require-valid-file-annotation is too aggressive

[wagerfield]

When configuring flowtype/require-valid-file-annotation like so:

"flowtype/require-valid-file-annotation": [ "error", "never" ]

I am getting the linting errors:

1/2 Flow file annotation not at the top of the file. (flowtype/require-valid-file-annotation)
2/2 Malformed Flow file annotation. (flowtype/require-valid-file-annotation)

I am experiencing this linting error inside a JS file that contain a bunch of eslint rule configurations that I have annotated with @fixable (for rules that are fixable) inside a JSDoc block comment (I appreciate this isn't an official JSDoc type annotation):

Looking at the rule implementation, I can see that the potentialFlowFileAnnotation boolean uses looksLikeFlowFileAnnotation to conditionally report errors.

To my mind, this test is a little aggressive since it just looks for comments starting @f (which @fixable obviously passes). I see that you have a utility function fuzzyStringMatch—could this not be used to increase the certainty that the comment is a @flow annotation instead of the @f regex?

[danharper]

Does the file have a @flow pragma? Looks like it could produce a better error message, though.

[wagerfield]

This file doesn't have the @flow pragma, no.

Since I am using flowtype throughout my project, I have configured my .eslintrc.js file like so:

module.exports = {
  settings: {
    flowtype: {
      onlyFilesWithFlowAnnotation: false
    }
  },
  plugins: [
    'flowtype'
  ]
  ...
}

Thus, I have configured "flowtype/require-valid-file-annotation": [ "error", "never" ] because I am enforcing the use of flowtype throughout my project with the above setting.