Smart Contracts: Catch the invalid elixir syntax error in smart contracts

[bchamagne]

Description

When a smart contract was using non elixir-valid syntax, an error was raised and the start_mining process crashed without return an error to the end user.

Following log happened when omitting a space in a keyword list: triggered_by:transaction

2023-05-03 12:45:48.137 [error] GenServer #PID<0.9153.0> terminating
** (ArgumentError) errors were found at the given arguments:

  * 1st argument: not an atom

    :erlang.atom_to_list({:atom, "triggered_by"})
    (elixir 1.14.1) src/elixir_tokenizer.erl:669: :elixir_tokenizer.tokenize/5
    (elixir 1.14.1) src/elixir.erl:371: :elixir.string_to_tokens/5
    (elixir 1.14.1) lib/code.ex:965: Code.string_to_quoted/2
    (archethic 1.0.8-rc1) lib/archethic/contracts/interpreter.ex:32: Archethic.Contracts.Interpreter.parse/1
    (archethic 1.0.8-rc1) lib/archethic/mining/pending_transaction_validation.ex:137: Archethic.Mining.PendingTransactionValidation.validate_contract/1
    (archethic 1.0.8-rc1) lib/archethic/mining/pending_transaction_validation.ex:55: Archethic.Mining.PendingTransactionValidation.validate/2
    (archethic 1.0.8-rc1) lib/archethic/mining/standalone_workflow.ex:118: Archethic.Mining.StandaloneWorkflow.handle_continue/2

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Manual test & unit test

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules