
Ethereum represents the gateway to a worldwide, decentralized computing paradigm. This platform enables you to run decentralized applications (DApps) and smart contracts that have no central points of failure or control, integrate with a payment network, and operate on an open blockchain. With this practical guide, Andreas M. Antonopoulos and Gavin Wood provide everything you need to know about building smart contracts and DApps on Ethereum and other virtual-machine blockchains.

Discover why IBM, Microsoft, NASDAQ, and hundreds of other organizations are experimenting with Ethereum. This essential guide shows you how to develop the skills necessary to be an innovator in this growing and exciting new industry.

A guide to the operation and use of Ethereum and other EVM-compatible blockchains.

Mastering Ethereum


The story of the idealists, technologists, and opportunists fighting to bring cryptocurrency to the masses.

In their short history, Bitcoin and other cryptocurrencies have gone through booms, busts, and internecine wars, recently reaching a market valuation of more than $2 trillion. The central promise of crypto endures—vast fortunes made from decentralized networks not controlled by any single entity and not yet regulated by many governments.

The recent growth of crypto would have been all but impossible if not for a brilliant young man named Vitalik Buterin and his creation: Ethereum. In this book, Laura Shin takes readers inside the founding of this novel cryptocurrency network, which enabled users to launch their own new coins, thus creating a new crypto fever. She introduces readers to larger-than-life characters like Buterin, the Web3 wunderkind; his short-lived CEO, Charles Hoskinson; and Joe Lubin, a former Goldman Sachs VP who became one of crypto’s most well-known billionaires. Sparks fly as these outsized personalities fight for their piece of a seemingly limitless new business opportunity.

This fascinating book shows the crypto market for what it really is: a deeply personal struggle to influence the coming revolution in money, culture, and power.

Idealism, Greed, Lies, and the Making of the First Big Cryptocurrency Craze

The Cryptopians


Tokens - often referred to as cryptocurrencies - can represent anything from an asset to an access right, such as gold, diamonds, a fraction of a Picasso painting or an entry ticket to a concert. Tokens could also be used to reward social media contributions, incentivize the reduction of CO2 emissions, or even ones attention for watching an ad. While it has become easy to create a token, which is collectively managed by a public Web3 infrastructure like a blockchain network, the understanding of how to apply these tokens is still vague.

The industry keeps referring to “Blockchain” as different from “Bitcoin,” creating an artificial divide that is often misleading. There seems to be too little understanding about the fact that Bitcoin is a blockchain network, which is (a) globally managed by people who mostly do not know each other, and (b) enabled by the consensus protocol that (c) incentivizes all network actors for their contributions with a native token. The governance rules are tied to the minting of a native blockchain token. The Bitcoin token can, therefore, be seen as the currency of a distributed Internet tribe, called the Bitcoin network, where network actors are rewarded with Bitcoins, just as the Ether is the currency of the distributed Internet tribe Ethereum network, or Sia is the native currency of the Sia network. The Bitcoin network and other distributed ledgers all represent a collectively maintained public infrastructure and are the backbone of the next generation Internet, what the crypto community refers to as the Web3.

This book attempts to summarize existing knowledge about blockchain networks and other distributed ledgers as the backbone of the Web3, and contextualize the socio-economic implications of the Web3 applications such as smart contracts, tokens, and DAOs to the concepts of money, economics, governance and decentralized finance (DeFi).

Token Economy


Learn to Code Blockchain DApps By Building Simple Games

CryptoZombies is an interactive school that teaches you all things technical about blockchains. Learn to make smart contracts in Solidity or Libra by making your own crypto-collectibles game.

#1 Solidity Tutorial & Ethereum Blockchain Programming Course

CryptoZombies


More and more DeFi projects on Ethereum are getting hacked. This is your chance to join the party.

Each challenge can be considered standalone. Depending on the challenge, you should either stop the system from working, steal as much funds as you can, or do some other unexpected things.

Put your black hat on, and break some DeFi projects on Ethereum!

Damn Vulnerable DeFi


This is an interactive tutorial website for learning Vyper while building games using smart contracts, similar to Cryptozombies.

VyperFun


Blockchain is an exciting new discipline in Computer Science. It combines a wide array of skills from math and cryptography to social sciences and understanding organizations. Understanding blockchain decentralization and how/where to apply it is a brand new skill that very few have mastered.

