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Unwrap DelegatingBytes32 and prevent Hash from wrapping other Hash instances #1423
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rain-on
reviewed
May 9, 2019
| Bytes32 wrapped = v; | ||
|
|
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| if (wrapped instanceof DelegatingBytes32) { | ||
| wrapped = ((DelegatingBytes32) wrapped).wrapped; |
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just return the thing - then at the bottom return v.
rain-on
approved these changes
May 9, 2019
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PR description
When blocks are generated without any change to the world state (only possible with empty blocks in Clique or IBFT where there's no block reward), the world state root hash was being repeatedly wrapped in a new
Hashinstance until eventually it triggered a stack overflow. The sameHashinstance survives because the actualBlockHeaderinstance is cached by the blockchain and the state root hash round trips through the block creator, world state Merkle trie entirely unchanged except for being wrapped an additional time.Fix is to apply the same
unwrapprocess toDelegatingBytes32as already existed inDelegatingBytesValue. To save creating a new object at all a check has also been added toHash.wrapso that it just casts the existing value if it's already aHash.