* begin 0.5.0 spec update: parent_root -> previous_block_root, BeaconState.justified_epoch -> BeaconState.current_justified_epoch, DOMAIN_PROPOSAL -> DOMAIN_BEACON_BLOCK, temporarily rename BeaconBlockHeader to BeaconBlockHeaderRLP to allow for gradual re-merging without disrupting RLP; mark a few unchanged functions and data types, implement get_temporary_block_header/get_empty_block/should_update_validator_registry/processBlockHeader/cacheState; update a few others
* a dozen or so more trivial mostly comment changes, finding more unchanged parts of 0.5.0
* several more trivial changes; goal is to reduce noise around the upcoming substantial changes (epoch processing, etc)
* keep track of a finalized block
* keep track of all justified blocks
* use naive spec version of LMD ghost
* cache slot number and a few more things in BlockRef
* keep track of the latest vote of each validator
* depend less on the state of node.state (it's a cache, effectively)
Passing along no-name command line arguments when using make (from Nimbus) would need make target revamps that are a bit clumsy AFAIK, so using environment variables in the spirit of USE_MULTITAIL to get the number of validators and nodes makes more sense to me.
This lets us run the sim from nim-beacon-chain with
```bash
VALIDATORS=512 NODES=100 USE_MULTITAIL="yes" tests/simulation/start.sh
```
and from Nimbus with:
```bash
VALIDATORS=512 NODES=100 USE_MULTITAIL="yes" make eth2_network_simulation
```
Also makes for a more verbose launch process.
To enable it, comment out the 'withLibp2p' line in nim.cfg
The history was squashed in order to remove an accidentally
commited binary file.
Other changes:
* SSZ was adapted to use the common serialization framework
* gossibsup.subscribe is not using async handlers at the moment
and this allowed me to simplify it
* set epoch_boundary_root - chain finalizes!
* fix slotStart to offset GENESIS_SLOT
* work around bug that will be fixed by
https://github.com/ethereum/eth2.0-specs/pull/732
* compile with debug info (there was a GC-related crash in C land)
* fix state db lookup typo
* fix randao reveal slot when proposing blocks
* only store blocks that can be applied to a state
* store state at every epoch boundary (yes, needs pruning!)
* split out state advancement function when there's no block
* default state sim to 0.9 attestation ratio
* allow running more or fewer validators
* use deterministic key generation for tests to avoid exhausting system
RNG
* update README with simulator docs
* write the data of each validator to separate file, instead of a big
chainstart.json (makes it easier to run different validator counts)
* prevent balance underflow, per spec implementation note
* verify that permutation shuffing works: add YAML dependency to be used for ingesting test cases; switch from blake2 to keccak256 to match EF test cases; remove inefficient naive-spec-version of shuffling algorithm now that protolambda's can be tested directly
* Complete scan through v0.3.0 spec; remaining known discreptancy is in bls_verify_multiple
* switch remaining slot-misuses of get_active_validator_indices to epochs
* spec workaround
* finish first 0.3.0 pass by getting slow, naive version of bls_verify_multiple running
* implement in-memory block graph
* store tail block in database
* resolve unknown parents by syncing them from peers
* introduce concept of resolved blocks and attestations - those that
follow minimal protocol rules
* update state head lazily
* log more stuff
* shortHash -> shortLog
* start 9/10 beacon nodes by default, last can be started manually
* see also #134
* fix start.sh epoch length
* convert some asserts to doAsserts to keep them in release mode builds; rename get_initial_beacon_state to get_genesis_beacon_state to track spec; switch target spec version to 0.3.0; switch references to penalize_validator to slash_validator/slashValidator to track spec; make some function returns safer by omitting 'return'
* 2x shuffling speedup by hoisting pivot calculations per https://github.com/protolambda/eth2-shuffle
* fix initial attestation pool on reordered attestations
* simplify db layer api
* load head block from database on startup, then load state
* significantly changes database format
* move subscriptions to separate proc's
* implement block replay from historical state
* avoid rescheduling epoch actions on block receipt (why?)
* make sure genesis block is created and used
* relax initial state sim parameters a bit
* move attestation pool to separate file
* combine attestations lazily when needed
* advance state when there's a gap while attesting
* compile beacon node with optimizations - it's tooo slow right now
* log when unable to keep up
* s/slot_included/inclusion_slot/; s/participation_bitfield/aggregation_bitfield/; rearrange some type definitions to match spec order
* a couple more Eth1Data-related spec syncs
Dustin Brody
Ștefan Talpalaru
Jacek Sieka
Bruno Škvorc
Mamy André-Ratsimbazafy
Zahary Karadjov
Yuriy Glukhov
Jacek Sieka
Mamy Ratsimbazafy