TypeError: Cannot convert undefined or null to object
at Function.keys (<anonymous>)
at supplier.load.then.solc (/usr/local/lib/node_modules/truffle/build/webpack:/packages/truffle-compile/index.js:184:1)
at <anonymous>
Truffle v5.0.5 (core: 5.0.5)
Node v8.11.1
Bizarre, there may be something wrong going on with your truffle setup. By the way, the command you should be running is truffle migrate --network ropsten, not truffle migrate --ropsten.
I’m not sure, I believe it may be related to using a websocket provider. Sadly this seems to be caused by either web3 or truffle, so you’ll have better luck asking them
ropsten: {
network_id: 3,
host: "localhost",
port: 8545,
gas: 2900000
},
Your truffle configuration, truffle-config.js, includes the following object. This just says that under the tag ropsten truffle should deploy to localhost at port 8545. This is the address of your local ganache/testRPC instance.
To fix this problem just read this:
https://medium.com/coinmonks/5-minute-guide-to-deploying-smart-contracts-with-truffle-and-ropsten-b3e30d5ee1e
So you may need an infura account, and ethers for ropsten.