You will build your skills from the ground up with strong fundamentals that will provide you with the ability to adapt in this rapidly evolving ecosystem.

Choose From Multiple Paths to Begin Your Ethereum Coding Journey.

Fast-track your Ethereum Developer career in an instructor-led and challenging bootcamp focused on discussion and application!

ChainShot


This is an initiative for the early solidity developers by those who were early developers sometime.

In this approach, we are looking to categorize the smart contract according to the difficulty level in multiple standards. For now, we are keeping the standard 0 to 5(can be discussed).

This initiative needs great support from Blockchain enthusiast, developer and researchers to build this school in a way which can attract learners and provide them ease for development.

First place for early developers to learn Solidity 

solidity-school


## Introductory Modules

- What is a SNARK?
- Building a SNARK (part 1)
- Building a SNARK (part 2)

## Whiteboard Sessions with ZK Projects​

- SNARKs vs. STARKS with Brendan and Bobbin
- PLONK and Custom Gates with Adrian Hamelink
- Lookup Arguments for Performance Optimisation with Mary Maller
- Zero Knowledge Virtual Machine (zkVM) with grjte
- Achieving Decentralised Private Computation with Pratyush Mishra
- Introduction to zkRollups with Barry Whitehat
- zkEVM with Jordi Baylina
- ZK Swaps with Henry de Valence
- zkID with Oleksandr Brezhniev
- Fast Recursion with Plonky2 with William Borgeaud

ZK Whiteboard Sessions is an educational series on all things zero knowledge

ZK Whiteboard Sessions


## What is a smart contract?

Smart contracts are the backbone of decentralized applications (DApps) and Web3. A smart contract is a simple program that lives on a blockchain network (such as Ethereum). They're actually not that smart. And nothing like a (legal) contract. They’re more like an executable piece of code that requires input or an trigger from an external source. They can validate those input conditions and if correct, execute their own logic to update the state on a blockchain.

## Benefits

They often serve the following purposes:
- Store and maintain data
- Manage relationships with users, or other contracts

Benefits of smart contracts are
- Immutable - once deployed none can change them
- Composable - they’re public and anyone can interact with them, or build on top of them. Much like public APIs

## Resources

The following resources have been the most popular resources on the site for a long time. These are all highly recommend to start learning about Solidity


### 1. Official Solidity website
The most obvious resources is ofcourse the official website and documentation of the Solidity team itself. The Solidity team covers all the core concepts and fundamentals of Solidity and smart contracts in general. Highly recommended

https://soliditylang.org/


### 2. Solidity by Example
The second one on the list is Solidity by Example. A great collection of more pratical examples, incl. source code and supporting videos.

https://solidity-by-example.org/


### 3. CryptoZombies 
CryptoZombies is an interactive school that teaches you all things technical about blockchains. A fun and interactive way to write smart contracts in Solidity by making your own crypto-collectibles game.

https://cryptozombies.io/


### 4. Speedrun Ethereum

Speedrun Ethereum helps you get to the next level. It teaches you how to build on Ethereum; the superpowers and the gotchas while you build up your Web3 portfolio. If you like this, also make sure to check out the other work of the amazing [Austin Griffith](https://twitter.com/austingriffith) such as [ETH-build](https://eth.build/) and [Scaffold-eth](https://scaffoldeth.io/).

https://speedrunethereum.com/


### 5. Smart Contract Best Practices 

Smart contracts are complex instruments that have the authority to allocate high-value resources between complex systems. Often working autonomously. With huge financial loss at risk. This makes them critical components in these systems. Development of such components requires thoughtful design, solid engineering practices, rigorous testing and a strong security mindset. This document provides a baseline knowledge of security considerations.

https://consensys.github.io/smart-contract-best-practices/


## Other resources

If you'd like to read more, make sure to checkout all the other [Solidity](/tags/smart%20contracts) resources on the site.

Solidity is a programming language designed for developing smart contracts that run on Ethereum. It's the most in demand skill in the Web3 space. These are the best resources to help you learn more about it.

Best resources to learn Solidity


This handbook is for people who are interested in exploring the vision behind “Web3”, and who wish to acquire in-demand skills that are essential to realizing that vision.  

