fix(protocol): fix tid in getTransitionByParentHash (#18895)

Co-authored-by: xiaodino <[email protected]>
taikoxyz · Feb 10, 2025 · 0071fcb · 0071fcb
1 parent 30428c2
commit 0071fcb
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Showing 2 changed files with 20 additions and 2 deletions.
diff --git a/packages/protocol/contracts/layer1/based/TaikoInbox.sol b/packages/protocol/contracts/layer1/based/TaikoInbox.sol
@@ -445,7 +445,20 @@ abstract contract TaikoInbox is EssentialContract, ITaikoInbox, ITaiko {
         Batch storage batch = state.batches[slot];
         require(batch.batchId == _batchId, BatchNotFound());
 
-        uint24 tid = state.transitionIds[_batchId][_parentHash];
+        uint24 tid;
+        if (batch.nextTransitionId > 1) {
+            // This batch has at least one transition.
+            if (state.transitions[slot][1].parentHash == _parentHash) {
+                // Overwrite the first transition.
+                tid = 1;
+            } else if (batch.nextTransitionId > 2) {
+                // Retrieve the transition ID using the parent hash from the mapping. If the ID
+                // is 0, it indicates a new transition; otherwise, it's an overwrite of an
+                // existing transition.
+                tid = state.transitionIds[_batchId][_parentHash];
+            }
+        }
+
         require(tid != 0 && tid < batch.nextTransitionId, TransitionNotFound());
         return state.transitions[slot][tid];
     }

diff --git a/packages/protocol/test/layer1/based/InboxTest_ProposeAndProve.t.sol b/packages/protocol/test/layer1/based/InboxTest_ProposeAndProve.t.sol
@@ -237,7 +237,12 @@ contract InboxTest_ProposeAndProve is InboxTestBase {
         assertEq(ts.stateRoot, bytes32(uint256(0)));
 
         vm.expectRevert(ITaikoInbox.TransitionNotFound.selector);
-        ts = inbox.getTransitionByParentHash(9, ts.parentHash);
+        ts = inbox.getTransitionByParentHash(9, correctBlockhash(9));
+
+        ts = inbox.getTransitionByParentHash(9, correctBlockhash(8));
+        assertEq(ts.parentHash, correctBlockhash(8));
+        assertEq(ts.blockHash, correctBlockhash(9));
+        assertEq(ts.stateRoot, bytes32(uint256(0)));
 
         (batchId, blockId, ts) = inbox.getLastSyncedTransition();
         assertEq(batchId, 5);