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"retrieved ancestor invalid" message during synchronization

We have been running a private ethereum network for a couple of months. Today we tried to add a new node to the network. When the node was synchronizing, (after 3-4 hours) it stopped with the following message : 5a0e number=847268 hash=0000...0000…
user813
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What is the target block time for Casper?

With PoW, the block time is around 17 seconds. What is the target block time for Casper's PoS?
Randomblue
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Are Transactions originating from one account mined in nonce order?

Discussion in another thread raises an interesting point. how many transactions could be included in a new block from the same account? Since miners can opt to omit a known transaction from the block they're working on miners don't have…
Rob Hitchens
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How to calculate the location index (slot) in storage of a mapping key

I read the documentation and tried some other approaches but it's not working for me. I'm not sure what I'm missing. Let's say I have a contract with a mapping and I would like to know the storage slot location for a particular key and be able to…
Jeremy Then
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solidity 0.4.10 require vs throw

In this trivial example, both require and throw perform the same guard. And according to remix using the 0.4.10 compiler, both functions, when presented with a value <= 10 throw : VM Exception: invalid opcode. Other than maybe the readability of…
dbryson
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MetaMask - RPC Error: The requested account and/or method has not been authorized by the user

I'm following the tutorial on https://www.toptal.com/ethereum/one-click-login-flows-a-metamask-tutorial#how-the-login-flow-works. One of the sections show an example of prompting the user's Metamask to sign a piece of data using the following in the…
Stephen Fong
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How to build a front end for dApp

I am studying about DApps and Ethereum. I did get the Solidity part but I am confused about the front-end apps. Is it possible that I use web framework like PHP Laravel/Rails for Frontend/Db operations and interact with backend Blockchain via…
Volatil3
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Find the creator of a contract

I want to prove that a contract was deployed by a specific address (a factory contract). I have noticed that block explorers such as https://etherscan.io/ list the contract creator. How do they get this information? I cant find any way of getting a…
Joe
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from solidity: TypeError: Member "log" not found or not visible after argument-dependent lookup in type(library console)

from solidity: TypeError: Member "log" not found or not visible after argument-dependent lookup in type(library console). Im using hardhats lib "hardhat/console.sol"; I want to console.log the mapping and its members also, How can I do that ? //…
Syed Murtaza Ali Shah
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Need help to break down large contract

related to question Best practices to solve the problem of a contract that is too large?, I am facing similar issue (contract too large to be deployed, compare to gasLimit of the blockchain) and before I launch a refactoring of my code I am seeking…
Guenole de Cadoudal
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Getting an address from ethereumjs-utils ecrecover

I am trying to sign a string using web3.eth.sign() and then get the public key I signed with from the signature. To do this I am using ecrecover() from ethereumjs-utils, which returns a buffer. When I use bufferToHex() on the buffer it gives a hex…
Joe
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Invalid array length, expected integer literal

I'm trying to declare an in-memory array with a fixed length: uint length = 10; uint[length] memory priorityList; However, it just displays this error message: Invalid array length, expected integer literal Do I have to do uint[10] memory…
johnhckuo
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Truffle Dapp only works when I first use `truffle migrate --reset`

When I first load my Dapp with testrpc the functionality doesn't work until I use the command truffle migrate --reset Any ideas why?
ethereal
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Unable to define greeterContract in the Greeter tutorial. Breaking change in Solidity 0.4.9!

I was following the Greeter tutorial on Go Ethereum wiki and got stuck on the "var greeterContract = web3.eth.contract(greeterCompiled.greeter.info.abiDefinition)" phase returning TypeError: Cannot access member 'info' of undefined. I have solC…
Henrik
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Programmatically saving the contract address of a submitted contract

I understand how the below web3js code block works, adapted from here: https://github.com/ethereum/wiki/wiki/JavaScript-API#web3ethcontract But how does one save the contract address programmatically? One could, I suppose, open a file and persist…
NYCeyes
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