This disentangles the script validation skipping from checkpoints.
A new option is introduced "assumevalid" which specifies a block whos
ancestors we assume all have valid scriptsigs and so we do not check
them when they are also burried under the best header by two weeks
worth of work.
Unlike checkpoints this has no influence on consensus unless you set
it to a block with an invalid history. Because of this it can be
easily be updated without risk of influencing the network consensus.
This results in a massive IBD speedup.
This approach was independently recommended by Peter Todd and Luke-Jr
since POW based signature skipping (see PR#9180) does not have the
verifiable properties of a specific hash and may create bad incentives.
The downside is that, like checkpoints, the defaults bitrot and older
releases will sync slower. On the plus side users can provide their
own value here, and if they set it to something crazy all that will
happen is more time will be spend validating signatures.
Checkblocks and checklevel are also moved to the hidden debug options:
Especially now that checkblocks has a low default there is little need
to change these settings, and users frequently misunderstand them as
influencing security or IBD speed. By hiding them we offset the
space added by this new option.
Make a more conservative notion of whether the node is caught up to the rest of the network and only count transactions as fee estimation data points if the node is caught up.
749be01 Move GetWarnings() into its own file. (Gregory Maxwell)
e3ba0ef Eliminate data races for strMiscWarning and fLargeWork*Found. (Gregory Maxwell)
c63198f Make QT runawayException call GetWarnings instead of directly access strMiscWarning. (Gregory Maxwell)
dd0df81 Document ConnectBlock connectTrace postconditions (Matt Corallo)
2d6e561 Switch pblock in ProcessNewBlock to a shared_ptr (Matt Corallo)
2736c44 Make the optional pblock in ActivateBestChain a shared_ptr (Matt Corallo)
ae4db44 Create a shared_ptr for the block we're connecting in ActivateBCS (Matt Corallo)
fd9d890 Keep blocks as shared_ptrs, instead of copying txn in ConnectTip (Matt Corallo)
6fdd43b Add struct to track block-connect-time-generated info for callbacks (Matt Corallo)
