Check validity of inputs and gracefully handle the error

[lacabra]

Is your feature request related to a problem? Please describe.

Core throws an exception when processing a request to deploy a SecretContract that includes a PreCode field with other characters that are not hex, for example, just prepending the string 0x to a hex string causes the following error:

core_1        | 03:54:44 [INFO] LOG DERIVE: Err(Invalid character 'x' at position 1
core_1        | 
core_1        | stack backtrace:
core_1        |    0: failure::backtrace::internal::InternalBacktrace::new::h0c85aeebdcdd7156 (0x557efe8fa8ae)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/failure-0.1.5/src/backtrace/internal.rs:44
core_1        |    1: failure::backtrace::Backtrace::new::hb2072042fb7e0676 (0x557efe8fa37d)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/failure-0.1.5/src/backtrace/mod.rs:111
core_1        |    2: <failure::error::error_impl::ErrorImpl as core::convert::From<F>>::from::h362099f92da07e9e (0x557efe3af1f6)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/failure-0.1.5/src/error/error_impl.rs:19
core_1        |    3: <failure::error::Error as core::convert::From<F>>::from::h6ccb66125461f3af (0x557efe3a744a)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/failure-0.1.5/src/error/mod.rs:36
core_1        |    4: enigma_core_app::networking::ipc_listener::handling::deploy_contract::{{closure}}::he9bae77b29db796c (0x557efe114e09)
core_1        |              at src/networking/ipc_listener.rs:307
core_1        |    5: enigma_core_app::networking::ipc_listener::handling::deploy_contract::h2667e8963674a2af (0x557efe1c1e4d)
core_1        |              at src/networking/ipc_listener.rs:307
core_1        |    6: enigma_core_app::networking::ipc_listener::handle_message::h1750df4bf26872f3 (0x557efe106c40)
core_1        |              at src/networking/ipc_listener.rs:48
core_1        |    7: enigma_core_app::main::{{closure}}::hf35b7eb5da2211fb (0x557efe09e944)
core_1        |              at src/main.rs:35
core_1        |    8: core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &'a mut F>::call_once::h0a1b12463a3b99c4 (0x557efe09e80a)
core_1        |              at libcore/ops/function.rs:286
core_1        |    9: <core::option::Option<T>>::map::h32de77ba92ca6014 (0x557efe09d0ec)
core_1        |              at libcore/option.rs:424
core_1        |   10: <futures::stream::map::Map<S, F> as futures::stream::Stream>::poll::h020ec7812c81f167 (0x557efe0beeba)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/stream/map.rs:79
core_1        |   11: <futures::stream::forward::Forward<T, U> as futures::future::Future>::poll::h9f24ac433f8d0533 (0x557efe0ac563)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/stream/forward.rs:94
core_1        |   12: <futures::future::map::Map<A, F> as futures::future::Future>::poll::hedf6c26bce1e517a (0x557efe0b65fd)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/future/map.rs:30
core_1        |   13: <futures::future::chain::Chain<A, B, C>>::poll::h9a56683a803d98e6 (0x557efe0c2dd5)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/future/chain.rs:32
core_1        |   14: <futures::future::and_then::AndThen<A, B, F> as futures::future::Future>::poll::h476e6dd9a7af70c0 (0x557efe0a9929)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/future/and_then.rs:32
core_1        |   15: <futures::task_impl::Spawn<T>>::poll_future_notify::{{closure}}::h8aac65f6c2b28787 (0x557efe09a899)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/mod.rs:329
core_1        |   16: <futures::task_impl::Spawn<T>>::enter::{{closure}}::h0dcbd4cb7cf055a1 (0x557efe09aa16)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/mod.rs:399
core_1        |   17: futures::task_impl::std::set::h42825b196f346936 (0x557efe0be11c)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/std/mod.rs:78
core_1        |   18: <futures::task_impl::Spawn<T>>::enter::h73545ec010aa3483 (0x557efe09a9a2)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/mod.rs:399
core_1        |   19: <futures::task_impl::Spawn<T>>::poll_fn_notify::hbab32881f8f24cdd (0x557efe09a7c4)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/mod.rs:291
core_1        |   20: <futures::task_impl::Spawn<T>>::poll_future_notify::h7d6ea848a1928f74 (0x557efe09a86d)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/mod.rs:329
core_1        |   21: futures::task_impl::std::<impl futures::task_impl::Spawn<F>>::wait_future::{{closure}}::h007f83165af89296 (0x557efe0be1f8)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/std/mod.rs:231
