## Proposed Changes
With proposer boosting implemented (#2822) we have an opportunity to re-org out late blocks.
This PR adds three flags to the BN to control this behaviour:
* `--disable-proposer-reorgs`: turn aggressive re-orging off (it's on by default).
* `--proposer-reorg-threshold N`: attempt to orphan blocks with less than N% of the committee vote. If this parameter isn't set then N defaults to 20% when the feature is enabled.
* `--proposer-reorg-epochs-since-finalization N`: only attempt to re-org late blocks when the number of epochs since finalization is less than or equal to N. The default is 2 epochs, meaning re-orgs will only be attempted when the chain is finalizing optimally.
For safety Lighthouse will only attempt a re-org under very specific conditions:
1. The block being proposed is 1 slot after the canonical head, and the canonical head is 1 slot after its parent. i.e. at slot `n + 1` rather than building on the block from slot `n` we build on the block from slot `n - 1`.
2. The current canonical head received less than N% of the committee vote. N should be set depending on the proposer boost fraction itself, the fraction of the network that is believed to be applying it, and the size of the largest entity that could be hoarding votes.
3. The current canonical head arrived after the attestation deadline from our perspective. This condition was only added to support suppression of forkchoiceUpdated messages, but makes intuitive sense.
4. The block is being proposed in the first 2 seconds of the slot. This gives it time to propagate and receive the proposer boost.
## Additional Info
For the initial idea and background, see: https://github.com/ethereum/consensus-specs/pull/2353#issuecomment-950238004
There is also a specification for this feature here: https://github.com/ethereum/consensus-specs/pull/3034
Co-authored-by: Michael Sproul <micsproul@gmail.com>
Co-authored-by: pawan <pawandhananjay@gmail.com>
## Issue Addressed
N/A
## Proposed Changes
Make simulator merge compatible. Adds a `--post_merge` flag to the eth1 simulator that enables a ttd and simulates the merge transition. Uses the `MockServer` in the execution layer test utils to simulate a dummy execution node.
Adds the merge transition simulation to CI.
## Description
Add a new lint to CI that attempts to detect calls to functions like `block_on` from async execution contexts. This lint was written from scratch exactly for this purpose, on my fork of Clippy: https://github.com/michaelsproul/rust-clippy/tree/disallow-from-async
## Additional Info
- I've successfully detected the previous two issues we had with `block_on` by running the linter on the commits prior to each of these PRs: https://github.com/sigp/lighthouse/pull/3165, https://github.com/sigp/lighthouse/pull/3199.
- The lint runs on CI with `continue-on-error: true` so that if it fails spuriously it won't block CI.
- I think it would be good to merge this PR before https://github.com/sigp/lighthouse/pull/3244 so that we can lint the extensive executor-related changes in that PR.
- I aim to upstream the lint to Clippy, at which point building a custom version of Clippy from my fork will no longer be necessary. I imagine this will take several weeks or months though, because the code is currently a bit hacky and will need some renovations to pass review.
## Issue Addressed
`make lint` failing on rust 1.53.0.
## Proposed Changes
1.53.0 updates
## Additional Info
I haven't figure out why yet, we were now hitting the recursion limit in a few crates. So I had to add `#![recursion_limit = "256"]` in a few places
Co-authored-by: realbigsean <seananderson33@gmail.com>
Co-authored-by: Michael Sproul <michael@sigmaprime.io>