A Handbook for Smart Contract Development

Learn Solidity

Free resources to learn about Zero Knowledge Proofs (ZKPs) and Cryptography

Road to ZK


Create Eth App supports multiple frontend frameworks. It comes with a host of decentralized finance templates pre-filled with contract ABIs, addresses and subgraphs. Everything you need to build a modern Ethereum-powered single-page app.

- Learning how to write Ethereum-powered apps in a comfortable and feature-rich development environment.
- Starting new Ethereum-powered single-page React applications without wasting time on copy-pasting boilerplates
- Creating examples with React for your Ethereum-related libraries and components.

Create Ethereum-powered apps with one command

Create Eth App


**Features**
- Next.js
- Ethereum
- Typescript
- Chakra UI
- Wagmi
- Connectkit
- Ethers.js

An open-source Next.js + Ethereum starter kit to quickly ship Web3 Apps

Nexth Starter kit


Everything you need to build on Ethereum!

Quickly experiment with Solidity using a frontend that adapts to your smart contract

Forkable Ethereum dev stack focused on fast product iterations

Scaffold-ETH


Becoming a blockchain engineer is the most fun, rewarding, and exhilarating choice I’ve and my colleagues have ever made. And we’ve already blazed the trail for you to get started! In this article, we will show you exactly how to learn to become a blockchain engineer, from beginner to professional.

Spoiler alert, here is the exact blueprint we are going to cover to get you to a successful blockchain engineer:

1. Understand why you should become a blockchain engineer
2. Take a Blockchain Course
3. Join a Hackathon, the Community, & Build
4. Start your own protocol, Take a job, Freelance & Contribute

If you make it this far, you’ve done it! Although, I’ll add a bonus step 5 that we will talk about soon.

5. You’ve made it! Keep learning!

That’s it! These are the exact steps you need to take to become a blockchain engineer!

Become a blockchain, solidity, and smart contract engineer by following these steps

Become a Blockchain Engineer


Odds are you’ve heard about the Ethereum blockchain, whether or not you know what it is. It’s been in the news a lot lately, including the cover of some major magazines, but reading those articles can be like gibberish if you don’t have a foundation for what exactly Ethereum is. So what is it? In essence, a public database that keeps a permanent record of digital transactions. Importantly, this database doesn’t require any central authority to maintain and secure it. Instead it operates as a “trustless” transactional system — a framework in which individuals can make peer-to-peer transactions without needing to trust a third party OR one another.

Still confused? That’s where this post comes in. My aim is to explain how Ethereum functions at a technical level, without complex math or scary-looking formulas. Even if you’re not a programmer, I hope you’ll walk away with at least better grasp of the tech. If some parts are too technical and difficult to grok, that’s totally fine! There’s really no need to understand every little detail. I recommend just focusing on understanding things at a broad level.

Many of the topics covered in this post are a breakdown of the concepts discussed in the yellow paper. I’ve added my own explanations and diagrams to make understanding Ethereum easier. Those brave enough to take on the technical challenge can also read the Ethereum yellow paper.

Many of the topics covered in this post are a breakdown of the concepts discussed in the yellow paper. I’ve added my own explanations and diagrams to make it easier.

How does Ethereum work, anyway?


I recently joined Edge & Node as a Developer Relations Engineer and have been diving deeper into smart contract development with Ethereum. I have settled upon what I think is the best stack for building full stack dApps with Solidity:

▶︎ Client Framework - React
▶︎ Ethereum development environment - Hardhat
▶︎ Ethereum Web Client Library - Ethers.js
▶︎ API layer - The Graph Protocol

Building Full Stack dApps with React, Ethers.js, Solidity, and Hardhat

The Complete Guide to Full Stack Ethereum Development


Educational sandbox for building on web3. Visually understand how Ethereum works by doing.

ETH.Build


https://www.youtube.com/watch?v=gyMwXuJrbJQ

This course will give you a full introduction into all of the core concepts in blockchain, smart contracts, solidity, NFTs/ERC721s, ERC20s, Coding Decentralized Finance (DeFi), javascript and solidity, Chainlink, Ethereum, upgradable smart contracts, and full stack blockchain development.   

