EIP-689: Address Collision of Contract Address Causes Exceptional Halt


  Ethereum Improvement Proposals
        
        
          
            
              
            
          
        

        AllCoreNetworkingInterfaceERCMetaInformational

      



      
        
  
    

  
    
      🚧 Stagnant
    
    
    
    
    
      Standards Track: Core
    
  
  
    
      EIP-689: Address Collision of Contract Address Causes Exceptional Halt
    
    
      
        
      
    
    
      
        
      
    
  

  

  	Authors	Yoichi Hirai <i@yoichihirai.com>
	Created	2017-08-15


  


  

  
    Table of Contents

    	Simple Summary
	Abstract
	Motivation
	Specification
	Rationale
	Backwards Compatibility
	Test Cases
	Implementation
	Copyright



  


  
      
      
         Simple Summary
      
      
    


This EIP proposes to make contract creation fail on an account with nonempty code or non-zero nonce.

  
    
      
      
         Abstract
      
      
    


Some test cases in the consensus test suite try to deploy a contract at an address already with nonempty code. Although such cases can virtually never happen on the main network before the Constantinople fork block, the test cases detected discrepancies in clients’ behavior.  Currently, the Yellow Paper says that the contract creation starts with the empty code and the initial nonce even in the case of address collisions. To simplify the semantics, this EIP proposes that address collisions cause failures of contract creation.

  
    
      
      
         Motivation
      
      
    


This EIP has no practical relevance to the main net history, but simplifies testing and reasoning.


This EIP has no effects after Constantinople fork because EIP-86 contains the changes proposed in this EIP. Even before the Constantinople fork, this EIP has no practical relevance because the change is visible only in case of a hash collision of keccak256.


Regarding testing, this EIP relieves clients from supporting reversion of code overwriting.


Regarding reasoning, this EIP establishes an invariant that non-empty code is never modified.

  
    
      
      
         Specification
      
      
    


If block.number >= 0, when a contract creation is on an account with non-zero nonce or non-empty code, the creation fails as if init code execution resulted in an exceptional halt.  This applies to contract creation triggered by a contract creation transaction and by CREATE instruction.

  
    
      
      
         Rationale
      
      
    


It seems impractical to implement never-used features just for passing tests.  Client implementations will be simpler with this EIP.

  
    
      
      
         Backwards Compatibility
      
      
    


This EIP is backwards compatible on the main network.

  
    
      
      
         Test Cases
      
      
    


At least the BlockchainTest called createJS\_ExampleContract\_d0g0v0\_EIP158 will distinguish clients that implement this EIP.

  
    
      
      
         Implementation
      
      
    

  
    
      
      
         Copyright
      
      
    

Copyright and related rights waived via CC0.


  Citation

  Please cite this document as:

  
  Yoichi Hirai <i@yoichihirai.com>, "EIP-689: Address Collision of Contract Address Causes Exceptional Halt [DRAFT]," Ethereum Improvement Proposals, no. 689, August 2017. [Online serial]. Available: https://eips.ethereum.org/EIPS/eip-689.






      
    
  

  

    Ethereum Improvement Proposals


    
      
        	Ethereum Improvement Proposals


      


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        Ethereum Improvement Proposals (EIPs) describe standards for the Ethereum platform, including core protocol specifications, client APIs, and contract standards.