK_EPOCH)`.
     """
-    transition_to(spec, state, spec.SHARDING_FORK_SLOT)
+    transition_to(spec, state, spec.compute_epoch_at_slot(spec.SHARDING_FORK_EPOCH))
     next_slot(spec, state)