Some of the technologies covered are:
- The Graph
- Chainlink
- Metamask
- Alchemy
- Remix
- Hardhat
- Solidity
- Openzeppelin
- Trail of Bits
- Ganache
- Ethers
- Etherscan
- Coinmarketcap
- Aave
- IPFS
- Fleek.hq
- Filecoin
- NextJS
- Moralis
- Web3uikit
- Opensea
- Pinata
- Nft.storage

 And more!

Follow along with the videos and you'll be a blockchain wizard in no time!  💻 The repository with helpful links to all code, resources, and support forums is located here: https://github.com/smartcontractkit/full-blockchain-solidity-course-js.

This course will give you a full introduction into all of the core concepts related to blockchain, smart contracts, Solidity, ERC20s, full-stack Web3 dapps, decentralized finance (DeFi), JavaScript, TypeScript, Chainlink, Ethereum, upgradable smart contracts, DAOs, the graph, moralis, aave, IPFS, and more. Follow along with the videos and you'll be a blockchain wizard in no time!

Learn Blockchain, Solidity, and Full Stack Web3 Development with JavaScript – 32-Hour Course


Learning Solidity with a collection of YouTube videos and example code.

Learning Solidity


Here we collect and discuss the best DeFi & Blockchain researches and tools 

DeFi Developer roadmap


Nowadays there are countless well-made resources on how to learn blockchain development of all kinds and with different specializations in mind, however, it is still very hard to get guidance and personalized suggestions based on your interests. I am writing this guide in order to provide an aggregator of all the resources that I’ve found over the years, plus give some opinionated commentary on how to approach them and how to use them in order to maximize learning and practical understanding in order to get building cool things in the space as soon as possible.

This guide will focus on the Ethereum ecosystem as that’s where most developers and applications are. If you are interested in other ecosystems that are non-EVM compatible and are not L2s on Ethereum, then check out their respective documentation or guides written by their developer communities. Examples of other non-EVM compatible blockchains that are popular are Solana (Rust/Anchor), Polkadot (Rust/Substrate), Cosmos, Terra, and others. Most of these blockchains do or will support the EVM stack through various initiatives like Neon EVM (Solana), Moonbeam/Moonriver (Polkadot/Kusama), EVMOS (Cosmos), etc.

I really want this guide to become a community-sourced public good that everyone will be able to take advantage of. I will do my best to present it to the wider blockchain developer community to get constructive feedback, proofreading help, and insight into how to make it the best available guide available.

devpill.me


This document provides a baseline knowledge of security considerations for intermediate Solidity programmers. It is maintained by ConsenSys Diligence, with contributions from our friends in the broader Ethereum community.

A guide to Ethereum smart contract security best practices

Smart Contract Best Practices

## Description

We've started using build caches for the local-testnet job, which seems to be a good testing ground before we apply caches more broadly.

Currently there's an issue where the cache can be transferred from a machine with ADX to a machine without, causing a SIGILL (exit code 132): https://github.com/sigp/lighthouse/runs/5545911178?check_suite_focus=true

I think we should update the cache key so that it includes the machine's ADX status. That way there won't be any cache sharing between machines with ADX and without. Although many hypervisors lie about ADX compatibility in their CPUID it's sufficient for us to rely on the CPUID as that's what the BLST library uses to enable/disable ADX (see: https://github.com/supranational/blst/blob/f2380d22a1c6a5f82c1bc187ec7fd4019051969e/bindings/rust/build.rs#L102-L109).


good first issue

infra-ci

lighthouse

Rust

Handle BLS portable vs modern distinction in CI cache

## Description

I am getting an error with no indication of which line it refers to:
```
UnimplementedFeatureError: Copying of type struct MyStruct memory[] memory to storage not yet supported.
```

## Environment

- Compiler version: 0.8.12

## Steps to Reproduce

Well, I need to dig through my code in order to find it, but on the compiler side, the problem is probably in ArrayUtils.cpp:
```
solUnimplemented("Copying of type " + _sourceType.toString(false) + " to storage not yet supported.");
```

Thanks :)

bug :bug:

medium difficulty

should report better error

low effort

medium impact

should have

Solidity, the Smart Contract Programming Language

solidity

`UnimplementedFeatureError` with no line indication when copying an array of structs to storage

Closes #11889.

