modifiers should generate branches checks on all place they are used

[wighawag]

Currently modifiers are considered individually and not as part of where they are called
this cause coverage to wrongly assume the modifier code has been called on all branches simply because if it was executed in another context

solidity-coverage should copy-paste the modifier code and generate branching check on that resulting code.

For now, the only workaround is to not use modifier and instead copy the modifier code in place.

for example:

function transferOwnership(address newOwner) external onlyOwner {
  emit OwnershipTransferred(owner, newOwner);
  owner = newOwner;
}

function setFee(uint256 fee) external onlyOwner {
  _fee = fee;
}

modifier onlyOwner() {
  require(msg.sender == owner, "NOT_AUTHORIZED");
  _;
}

will generate 100% coverage of branches even if only the following test are executed

• transferOwnership from owner
• setFee from owner
• setFee from non-owner

the missing test for "transferOwnership from non-owner" will not be seen by the coverage.

On the contrary the following code will correctly trigger solidity-coverage to see less than 100% coverage as the require(... branching will be detected

function transferOwnership(address newOwner) external {
  require(msg.sender == owner, "NOT_AUTHORIZED");
  emit OwnershipTransferred(owner, newOwner);
  owner = newOwner;
}
function setFee(uint256 fee) external  {
  require(msg.sender == owner, "NOT_AUTHORIZED");
  _fee = fee;
}

[cgewecke]

@wighawag Yes!

There is an 0.8.x beta which addresses this issue. See this release note.

It was published at the beginning of January so there are some more recent bug fixes missing - I think it's equivalent to 0.7.13.

Do you have any interest in trying it out? Would love some real-world feedback about whether or not things work.

[wighawag]

Cool, I tried to find existing issue, but could not find (I think I was search for "modifiers" with a "s" :)
This is a duplicate of : #286
I ll close and I ll happily try the beta when I find some time. I ll report back