Merge pull request #81 from djrtwo/bugfix/dynasty_wei_delta_in_slashing

[bugfix] dynasty_wei_delta errors in slashing

casper/contracts/simple_casper.v.py

@@ -481,13 +481,16 @@ def slash(vote_msg_1: bytes <= 1024, vote_msg_2: bytes <= 1024):
     # Log slashing
     log.Slash(msg.sender, self.validators[validator_index_1].withdrawal_addr, validator_index_1, slashing_bounty, deposit_destroyed)
 
-    deposit: decimal(wei/m) = self.validators[validator_index_1].deposit
-    self.dynasty_wei_delta[self.dynasty + 1] -= deposit
-
-    # if validator had already initialized logout remove his deposit
-    # from next dynasty rather than from his end_dynasty
-    if self.validators[validator_index_1].end_dynasty < self.default_end_dynasty:
-        self.dynasty_wei_delta[self.validators[validator_index_1].end_dynasty] += deposit
+    # if validator not logged out yet, remove total from next dynasty
+    end_dynasty: int128 = self.validators[validator_index_1].end_dynasty
+    if self.dynasty < end_dynasty:
+        deposit: decimal(wei/m) = self.validators[validator_index_1].deposit
+        self.dynasty_wei_delta[self.dynasty + 1] -= deposit
+
+        # if validator was already staged for logout at end_dynasty,
+        # ensure that we don't doubly remove from total
+        if end_dynasty < self.default_end_dynasty:
+            self.dynasty_wei_delta[end_dynasty] += deposit
 
     self.delete_validator(validator_index_1)
     send(msg.sender, slashing_bounty)

tests/conftest.py

@@ -306,6 +306,27 @@ def mk_suggested_vote(validator_index, privkey):
     return mk_suggested_vote
 
 
+@pytest.fixture
+def mk_slash_votes(casper, mk_vote, fake_hash):
+    def mk_slash_votes(validator_index, privkey):
+        vote_1 = mk_vote(
+            validator_index,
+            casper.recommended_target_hash(),
+            casper.current_epoch(),
+            casper.recommended_source_epoch(),
+            privkey
+        )
+        vote_2 = mk_vote(
+            validator_index,
+            fake_hash,
+            casper.current_epoch(),
+            casper.recommended_source_epoch(),
+            privkey
+        )
+        return vote_1, vote_2
+    return mk_slash_votes
+
+
 @pytest.fixture
 def mk_logout():
     def mk_logout(validator_index, epoch, key):

tests/test_slashing.py

@@ -66,3 +66,73 @@ def test_slash_no_surround(casper, funded_privkey, deposit_amount, new_epoch,
     assert casper.deposit_size(validator_index) == 0
     assert casper.dynasty_wei_delta(next_dynasty) == \
         (-deposit_amount / casper.deposit_scale_factor())
+
+
+def test_slash_after_logout_delay(casper, funded_privkey, deposit_amount, get_last_log,
+                                  induct_validator, mk_suggested_vote, mk_slash_votes,
+                                  new_epoch, fake_hash, logout_validator):
+    validator_index = induct_validator(funded_privkey, deposit_amount)
+    scaled_deposit_size = casper.validators__deposit(validator_index)
+
+    assert casper.total_curdyn_deposits_scaled() == deposit_amount
+
+    logout_validator(validator_index, funded_privkey)
+    end_dynasty = casper.validators__end_dynasty(validator_index)
+
+    assert casper.dynasty_wei_delta(end_dynasty) == -scaled_deposit_size
+
+    # step past validator's end_dynasty
+    dynasty_logout_delay = casper.dynasty_logout_delay()
+    for _ in range(dynasty_logout_delay + 1):
+        casper.vote(mk_suggested_vote(validator_index, funded_privkey))
+        new_epoch()
+
+    new_scaled_deposit_size = casper.validators__deposit(validator_index)
+    # should have a bit more from rewards
+    assert new_scaled_deposit_size > scaled_deposit_size
+
+    assert casper.dynasty() == casper.validators__end_dynasty(validator_index) + 1
+    assert casper.dynasty_wei_delta(casper.dynasty() + 1) == 0
+
+    vote_1, vote_2 = mk_slash_votes(validator_index, funded_privkey)
+    casper.slash(vote_1, vote_2)
+
+    assert casper.deposit_size(validator_index) == 0
+
+    # validator already out of current deposits. should not change dynasty_wei_delta
+    assert casper.dynasty_wei_delta(end_dynasty) == -new_scaled_deposit_size
+    assert casper.dynasty_wei_delta(casper.dynasty() + 1) == 0
+
+
+def test_slash_after_logout_before_logout_delay(casper, funded_privkey, deposit_amount,
+                                                get_last_log, induct_validator,
+                                                mk_suggested_vote, mk_slash_votes,
+                                                new_epoch, fake_hash, logout_validator):
+    validator_index = induct_validator(funded_privkey, deposit_amount)
+    scaled_deposit_size = casper.validators__deposit(validator_index)
+
+    assert casper.total_curdyn_deposits_scaled() == deposit_amount
+
+    logout_validator(validator_index, funded_privkey)
+    end_dynasty = casper.validators__end_dynasty(validator_index)
+
+    assert casper.dynasty_wei_delta(end_dynasty) == -scaled_deposit_size
+
+    # step forward but not up to end_dynasty
+    casper.vote(mk_suggested_vote(validator_index, funded_privkey))
+    new_epoch()
+
+    new_scaled_deposit_size = casper.validators__deposit(validator_index)
+
+    assert casper.dynasty() < end_dynasty - 1
+    assert casper.dynasty_wei_delta(casper.dynasty() + 1) == 0
+    assert casper.dynasty_wei_delta(end_dynasty) == -new_scaled_deposit_size
+
+    vote_1, vote_2 = mk_slash_votes(validator_index, funded_privkey)
+    casper.slash(vote_1, vote_2)
+
+    assert casper.deposit_size(validator_index) == 0
+
+    # remove deposit from next dynasty rather than end_dynasty
+    assert casper.dynasty_wei_delta(end_dynasty) == 0
+    assert casper.dynasty_wei_delta(casper.dynasty() + 1) == -new_scaled_deposit_size