**## Abstract**

Private functions are isolated to the specific contract they are defined in. This holds true during inheritance as well. A contract that inherits another contract cannot use or access private functions from the parent contract. In cases where a contract inherits two separate contracts that each contain the same private function name, there should be no compilation error due to naming conflicts. 

**## Motivation**

Because inheriting contracts cannot use or access the private functions of parent contracts, enforcing uniqueness of these private function names is unnecessarily restrictive.

An example of how this can happen is explained [here](https://github.com/ethereum/solidity/issues/11889#issue-987605750)


**## Specification**

1. Update the [ambiguous overrides checking function](https://github.com/ethereum/solidity/blob/c47da51eab8e5c4ebff0f6dd2ca748179aa21ab4/libsolidity/analysis/OverrideChecker.cpp#L727) in [OverrideChecker](https://github.com/ethereum/solidity/blob/c47da51eab8e5c4ebff0f6dd2ca748179aa21ab4/libsolidity/analysis/OverrideChecker.cpp#L1) to track the scope of functions when comparing them for uniqueness.

2.  Write tests for that case [here](https://github.com/ethereum/solidity/tree/69411436139acf5dbcfc5828446f18b9fcfee32c/test/libsolidity/syntaxTests/inheritance)  


**## Backwards Compatibility**

This change makes solidity compilation strictly more permissive and should not introduce any incompatibilities with existing contracts.

help wanted

language design :rage4:

bounty worthy :moneybag:

low impact

nice to have

Private function names should not be checked for uniqueness when inherited by other contracts

**The scope of this issue reduced substantially, see https://github.com/foundry-rs/foundry/issues/883#issuecomment-1172638818**

### Component

Forge

### Describe the feature you would like

I would expect forge install/remove command to automatically update `remapping.txt` if present and also `foundry.toml` if inside the configuration file I've declared the remapping.

### Additional context

_No response_

T-feature

C-forge

P-low

D-easy

Cmd-forge-pm

Foundry is a blazing fast, portable and modular toolkit for Ethereum application development written in Rust.

foundry

forge install/remove should automatically update remappings.txt and foundry.toml

# 💎 Issue


### Description

Currently a lot of our tests utilize the `time` package and  its related objects such as `ticker`. We use timing based checks extensively in a lot of our tests, unfortunately the improper usage of them has led to many flaky tests. If the current time is withing the boundary of a second, this can lead to inconsistent results. The reason for this is that certain checks/conditions are triggered once the current unix cutoff time increases by 1 second. This holds true for any usage of `time.Now()` along with `time.Ticker()` .  

Some tests that fail due to this:
`TestWaitForSlotTwoThird_WaitCorrectly` 
`TestStreamDuties_OK`
`TestStreamDuties_OK_ChainReorg`

The solution would be to refactor tests so that the execution of these tests will not be affected by whatever the current time is. 

cc @maxkaneco

Help Wanted

Go implementation of Ethereum proof of stake

prysm

Improper Usage Of Time And Tickers in Tests

We have made the switch everywhere except for React components and we should get to a point where we are consistent across the codebase.

For Example: [`interface Props` should be changed to `type Props = `](https://github.com/tallycash/extension/blob/main/ui/components/Shared/SharedFeeSelectButton.tsx#L4)

Type: Plumbing

Tally Ho, the community owned and operated Web3 wallet.

extension

TypeScript

Consistently use `type` instead of `interface` across the codebase.

# 💎 Issue

### Background
Prysm uses 2 flags to help identify where to store certain cached items ( such as valdiator.db,auth-token, terms of service acceptance, etc). the user experience is not very clear when to use one or the other and should be looked into how to safely manage or document for the future.

### Description
current state of things 
- If a walletdir is provided then it will be used to store the validator db
- if a datadir is provided it will override the walletdir location, but only if it's a different path from the default datadir path
- Terms of Service acceptance file ( file required to skip user prompt  for agreements) only uses the datadir path instead of a provided walletdir path
- walletdir also sets the root for the keymanager type path

Priority: Low

Tracking

Cleanup

Improving --walletdir vs --datadir flag UX

**Is your feature request related to a problem? Please describe.**
Slashers are the police of the beacon chain. Why not add support for creating slashers nodes with Sedge?

on-premise

A one-click setup tool for PoS network/chain validators and nodes.

