The bug of validator set contract, how to solve this ?

[RustMan88]

Before filing a new issue, please provide the following information.

• Parity Ethereum version: v2.1.10
• Operating system: Linux
• Installation: built from source
• Fully synchronized: yes
• Network: private-poa
• Restarted: no

Your issue description goes here below. Try to include actual vs. expected behavior and steps to reproduce the issue.

2018-12-19 13:02:23 UTC main INFO parity_ethereum::run Starting Parity-Ethereum/v2.1.10-stable-b47e064-20181213/x86_64-linux-gnu/rustc1.31.0
2018-12-19 13:02:23 UTC main INFO parity_ethereum::run Keys path /home/ubuntu/DFChain/deploy/aura/node4/parity/keys/DemoPoA
2018-12-19 13:02:23 UTC main INFO parity_ethereum::run DB path /home/ubuntu/DFChain/deploy/aura/node4/parity/chains/DemoPoA/db/8683a0755a596f74
2018-12-19 13:02:23 UTC main INFO parity_ethereum::run State DB configuration: fast
2018-12-19 13:02:23 UTC main INFO parity_ethereum::run Operating mode: active
2018-12-19 13:02:23 UTC main INFO ethcore_service::service Configured for DemoPoA using AuthorityRound engine
2018-12-19 13:02:23 UTC main TRACE engine Setting up contract caller.
2018-12-19 13:02:58 UTC IO Worker #1 INFO import 0/25 peers 8 KiB chain 7 KiB db 0 bytes queue 448 bytes sync RPC: 0 conn, 0 req/s, 0 µs
2018-12-19 13:03:28 UTC IO Worker #2 INFO import 0/25 peers 8 KiB chain 7 KiB db 0 bytes queue 448 bytes sync RPC: 0 conn, 0 req/s, 0 µs
2018-12-19 13:03:58 UTC IO Worker #2 INFO import 0/25 peers 8 KiB chain 7 KiB db 0 bytes queue 448 bytes sync RPC: 0 conn, 0 req/s, 0 µs
2018-12-19 13:04:24 UTC IO Worker #0 DEBUG engine Zooming to epoch for block 0xa6e0…9b41

====================

stack backtrace:
0: 0x559d6f127c2d - backtrace::backtrace::trace::h9cba09a270894780
1: 0x559d6f126e42 - <backtrace::capture::Backtrace as core::default::Default>::default::h2d345f667ea34cba
2: 0x559d6f126eb9 - backtrace::capture::Backtrace::new::hf3eec8642311a0b2
3: 0x559d6f125ff6 - panic_hook::gen_panic_msg::h7b5e21c89f35fc42
4: 0x559d6da5e4b8 - panic_hook::set_with::{{closure}}::hdffd676768cd82e5
5: 0x559d6f19f516 - std::panicking::rust_panic_with_hook::h71214e7ce0f7ac01
at libstd/panicking.rs:480
6: 0x559d6f19f061 - std::panicking::continue_panic_fmt::ha8b8442f4ea9bcac
at libstd/panicking.rs:390
7: 0x559d6f19ef45 - rust_begin_unwind
at libstd/panicking.rs:325
8: 0x559d6f1e903c - core::panicking::panic_fmt::h0c93626b89c38af6
at libcore/panicking.rs:77
9: 0x559d6e8144f9 - core::result::unwrap_failed::hb04ee4352e50f551
10: 0x559d6e65a05d - ethcore::engines::authority_round::EpochManager::zoom_to::h5122e22957ff67c1
11: 0x559d6e65e540 - ethcore::engines::authority_round::AuthorityRound::epoch_set::h082ad54e3338ff48
12: 0x559d6e66161d - <ethcore::engines::authority_round::AuthorityRound as ethcore::engines::Engineethcore::machine::EthereumMachine>::generate_seal::ha7db97a68c107298
13: 0x559d6e895e83 - <ethcore::miner::miner::Miner as ethcore::miner::MinerService>::update_sealing::hcf909f50cf25415d
14: 0x559d6e65f4f0 - <ethcore::engines::authority_round::TransitionHandler as ethcore_io::IoHandler<()>>::timeout::hebad16ff08cc1705
15: 0x559d6e870a3e - ethcore_io::worker::Worker::work_loop::h5c0d2b4620a73848
16: 0x559d6e634c68 - std::sys_common::backtrace::__rust_begin_short_backtrace::h71a26d78574acaa9
17: 0x559d6e6e0996 - std::panicking::try::do_call::h3dc5da9921f9acc7
18: 0x559d6f1b1979 - __rust_maybe_catch_panic
at libpanic_unwind/lib.rs:102
19: 0x559d6e758d57 - <F as alloc::boxed::FnBox>::call_box::h2137ad7c234a0bcc
20: 0x559d6f19b9ad - <alloc::boxed::Box<(dyn alloc::boxed::FnBox<A, Output=R> + 'a)> as core::ops::function::FnOnce>::call_once::he3acfc8f1203786f
at liballoc/boxed.rs:682
- std::sys_common::thread::start_thread::h5213f803a61d7811
at libstd/sys_common/thread.rs:24
21: 0x559d6f186425 - std::sys::unix::thread::Thread::new::thread_start::he89121f566d2a8c7
at libstd/sys/unix/thread.rs:90
22: 0x7f883e3d36b9 - start_thread
23: 0x7f883def341c - clone
24: 0x0 -

Thread 'IO Worker #0' panicked at 'proof produced by this engine; therefore it is valid; qed: Error(Decoder(RlpExpectedToBeList), State { next_error: None, backtrace: InternalBacktrace { backtrace: None } })', libcore/result.rs:1009

This is a bug. Please report it at:

https://github.com/paritytech/parity-ethereum/issues/new

2018-12-19 13:04:24 UTC main INFO parity_ethereum::run Finishing work, please wait...

Anybody know how to solve this bug? thanks very much!

[jam10o-new]

Duplicate of #9509 - can you read through that and make sure your chainspec is correctly formatted?