<oembed><type>rich</type><version>1.0</version><author_name>npub10z4xjfgftd3fm9dfu7dw6mkemgyhxgumcmhd7yd0ggjq7rsaw4wqa3xfzw</author_name><author_url>https://nostr.ae/npub10z4xjfgftd3fm9dfu7dw6mkemgyhxgumcmhd7yd0ggjq7rsaw4wqa3xfzw</author_url><provider_name>njump</provider_name><provider_url>https://nostr.ae</provider_url><html>📅 Original date posted:2016-11-16&#xA;📝 Original message:I think we are misunderstanding the effect of this change.&#xA;It&#39;s still &#34;OK&#34; for a 50k re-org to happen.&#xA;We&#39;re just saying that if it does, we will now have potentially introduced&#xA;a hard fork between new client and old clients if the reorg contains&#xA;earlier signaling for the most recent ISM soft fork and then blocks which&#xA;do not conform to that soft fork before the block height encoded activation.&#xA;&#xA;I think the argument is this doesn&#39;t substantially add to the confusion or&#xA;usability of the system as its likely that old software won&#39;t even handle&#xA;50k block reorgs cleanly anyway and there will clearly have to be human&#xA;coordination at the time of the event.  In the unlikely event that the new&#xA;chain does cause such a hard fork, that coordination can result in everyone&#xA;upgrading to software that supports the new rules anyway.&#xA;&#xA;So no, I don&#39;t think we should add a checkpoint.  I think we should all&#xA;just agree to a hard fork that only has a very very slim chance of any&#xA;practical effect.&#xA;&#xA;In response to Thomas&#39; email.  I think ideally we would treat these soft&#xA;forks the way we did BIP30 which is to say that we&#39;re just introducing a&#xA;further soft fork that applies to all blocks except for the historical&#xA;exceptions.  So then its a almost no-op soft fork with no risk of hard&#xA;fork.   This however isn&#39;t practical with at least BIP 34 without storing&#xA;the hashes of all 200K blocks that don&#39;t meet the requirement.&#xA;&#xA;&#xA;&#xA;On Wed, Nov 16, 2016 at 9:18 AM, Tier Nolan via bitcoin-dev &lt;&#xA;bitcoin-dev at lists.linuxfoundation.org&gt; wrote:&#xA;&#xA;&gt; On Wed, Nov 16, 2016 at 1:58 PM, Eric Voskuil via bitcoin-dev &lt;&#xA;&gt; bitcoin-dev at lists.linuxfoundation.org&gt; wrote:&#xA;&gt;&#xA;&gt;&gt; Are checkpoints good now? Are hard forks okay now?&#xA;&gt;&gt;&#xA;&gt;&#xA;&gt; I think that at least one checkpoint should be included.  The assumption&#xA;&gt; is that no 50k re-orgs will happen, and that assumption should be directly&#xA;&gt; checked.&#xA;&gt;&#xA;&gt; Checkpointing only needs to happen during the headers-first part of the&#xA;&gt; download.&#xA;&gt;&#xA;&gt; If the block at the BIP-65 height is checkpointed, then the comparisons&#xA;&gt; for the other ones are automatically correct.  They are unnecessary, since&#xA;&gt; the checkpoint protects all earlier block, but many people would like to be&#xA;&gt; able to verify the legacy chain.&#xA;&gt;&#xA;&gt; This makes the change a soft-fork rather than a hard fork.  Chains that&#xA;&gt; don&#39;t go through the checkpoint are rejected but no new chains are allowed.&#xA;&gt;&#xA;&gt; _______________________________________________&#xA;&gt; bitcoin-dev mailing list&#xA;&gt; bitcoin-dev at lists.linuxfoundation.org&#xA;&gt; https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev&#xA;&gt;&#xA;&gt;&#xA;-------------- next part --------------&#xA;An HTML attachment was scrubbed...&#xA;URL: &lt;http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20161116/5e407283/attachment-0001.html&gt;</html></oembed>