test: add test checking that inputs can not be exited from restarted ife after outputs finalized on processing the first ife

plasma_framework/python_tests/tests/contracts/root_chain/test_process_exits.py

@@ -1002,3 +1002,63 @@ def test_challenged_standard_exit_does_not_block_ife_output_exit(testlang, plasm
     # and does not get the tokens back
     alice_token_balance = token.balanceOf(alice.address)
     assert alice_token_balance == alice_token_balance_before
+
+
+def test_after_canonical_ife_is_finalized_inputs_are_not_exited_when_ife_is_restarted_and_non_canonical(testlang, plasma_framework, token):
+    """
+    1. Alice and Bob send a canonical transaction transfering their funds to Alice.
+    2. Alice starts an in-flight exit and exits her output.
+    3. Bob creates a competing transaction spending his input.
+    4. In-flight exit is restarted and is non-canonical as Bob produces a comepeting transaction.
+    5. Alice and Bob piggyback on their inputs and exit is processed.
+    6. Funds from inputs are not withdrawn as they were marked as finalized when Alice exited her output in step 2.
+    """
+    alice, bob, deposit_amount = testlang.accounts[0], testlang.accounts[1], 100
+    alice_deposit_id = testlang.deposit(alice, deposit_amount)
+    bob_deposit_id = testlang.deposit(bob, deposit_amount)
+    alice_output_amount = 2 * deposit_amount
+
+    spend_id = testlang.spend_utxo([alice_deposit_id, bob_deposit_id], [alice, bob], [(alice.address, NULL_ADDRESS, alice_output_amount)])
+
+    alice_eth_balance_before = testlang.get_balance(alice)
+
+    # transaction is not included in child chain and canonical in-flight exit is started and processed
+    testlang.start_in_flight_exit(spend_id)
+    testlang.piggyback_in_flight_exit_output(spend_id, 0, alice)
+    testlang.forward_timestamp(2 * MIN_EXIT_PERIOD + 1)
+    testlang.process_exits(NULL_ADDRESS, 0, 1)
+
+    # alice exits with her Eth output
+    alice_eth_balance = testlang.get_balance(alice)
+    assert alice_eth_balance == alice_eth_balance_before + alice_output_amount
+
+    # bob spends his inputs in a competing transaction
+    competing_spend_id = testlang.spend_utxo(
+        [bob_deposit_id], [bob], [(bob.address, NULL_ADDRESS, deposit_amount)],
+        force_invalid=True
+    )
+
+    # in-flight exit is restarted
+    testlang.start_in_flight_exit(spend_id)
+
+    # it's canonicity is challenged with the competing transaction
+    testlang.challenge_in_flight_exit_not_canonical(spend_id, competing_spend_id, account=bob)
+
+    # in-flight exit is not canonical
+    in_flight_exit = testlang.get_in_flight_exit(spend_id)
+    assert not in_flight_exit.is_canonical
+
+    # owners piggyback on inputs
+    testlang.piggyback_in_flight_exit_input(spend_id, 0, alice)
+    testlang.piggyback_in_flight_exit_input(spend_id, 1, bob)
+
+    eth_balance_before_processing_exits = testlang.get_balance(plasma_framework.eth_vault)
+
+    # exit is processed
+    testlang.forward_timestamp(2 * MIN_EXIT_PERIOD + 1)
+    testlang.process_exits(NULL_ADDRESS, 0, 2)
+
+    # users didn't exit their inputs - no funds were withdrawn from the eth vault
+    # because in-flight transaction output is already exited and the inputs were flagged as finalized
+    eth_balance = testlang.get_balance(plasma_framework.eth_vault)
+    assert eth_balance_before_processing_exits == eth_balance