sedge

Support slashers

Using 2.2.3LTS using the contract-api I have this method

```
   @Transaction(submit=false)
    public QueryResponse<String> paginatedRichQuery(Context ctx, String queryString, String pagesize, String passedBookmark) {
        logger.debug("Entering paginatedRichQuery with pagesize [" + pagesize + "] and query string: " + queryString);
        int pageSize = Integer.parseInt(pagesize);

        final QueryResultsIteratorWithMetadata<KeyValue> iterator = ctx.getStub().getQueryResultWithPagination(queryString, pageSize, passedBookmark);
        QueryResponseMetadata metadata = iterator.getMetadata();
        ArrayList<String> results = this.getAllResults(iterator);

        QueryResponse<String> response = new QueryResponse<String>(results.toArray(new String[results.size()]), new ResponseMetadata(metadata));
        logger.debug("Exiting paginatedRichQuery with response: " + response.toString());
        return response;
    }
```

QueryResponse is defined as follows

```
public class QueryResponse<T> {
    private T[] results;

    private ResponseMetadata responseMetadata;

    public QueryResponse(T[] results, ResponseMetadata responseMetadata) {
        this.results = results;
        this.responseMetadata = responseMetadata;
    }

    public T[] getResults() {
        return results;
    }

    public void setResults(T[] results) {
        this.results = results;
    }

    public ResponseMetadata getResponseMetadata() {
        return responseMetadata;
    }

    public void setResponseMetadata(ResponseMetadata responseMetadata) {
        this.responseMetadata = responseMetadata;
    }

}
```

When I invoke the transaction it fails due to trying because of the return value with

```
Thread[fabric-txinvoke:5,5,main] 12:04:38:330 INFO    org.hyperledger.fabric.contract.ContractRouter processRequest                    Got routing:paginatedRichQuery:org.example.FixedAssetContract
Thread[fabric-txinvoke:5,5,main] 12:04:38:345 SEVERE  org.hyperledger.fabric.Logger error                                              nulljava.lang.NullPointerException
        at org.hyperledger.fabric.contract.execution.JSONTransactionSerializer.toBuffer(JSONTransactionSerializer.java:84)
        at org.hyperledger.fabric.contract.execution.impl.ContractExecutionService.convertReturn(ContractExecutionService.java:89)
        at org.hyperledger.fabric.contract.execution.impl.ContractExecutionService.executeRequest(ContractExecutionService.java:67)
        at org.hyperledger.fabric.contract.ContractRouter.processRequest(ContractRouter.java:119)
        at org.hyperledger.fabric.contract.ContractRouter.invoke(ContractRouter.java:130)
        at org.hyperledger.fabric.shim.impl.ChaincodeInvocationTask.call(ChaincodeInvocationTask.java:100)
        at org.hyperledger.fabric.shim.impl.InvocationTaskManager.lambda$newTask$17(InvocationTaskManager.java:265)
        at java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1736)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
        at java.base/java.lang.Thread.run(Thread.java:834)
```

hacktoberfest

Hyperledger Fabric Contract and Chaincode implementation for Java https://wiki.hyperledger.org/display/fabric

fabric-chaincode-java

Java

NullPointerException trying to handle an unannotated return type via contract-api

Currently, this repo uses a fork of Unicorn made by @geohot  https://github.com/geohot/unicorn.git

George said he made a few fixes to it, which do have to upstream and/or merged upstream before we can switch over, so we should track, push for the fixes to be merged and switch when we can.

Quick search releaved the following issue: https://github.com/unicorn-engine/unicorn/issues/1470 but that seem to be fixed, but there seems to be more than that here: https://github.com/geohot/unicorn/commits/master

@geohot Could you comment as to what we need?

enhancement

On chain interactive fault prover for Ethereum

cannon

Solidity

Use upstream Unicorn

Both `gauntlet-solana/package.json` and `gauntlet-solana-contracts/package.json` contain a lint command that refers to `tsc`. The recommendation is that `eslint` be used to lint JavaScript or TypeScript projects.

gauntlet

chainlink-solana

Add eslint support

Both `gauntlet-terra/package.json` and `gauntlet-terra-contracts/package.json` contain a lint command that refers to `tsc`. The recommendation is that `eslint` be used to lint JavaScript or TypeScript projects.

chainlink-terra

Neither `gauntlet-solana` nor `gauntlet-solana-contracts` give a minimum required Node.js version. The recommendation is that a minimum required Node.js version be given for any JavaScript or TypeScript project that uses Node.js.

