deployer.exec command produces error during migration

Issue

Running truffle migrate produces error

Steps to reproduce

1. Create a script according to https://truffle.readthedocs.io/en/latest/getting_started/scripts/
2. Add deployer.exec command to migration jobs

module.exports = function(deployer) {
  deployer.exec('path/to/script');
}

1. Run truffle migrate

Expected behavior

Script runs and exits successfully

Actual behavior

Error encountered, bailing. Network state unknown. Review successful transactions manually.
Error: Expected parameter 'contracts_build_directory' not passed to function.
    at /Users/teddy/Projects/btl/truffle-webpack-demo-clone/node_modules/truffle/lib/expect.js:5:15
    at Array.forEach (native)
    at Object.options (/Users/teddy/Projects/btl/truffle-webpack-demo-clone/node_modules/truffle/lib/expect.js:3:19)
    at Object.exec (/Users/teddy/Projects/btl/truffle-webpack-demo-clone/node_modules/truffle/lib/require.js:89:12)
    at /Users/teddy/Projects/btl/truffle-webpack-demo-clone/node_modules/truffle/lib/deployer.js:101:17
    at /Users/teddy/Projects/btl/truffle-webpack-demo-clone/node_modules/truffle/lib/deployer.js:100:14
    at /Users/teddy/Projects/btl/truffle-webpack-demo-clone/node_modules/truffle/lib/deferredchain.js:20:15

Environment

• Truffle 2.1.1
• Node 7.0.0
• TestRPC 3.0.0
• macOS Sierra
• npm 3.10.8

[KeepMovingNo1]

Error: Invalid JSON RPC response: “” at Object.InvalidResponse (/usr/local/node/lib/node_modules/truffle/node_modules/web3/lib/web3/errors.js:35:16) at XMLHttpRequest.request.onreadystatechange (/usr/local/node/lib/node_modules/truffle/node_modules/web3/lib/web3/httpprovider.js:115:32) at XMLHttpRequestEventTarget.dispatchEvent (/usr/local/node/lib/node_modules/truffle/node_modules/xhr2/lib/xhr2.js:64:18) at XMLHttpRequest._setReadyState (/usr/local/node/lib/node_modules/truffle/node_modules/xhr2/lib/xhr2.js:354:12) at XMLHttpRequest._onHttpRequestError (/usr/local/node/lib/node_modules/truffle/node_modules/xhr2/lib/xhr2.js:544:12) at ClientRequest.<anonymous> (/usr/local/node/lib/node_modules/truffle/node_modules/xhr2/lib/xhr2.js:414:24) at emitOne (events.js:96:13) at ClientRequest.emit (events.js:188:7) at Socket.socketErrorListener (_http_client.js:309:9) at emitOne (events.js:96:13)

[tcoulter]

The deployer.exec() command is no longer available in Truffle 4.0 due to complexities in implementation. You can get around this by writing a module that accepts the deployer and associated contract abstractions as input to a function, and then importing that module into your migrations.

Closing this ticket for housekeeping. Please open a ticket if you run into any more issues. Thanks!