Please check your gas amount : may be misleading

gistfile1.txt

I just started learning solidity development, and when I started writing my own Smart Contract - I came across this error.

Error encountered, bailing. Network state unknown. Review successful transactions manually.
Error: The contract code couldn't be stored, please check your gas amount.
truffle compile worked OK, but truffle migrate gave this error.

Usually, it is said that is there is a loop (infinite loop, due to logic error) one usually "runs out of gas"

If you purely look at the error, it seems "logical" i.e. there is no compilation error, but when deploying the smart contract you "ran out of gas"

But I was writing a really simple code - there were no loops.

Over the years, I have realized that sometimes, reviewing the code helps uncover the problem, so I did. Without looking for "loops" and such, and realized that the problem was not really runtime error.

In my opinion, this should have been caught at compile time.

To understand what was the problem, let's see some code

One thing different from usual "hello world" code was that I had two classes.

contract Animal {
    uint256 public weight;
    function name() public view returns (string);
}
and

contract Dog is Animal {
   ....
   ....
   ....
}
Obviously Animal is an interface, and method name() must be implemented by Dog

It is obvious looking back.

But when you are shown an error "please check your gas amount" - you may be thrown off guard.

Once I added the missing method, the error went away.

I understand solidity is a new language, and the ecosystem is yet maturing. I'm sure, eventually the error messages will become more clearer/precise or just overall "better"

In the mean time, Review your code without any bias, and you may just find the solution.

ref: https://mandarvaze.bitbucket.io/posts/please-check-your-gas-amount-maybe-misleading.html#.WozcCRNua_g