how does truffle decide when to update a contract?

Question

it has happened to me many times, that after updating a contract and running truffle migrate it simply told me network up to date

in order to reproduce the behaviour I did the following:

• create a folder metacoin
• run truffle unbox metacoin
• edit the truffle.js to include a testrpc node as the development network
• run testrpc
• run truffle migrate
• edit the file contracts/Metacoin.sol and adding a global public variable
• run truffle migrate again

I could verify that the address of the contract did not change. I know that I can force a deployment with --reset but this is not always a good option.

Answer 1

I don't have a proper answer. Many times it seems like it doesn't detect a file has changed and it will tell you its up to date.

Sometimes it doesn't say it's up to date but still the compilation and migration seem to be using old versions of the contract and I have to --reset.

Lately I find myself more and more having to also delete the build folder each time to make sure Its actually using the latest files.

Answer 2

I've had similar issues, even when I change code in the contracts.

Best solution is to rm -rf ./build folder, and then run truffle migrate.