Subject: Re: [bitcoindev] The Future of Bitcoin Testnet

From: Eric Voskuil <[email-masked]>
Date: Sun, 31 Mar 2024 13:21:07 -0400

On Mar 31, 2024, at 12:24, Jameson Lopp <[email-masked]> wrote:

On Sun, Mar 31, 2024 at 10:33 AM Luke Dashjr <[email-masked]> wrote:

Is the difficulty reset bug actually a bug, or a feature?

I haven't thought of or heard of any good reason why it's helpful to have a dozen blocks per second flood the network for several days every time the edge case gets hit.

Apart from the genesis block and fork activation points (data), easy blocks is the only line of code (logic) that distinguishes testnet3 from bitcoin.

I have always assumed it’s a feature intended to keep it very easy to produce blocks with the side effect of limiting monetary utility and preserving most of the adjustment logic.

If it’s eliminated there presumably must be some other change to produce those intended results. However it would be important to consider not only all of the dependencies that may be built up upon it, but also that the more it deviates from bitcoin the less useful it becomes for testing bitcoin.

If it's a bug, couldn't we just fix it and let the blockchain reorg on its own?

I believe so. Upon closer inspection I think it's actually a soft forkable fix if all we do is restrict the special testnet minimum difficulty rule so that it can't be triggered on the block right before a difficulty retarget.

Signet is definitely not a replacement for testnet.

Luke

On 3/31/24 09:19, Jameson Lopp wrote:

Hi all,

I'd like to open a discussion about testnet3 to put out some feelers on potential changes to it. First, a few facts:

1. Testnet3 has been running for 13 years. It's on block 2.5 million something and the block reward is down to ~0.014 TBTC, so mining is not doing a great job at distributing testnet coins any more.

2. The reason the block height is insanely high is due to a rather amusing edge case bug that causes the difficulty to regularly get reset to 1, which causes a bit of havoc. If you want a deep dive into the quirk: https://blog.lopp.net/the-block-storms-of-bitcoins-testnet/

3. Testnet3 is being actively used for scammy airdrops; those of us who tend to be generous with our testnet coins are getting hounded by non-developers chasing cheap gains.

4. As a result, TBTC is being actively bought and sold; one could argue that the fundamental principle of testnet coins having no value has been broken.

This leads me to ponder the following questions, for which I'm soliciting feedback.

1. Should we plan for a reset of testnet? If so, given how long it has been since the last reset and how many production systems will need to be updated, would a reset need to be done with a great deal of notice?

2. Is there interest in fixing the difficulty reset bug? It should be a one liner fix, and I'd argue it could be done sooner rather than later, and orthogonal to the network reset question. Would such a change, which would technically be a hard fork (but also arguably a self resolving fork due to the difficulty dynamics) necessitate a BIP or could we just YOLO it?

3. Is all of the above a waste of time and we should instead deprecate testnet in favor of signet?

- Jameson

--
You received this message because you are subscribed to the Google Groups "Bitcoin Development Mailing List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to [email-masked].
To view this discussion on the web visit https://groups.google.com/d/msgid/bitcoindev/CADL_X_eXjbRFROuJU0b336vPVy5Q2RJvhcx64NSNPH-3fDCUfw%40mail.gmail.com.

--
You received this message because you are subscribed to the Google Groups "Bitcoin Development Mailing List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to [email-masked].
To view this discussion on the web visit https://groups.google.com/d/msgid/bitcoindev/CADL_X_eZ3uDU7PPh11rn2NSGwvRMjjZ3Auu6eVVQoJU78%2BaRxQ%40mail.gmail.com.

--
You received this message because you are subscribed to the Google Groups "Bitcoin Development Mailing List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to [email-masked].
To view this discussion on the web visit https://groups.google.com/d/msgid/bitcoindev/629F8480-76E6-4A74-A24B-77A570F0FBB1%40voskuil.org.