Explicitly declare minimum required Node.js version for any project that uses Node.js.

## Description

Users have reported the validator client being unable to start after running out of disk space due to the `api-token.txt` or `validator_key_cache.json` file being truncated/empty. I think this is a variant of an old issue that affected the validator definitions file, and was fixed by using atomic writes: https://github.com/sigp/lighthouse/issues/2159

Strangely, we already seem to be using atomic writes for the key cache, so this new issue may require something beyond that :thinking:. The user who reported it was running under Docker, and it's possible our current atomic write function doesn't work on Docker's volumes for some reason (do they behave like network drives?). 

## Steps to resolve

Ensure that `api-token.txt` and `validator_key_cache.json` are written using atomic writes (`write_file_via_temporary`).

Additionally, we could just delete and regenerate both files if they are found to be invalid, logging a warning if this occurs.


Fix handling of `api-token.txt` and `validator_key_cache.json` when disk is full

We currently support LLVM 9, 10, and 11. We should consider dropping one or two of those and supporting LLVM 12 and 13. 

I took a quick stab at this in #15, but gave up since it wasn't as simple as a few API changes.

Rewrite C++ code to automatically apply `constexpr` where possible

constexpr-everything

Support newer LLVM versions

### Which Caliper version are you using?

v0.4.0

### Which Node.JS version are you using?

v10

### Which operating system are you using?

Ubuntu 20.04 lts

### Please provide some context for your error. For example, when did the error occur? What were you trying to achieve, and how?

Hello,
I am new to Hyperledger Caliper and I would like to benchmark my Besu (IBFT2) private network by adding the URL (websocket) of its RPC endpoint, in the networkconfig.json located in networks/ethereum/1node-clique.
 



### What was the observed incorrect behavior?

When I am trying to launch caliper, I’m gettting an error message which indicates that Caliper cannot communicate with my  private network. 
Logs seem to indicate that Caliper cannot communicate with my private network and I don't understand why since my private network is running. 

### Please provide the error logs and their surroundings.

```text
Here are the logs: 

2022.02.25-00:22:34.962 error [caliper] [caliper-engine]        Error while performing "init" step: Error: connection not open
2022.02.25-00:22:35.818 error [caliper] [cli-launch-manager]    Benchmark failed with error code 4
```


### Please provide your network configuration file content, if possible.

Here is my networkconfig.json: 
````
{
    "caliper": {
        "blockchain": "ethereum",
        "command" : {
            "start": "sudo docker-compose -f ./networks/ethereum/1node-clique/docker-compose.yml up -d && sleep 60s",
            "end" : "sudo docker-compose -f ./networks/ethereum/1node-clique/docker-compose.yml down"
          }
    },
    "ethereum": {
        "url": "ws://XX.XXX.XXX.XXX",
        "contractDeployerAddress": "0xc0A8e4D217eB85b812aeb1226fAb6F588943C2C2",
        "contractDeployerAddressPassword": "password",
        "fromAddress": "0xc0A8e4D217eB85b812aeb1226fAb6F588943C2C2",
        "fromAddressPassword": "password",
        "transactionConfirmationBlocks": 2,
        "contracts": {
            "simple": {
                "path": "./src/ethereum/simple/simple.json",
                "estimateGas": true,
                "gas": {
                    "query": 100000,
                    "transfer": 70000
                }
            }
        }
    }
}
  ````


### Please provide any additional information you deem relevant to the error.

Here are the commands that I’m using:
```
npm init -y
npm install --only=prod \ @hyperledger/caliper-cli@0.4.0
npx caliper launch manager \
    --caliper-bind-sut besu:latest \
    --caliper-workspace . \
    --caliper-benchconfig benchmarks/scenario/simple/config.yaml \
    --caliper-networkconfig networks/ethereum/1node-clique/networkconfig.json
```

component/besu

 A blockchain benchmark framework to measure performance of multiple blockchain solutions https://wiki.hyperledger.org/display/caliper

caliper

JavaScript

Error while performing "init" step: Error: connection not open

Our build matrix is unnecessarily wide, which slows down each CI run (since separate VMs have to be spawned for each instance):

```yaml
  pe-parse:
    strategy:
      matrix:
        platform: ["ubuntu-18.04", "macos-latest"]
        build-type: ["Debug", "Release"]
        build-shared: ["0", "1"]
        compiler:
        - { CC: "clang", CXX: "clang++" }
        - { CC: "gcc", CXX: "g++" }
        exclude:
        - platform: macos-latest
          compiler: { CC: "gcc", CXX: "g++" }
```

