Validate rule schemas

[fvictorio]

The schemas of the rules configurations now only represent the configuration itself (meaning, the second element of the array when setting a rule). Then, base-checker validates that the schema is correct. If it's not, only a warning is emitted, execution is not interrupted.

Lot of files to review here, but the important part is in base-checker.

[coveralls]

Coverage decreased (-0.3%) to 95.99% when pulling c2c1fb3 on validate-rule-schemas into e07b908 on 3.0.

[fernandomg]

@fvictorio, it would be nice to have the ajv validated scheme to inform which are those allowed values.

node solhint.js Foo.sol
[solhint] Warning: invalid configuration for rule 'max-line-length':
  should be equal to one of the allowed values
[solhint] Warning: rule 'avoid-sha3' level is 'eror'; should be one of "error", "warn" or "off"

the config file:

{
  "rules": {
    "avoid-sha3": "eror",
    "max-line-length": ["not-a-valid-value", 10],
    "avoid-throw": "error"
  }
}

what do you think?

[fvictorio]

In this particular case, we can do it "by hand": checking for the first element of the array the same way it's being done when the configuration is just a string (i.e., the level).

But this won't translate to rules that use the oneOf validator of ajv. But we could use better-ajv-errors for this.

[fernandomg]

I was thinking about using the params prop. https://ajv.js.org/#error-parameters

[fernandomg]

This works great.

Now I get the issue with oneOf.