c8 ignore next comment does not quite appropriately compensate for branches

[Trott]

• Version: v14.12.0
• Platform: macOS Darwin Kernel Version 19.6.0

Given this code in index.js:

function fn() {
  return true;
  /* c8 ignore next */
  console.log('never runs');
}

fn();

Running with ci node index.js, I get this output:

----------|---------|----------|---------|---------|-------------------
File      | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
----------|---------|----------|---------|---------|-------------------
All files |     100 |    66.67 |     100 |     100 |                   
 index.js |     100 |    66.67 |     100 |     100 | 2                 
----------|---------|----------|---------|---------|-------------------

I would expect the branches to all be considered covered since the entire uncovered branch is excluded by the c8 ignore comment.

----------|---------|----------|---------|---------|-------------------
File      | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
----------|---------|----------|---------|---------|-------------------
All files |     100 |    100 |     100 |     100 |                   
 index.js |     100 |    100 |     100 |     100 | 2                 
----------|---------|----------|---------|---------|-------------------

[Trott]

Even simpler reproduction:

return true;
/* c8 ignore next */
console.log('never runs');

[bcoe]

thanks @Trott 👍 will try to get to this in the not too distant future 🚀

[bcoe]

this should be fixed in c8@7.3.2.

[bcoe]

unfortunately this caused a regression with TypeScript, tldr; source maps are the worst.

[Trott]

unfortunately this caused a regression with TypeScript, tldr; source maps are the worst.

NOOOOOOOOoooooooooooo,,,,....!!!!!

[bcoe]

@Trott wow, it too me this long to get to this message in my inbox 😆

I have a cunning plan, I was thinking we could perhaps check if the covered range is only 1 character, at which point I think it's a good indicator I've detected a \n character.

I'll play with this soon.