Please describe the feature you'd like to see added.

From #27446 (comment):

This brings up a related issue in that we can't have multiple signets in the same base datadir. All signets use the signet datadir, so any change of parameter may result in a bad chainstate for that signet node.

I think we should instead look at implementing a more robust multiple signet solution that allows for multiple configurable consensus rules in a clean and simple way since clearly that's desired. Ideally we would have a single parameter that contains all of the rules being configured rather than having multiple for each rule. We should also make datadirs specific to each set of rules, ideally in a deterministic way.

cc @achow101 @kallewoof

An option might be to name the chain dir signet-XXXXXXXX instead of signet where the XXs are the pchMessageStart, or perhaps to have ~40 XXs instead of 8 and have them be the hash160 of the signet challenge?

This looks like a breaking change, so one could carve out the current global default signet to keep the current folder name. Though, for other signets this breaking change seems fine.

Hi

We're students at UT Austin looking for an issue to work on for our course project. We are interested in this issue and aim to raise PR and get it approved within a month. We will appreciate your help.

Regards

Useful Skills

• Compiling Bitcoin Core from source
• Running the C++ unit tests and the Python functional tests
• Basic signet understanding, Running signet
• Basic understanding of the datadir handling in Bitcoin Core

Guidance for new contributors

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Hey, @theartpiece, Are you still working on this issue? If not, I’d like to pick it up. Thanks

I think that following scripts are related and may serve as an inspiration while keeping backward-compatibility.

bch.sh

For bitcoin-cli, this is bch.sh ("bitcoin cli here")

#!/bin/sh

test -d "$1" && { cd "$1"; shift; }
test -d .bitcoin && cd .bitcoin

# Handling of inside-the-wallet-dir cases
echo $PWD | grep -q '/wallets' && {
  mypwd=$PWD
  until test "${PWD##*/}" = "wallets"; do cd ..; done
  wn=${mypwd##$PWD/}
  w="-rpcwallet=${wn}"
  test "$1" = "loadwallet" && add="$wn"
  cd ..
}

test "${PWD##*/}" = "signet" && chain=signet
test "${PWD##*/}" = "testnet3" && chain=test
test "${PWD##*/}" = "regtest" && chain=regtest
test "$chain" = "" || ddir=${PWD%/*}

exec bitcoin-cli $w -datadir=${ddir:-$PWD} -chain=${chain:-main} "$@" $add

bdh.sh

Following is bdh.sh (“bitcoin daemon here")

#!/bin/sh

test -d "$1" && { cd "$1"; shift; }
test -d .bitcoin && cd .bitcoin

test "${PWD##*/}" = "signet" && chain=signet
test "${PWD##*/}" = "testnet3" && chain=test
test "${PWD##*/}" = "regtest" && chain=regtest
test "$chain" = "" || ddir=${PWD%/*}

exec bitcoind "-datadir=${ddir:-$PWD}" -chain=${chain:-main} "$@"

Usage

cd /tmp
mkdir -p tmpb/regtest
cd tmpb/regtest
bdh.sh -daemon
bch.sh help

HTH

Hey, as I haven't seen this being tackled I will happily undertake it. Currently working on it at https://github.com/InsanityMatrix/bitcoin on branch "signet-datadir-changes"

I plan to start with the initialization files and work my way through the files to change any references to the block directory depending on if it is a signet chain. and also plan on making it backwards compatible. Any help would be appreciated, just mention me if you have any ideas or contributions! :)