core_1        |   22: futures::task_impl::std::ThreadNotify::with_current::{{closure}}::h2a26e648c9ac6231 (0x557efe0be02e)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/std/mod.rs:478
core_1        |   23: <std::thread::local::LocalKey<T>>::try_with::h2a5cc9a7429097dd (0x557efe09ca23)
core_1        |              at libstd/thread/local.rs:294
core_1        |   24: <std::thread::local::LocalKey<T>>::with::hc1a5d9c54e7a9872 (0x557efe09c820)
core_1        |              at libstd/thread/local.rs:248
core_1        |   25: futures::task_impl::std::ThreadNotify::with_current::hd3630610c1e4cdc4 (0x557efe0bdfed)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/std/mod.rs:478
core_1        |   26: futures::task_impl::std::<impl futures::task_impl::Spawn<F>>::wait_future::h9b449006e78c92e2 (0x557efe09aa43)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/std/mod.rs:228
core_1        |   27: futures::future::Future::wait::h65ec1379a489e9f4 (0x557efe0a9b21)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/future/mod.rs:299
core_1        |   28: enigma_core_app::main::h51e5e13b67620211 (0x557efe0a7164)
core_1        |              at src/main.rs:34
core_1        |   29: std::rt::lang_start::{{closure}}::hf50adf6ebd355f61 (0x557efe0b04ef)
core_1        |              at libstd/rt.rs:74
core_1        |   30: std::rt::lang_start_internal::{{closure}}::hdc2a896aeffb5179 (0x557efedc62d2)
core_1        |              at libstd/rt.rs:59
core_1        |       std::panicking::try::do_call::h5a4eb2ce70a501f5
core_1        |              at libstd/panicking.rs:310
core_1        |   31: __rust_maybe_catch_panic (0x557efede7229)
core_1        |              at libpanic_unwind/lib.rs:102
core_1        |   32: std::panicking::try::h97436c380f30f437 (0x557efedc8795)
core_1        |              at libstd/panicking.rs:289
core_1        |       std::panic::catch_unwind::h9c28ef6e0c478c5d
core_1        |              at libstd/panic.rs:392
core_1        |       std::rt::lang_start_internal::h6abd6befa9748e41
core_1        |              at libstd/rt.rs:58
core_1        |   33: std::rt::lang_start::h28de98d2c46239d3 (0x557efe0b04c7)
core_1        |              at libstd/rt.rs:74
core_1        |   34: main (0x557efe0a72f9)
core_1        |   35: __libc_start_main (0x7f124ae30b96)
core_1        |   36: _start (0x557efe099b09)
core_1        |   37: <unknown> (0x0))
core_1        | 03:54:44 [ERROR] Unwrapped p2p Message failed: Invalid character 'x' at position 1
core_1        | 
core_1        | stack backtrace:
core_1        |    0: failure::backtrace::internal::InternalBacktrace::new::h0c85aeebdcdd7156 (0x557efe8fa8ae)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/failure-0.1.5/src/backtrace/internal.rs:44
core_1        |    1: failure::backtrace::Backtrace::new::hb2072042fb7e0676 (0x557efe8fa37d)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/failure-0.1.5/src/backtrace/mod.rs:111
core_1        |    2: <failure::error::error_impl::ErrorImpl as core::convert::From<F>>::from::h362099f92da07e9e (0x557efe3af1f6)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/failure-0.1.5/src/error/error_impl.rs:19
core_1        |    3: <failure::error::Error as core::convert::From<F>>::from::h6ccb66125461f3af (0x557efe3a744a)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/failure-0.1.5/src/error/mod.rs:36
core_1        |    4: enigma_core_app::networking::ipc_listener::handling::deploy_contract::{{closure}}::he9bae77b29db796c (0x557efe114e09)
core_1        |              at src/networking/ipc_listener.rs:307
core_1        |    5: enigma_core_app::networking::ipc_listener::handling::deploy_contract::h2667e8963674a2af (0x557efe1c1e4d)
core_1        |              at src/networking/ipc_listener.rs:307
core_1        |    6: enigma_core_app::networking::ipc_listener::handle_message::h1750df4bf26872f3 (0x557efe106c40)
core_1        |              at src/networking/ipc_listener.rs:48
core_1        |    7: enigma_core_app::main::{{closure}}::hf35b7eb5da2211fb (0x557efe09e944)
core_1        |              at src/main.rs:35
core_1        |    8: core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &'a mut F>::call_once::h0a1b12463a3b99c4 (0x557efe09e80a)
core_1        |              at libcore/ops/function.rs:286
core_1        |    9: <core::option::Option<T>>::map::h32de77ba92ca6014 (0x557efe09d0ec)
core_1        |              at libcore/option.rs:424