We can flatten this a bit by running debug/release and shared/static builds in the same release jobs, as separate steps.

pe-parse

Reduce our build matrix

### Discussed in https://github.com/trailofbits/maat/discussions/48

<div type='discussions-op-text'>

<sup>Originally posted by **novafacing** February 24, 2022</sup>
Is there a way to either explicitly set or access the address libraries are loaded at? I'm using `angr` to extract some PLT information and trying to set a callback in `maat` on the PLT stub address in the loaded library, but the addresses don't match up.

I'm using the Python interface. Thanks!</div>

#48 explains that memory mappings are currently accessible only from the C++ API. While @novafacing posted a workaround script to get the mappings programatically we should eventually add python bindings for the `MemEngine.mappings` attribute and the `MemMapManager` class. 

bindings

Good first issue

Open-source symbolic execution framework: https://maat.re

maat

Expose memory mappings in Python API

Guidelines and training material to write secure smart contracts

building-secure-contracts

Create list of risks when interacting with the most common DeFi

We have observed that below ERROR level log is getting printed for every invalid transaction sdk receives and we think that this log should be at INFO level.
Receiving invalid transaction should not be considered as failure case, it is a BAU case.
```
2021-11-22 12:00:02.254 [pool-6-thread-173] ERROR Channel - Future completed exceptionally: sendTransaction
org.hyperledger.fabric.sdk.exception.TransactionEventException: Received invalid transaction event. Transaction ID b9c18e9a84ef12a4e3b553816c5bf008c4c9469a675631f0f508539d55b851ff status 11
at org.hyperledger.fabric.sdk.Channel$TL.lambda$fire$2(Channel.java:6866) ~[fabric-sdk-java-2.2.3.jar!/:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_271]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_271]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_271]
```
Using low level java sdk 2.2.3.

After some discussion, the issue is that if the low-level fabric-sdk-java Channel.sendTransaction() method is used directly and configured (or defaults) to waiting for transaction commit events, an MVCC_READ_CONFLICT can occur and will be logged as an error in the SDK log.  However this is not technically an error as an MVCC_READ_CONFLICT means the transaction is properly invalidated until the world state is read again.

Unfortunately, the logging for the Channel.sendTransaction() method uses the same code path for logging real transaction failures as well as non failures such as MVCC_READ_CONFLICTS.

The request is that a change be made such that actual errors are logged as errors and non errors are logged as info or warning.  I believe this would require the code to try and guess the severity from a transaction validation code if one is associated with the error.

We also discussed changing the log level for any errors from Channel.sendTransaction() to warning.  However, this would mask real errors in the logs and may affect other users who are scraping the logs for error messages.

The high level SDK uses a different flow so does not have this issue.  Obviously though it's work for users to move to that SDK who are already using the low level SDK.

Contribute to open-source Web3 projects

✨ Ethereum.org

✨ Privacy & Scaling Explorations

✨ Solidity

Handle BLS portable vs modern distinction in CI cache

`UnimplementedFeatureError` with no line indication when copying an array of structs to storage

Private function names should not be checked for uniqueness when inherited by other contracts

forge install/remove should automatically update remappings.txt and foundry.toml

Improper Usage Of Time And Tickers in Tests

Consistently use `type` instead of `interface` across the codebase.

Improving --walletdir vs --datadir flag UX

Support slashers

NullPointerException trying to handle an unannotated return type via contract-api

Use upstream Unicorn

Add eslint support

Add eslint support

Explicitly declare minimum required Node.js version for any project that uses Node.js.

Fix handling of `api-token.txt` and `validator_key_cache.json` when disk is full

Support newer LLVM versions

Error while performing "init" step: Error: connection not open

Reduce our build matrix

Expose memory mappings in Python API

Create list of risks when interacting with the most common DeFi

Separate logging of warnings and errors in channel.sendTransaction() method in low level java SDK

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