Allow configuration of allowed_extensions for the migrations (fixes #1361)

[roderik]

• I added a separate config function to truffle-config, same naming and signature scheme as the test regexp
• I added the new config regexp as second choice to truffle-migrate. While there are no usages of the option version, I did not wan to inadvertently break any code depending on this option.
• separate commits because my editor wanted to reformat every line of code, yay prettier :)

[sneko]

@roderik after fixing what I mentioned in my comments I'm still getting errors due to TypeScript syntax.

Here one of my files:

var Migrations = artifacts.require("./Migrations.sol");

module.exports = async function(deployer, network, accounts) {
  await deployer.deploy(Migrations);
} as Truffle.Migration;

// because of https://stackoverflow.com/questions/40900791/cannot-redeclare-block-scoped-variable-in-unrelated-files
export {};

I get the following error when migrating:

} as Truffle.Migration;
  ^^

SyntaxError: Unexpected identifier

If I remove the as Truffle.Migration it shows me the next issue:

export {};
^^^^^^

SyntaxError: Unexpected token export
    at Object.createScript (vm.js:80:10)

To solve this my file needs to look like:

var Migrations = artifacts.require("./Migrations.sol");

module.exports = async function(deployer, network, accounts) {
  await deployer.deploy(Migrations);
};

Like an ES6 file...

Do you know why the parser is not using TypeScript?

Thanks,

[roderik]

@sneko, you are probably missing the require("ts-node/register"); line mentioned in the setup at https://github.com/ethereum-ts/truffle-typechain-example. Thanks for catching the missing require, forgot to copy paste that line in the commit :)

[sneko]

@roderik I’m actually requiring the tsnode/register... hmmm I don’t understand what could be the problem.

I’m using Truffle 5 and my settings are stored in the « truffle-config.js ».

I will try to figure out tomorrow morning what’s going on. (Including cloning and testing the example)

[sneko]

@roderik the truffle-typechain-example is working well for migrations if I build on my own truffle (including your PR).

But if I add this line in the truffle.js:
migrations_file_extension_regexp: /.*\.ts$/,

I get the same error than in my project:

} as Truffle.Migration;
  ^^

SyntaxError: Unexpected identifier

😢

[CruzMolina]

Thanks again for doing this @roderik. @sneko I did some playing around with replicating your error and I believe it is a configuration issue on the ts side (typechain, tsconfig, possibly truffle-typings).

Since this is a simple enough feature addition, I think we're going to move ahead with supporting this after I add some tests to ensure coverage.

[CruzMolina]

@sneko did a little more replication using the truffle-typechain-example repo.

I was able to get the example working using their current setup (package.json, tsconfig, etc). I was also able to get things working using Roderik's current workaround here.

[sneko]

@CruzMolina yeah the workaround is working.

But did you succeed in replicating the issue I get?

Building Truffle with this pull request and injecting it inside the node_modules directory on truffle-typechain-example (do not forget to add migrations_file_extension_regexp: /.*\.ts$/, inside the Truffle config file)

[CruzMolina]

Ah, I see what you mean @sneko. After reviewing the codebase, it looks like truffle-migrate exports the migration files to a js parser in truffle-require. For now using truffle-typings with typechain, you don't have to add to or change migrations_file_extension_regexp to parse .ts (tsc will transpile it for you to .js). I was able to get the example repo working without Roderik's workaround. You don't have to specify a different migrations_build folder, you can just use the given repo's tsconfig and the example migrations .ts file to base your own migration files.

[CruzMolina]

So after diving into this, it looks like this change doesn't immediately further .ts integration or ethereum-ts support (although #1385 should help a teeny bit towards that end). However, it does make an aspect of truffle-config configurable in a way that could be useful more long term.

[fainashalts]

+1 Looks good to me!