core_1        |   10: <futures::stream::map::Map<S, F> as futures::stream::Stream>::poll::h020ec7812c81f167 (0x557efe0beeba)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/stream/map.rs:79
core_1        |   11: <futures::stream::forward::Forward<T, U> as futures::future::Future>::poll::h9f24ac433f8d0533 (0x557efe0ac563)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/stream/forward.rs:94
core_1        |   12: <futures::future::map::Map<A, F> as futures::future::Future>::poll::hedf6c26bce1e517a (0x557efe0b65fd)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/future/map.rs:30
core_1        |   13: <futures::future::chain::Chain<A, B, C>>::poll::h9a56683a803d98e6 (0x557efe0c2dd5)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/future/chain.rs:32
core_1        |   14: <futures::future::and_then::AndThen<A, B, F> as futures::future::Future>::poll::h476e6dd9a7af70c0 (0x557efe0a9929)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/future/and_then.rs:32
core_1        |   15: <futures::task_impl::Spawn<T>>::poll_future_notify::{{closure}}::h8aac65f6c2b28787 (0x557efe09a899)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/mod.rs:329
core_1        |   16: <futures::task_impl::Spawn<T>>::enter::{{closure}}::h0dcbd4cb7cf055a1 (0x557efe09aa16)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/mod.rs:399
core_1        |   17: futures::task_impl::std::set::h42825b196f346936 (0x557efe0be11c)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/std/mod.rs:78
core_1        |   18: <futures::task_impl::Spawn<T>>::enter::h73545ec010aa3483 (0x557efe09a9a2)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/mod.rs:399
core_1        |   19: <futures::task_impl::Spawn<T>>::poll_fn_notify::hbab32881f8f24cdd (0x557efe09a7c4)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/mod.rs:291
core_1        |   20: <futures::task_impl::Spawn<T>>::poll_future_notify::h7d6ea848a1928f74 (0x557efe09a86d)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/mod.rs:329
core_1        |   21: futures::task_impl::std::<impl futures::task_impl::Spawn<F>>::wait_future::{{closure}}::h007f83165af89296 (0x557efe0be1f8)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/std/mod.rs:231
core_1        |   22: futures::task_impl::std::ThreadNotify::with_current::{{closure}}::h2a26e648c9ac6231 (0x557efe0be02e)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/std/mod.rs:478
core_1        |   23: <std::thread::local::LocalKey<T>>::try_with::h2a5cc9a7429097dd (0x557efe09ca23)
core_1        |              at libstd/thread/local.rs:294
core_1        |   24: <std::thread::local::LocalKey<T>>::with::hc1a5d9c54e7a9872 (0x557efe09c820)
core_1        |              at libstd/thread/local.rs:248
core_1        |   25: futures::task_impl::std::ThreadNotify::with_current::hd3630610c1e4cdc4 (0x557efe0bdfed)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/std/mod.rs:478
core_1        |   26: futures::task_impl::std::<impl futures::task_impl::Spawn<F>>::wait_future::h9b449006e78c92e2 (0x557efe09aa43)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/task_impl/std/mod.rs:228
core_1        |   27: futures::future::Future::wait::h65ec1379a489e9f4 (0x557efe0a9b21)
core_1        |              at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.26/src/future/mod.rs:299
core_1        |   28: enigma_core_app::main::h51e5e13b67620211 (0x557efe0a7164)
core_1        |              at src/main.rs:34
core_1        |   29: std::rt::lang_start::{{closure}}::hf50adf6ebd355f61 (0x557efe0b04ef)
core_1        |              at libstd/rt.rs:74
core_1        |   30: std::rt::lang_start_internal::{{closure}}::hdc2a896aeffb5179 (0x557efedc62d2)
core_1        |              at libstd/rt.rs:59
core_1        |       std::panicking::try::do_call::h5a4eb2ce70a501f5
core_1        |              at libstd/panicking.rs:310
core_1        |   31: __rust_maybe_catch_panic (0x557efede7229)
core_1        |              at libpanic_unwind/lib.rs:102
core_1        |   32: std::panicking::try::h97436c380f30f437 (0x557efedc8795)
core_1        |              at libstd/panicking.rs:289
core_1        |       std::panic::catch_unwind::h9c28ef6e0c478c5d
core_1        |              at libstd/panic.rs:392
core_1        |       std::rt::lang_start_internal::h6abd6befa9748e41
core_1        |              at libstd/rt.rs:58
core_1        |   33: std::rt::lang_start::h28de98d2c46239d3 (0x557efe0b04c7)
core_1        |              at libstd/rt.rs:74
core_1        |   34: main (0x557efe0a72f9)
core_1        |   35: __libc_start_main (0x7f124ae30b96)
core_1        |   36: _start (0x557efe099b09)
core_1        |   37: <unknown> (0x0)

Describe the solution you'd like

It should gracefully return an error indicating that the input is invalid, more like:

core_1        | Error in deployment of smart contract function: Invalid input
core_1        | 04:02:04 [INFO] LOG DERIVE: Ok(FailedTask { result: FailedTask { output: "fede52db9527ba010fc2edd2635df8a1dd6435c83b9cec25b420e3e83014ec51970643341fabb8f6d354681c3783ba714edc569404decbf9d4ae316123f68d541a8c5ad2b4579b05c9e7866fbd4e182272b99cc284505b8f3dd150ca097c3cf22d64fcd6661b19a15656e61c847cf02957c075eec278280b45", used_gas: 0, signature: "2aec98dc09a440e52050d82c84e255774d97d3faf02a6a376ea42a2714c10ed139256eb165a0d69a9393fe2ee33c64a1832dd148aa56030725185e164851bbcf1b" } })

[elichai]

That's weird. can you give me a sample of data?
I can't see any unwraps there.

[moriaab]

If I try to add "0x" to a pre_code, there is no exception. The following happens:
to_hex fails here https://github.com/enigmampc/enigma-core/blob/develop/enigma-core/app/src/networking/ipc_listener.rs#L309
and then IpcResponse::Error is created (as expected).

@elichai, as far as I understand, we have 2 relevant unwraps:
https://github.com/enigmampc/enigma-core/blob/develop/enigma-core/app/src/networking/messages.rs#L219
https://github.com/enigmampc/enigma-core/blob/develop/enigma-core/app/src/main.rs#L37
But I don't see any problems with them in this case.
This defect reveals some issue. Although the problem is wrong user input, system error is returned. Is this what we want?

[moriaab]

This defect is planned to be fixed as part of general improvement of treating wrong inputs for deployment and computation of secret contracts.