Output a JSON file that includes the list of files found in LintResult

[TamiTakamiya]

Dear ansible-lint team,

ansible-lint internally stores the information about the result of linting in the LintResult object.
LintResult has two sections; matches and files. ansible-lint's various format options (-f {brief,full,md,json,codeclimate,quiet,pep8,sarif}) work for the matches section, which contains lint issues found, but there seems no option available to print the information stored in the files section.

The files section is the list of Lintable objects, which include valuable information such as role, kind (file types defined in config.py), exc (exception thrown while processing), etc. We would like utilize such information in our code.

The output does not need to contain all information stored in Lintable objects, but needs to contain
the all files used as the source for the lint run.

Also we want to have the output for matches at the same time. If it can be invoked with the --sarif-file option

$ ansible-lint --sarif-file sarif.json --file-list filelist.json

and generate two JSON files, it would be ideal.

We wrote a PoC and following is the class we are using for converting a Lintable to a serializable object:

class LintableDict(dict):
    def __init__(self, lintable: Lintable):
        self['base_kind'] = str(lintable.base_kind)
        self['dir'] = str(lintable.dir)
        self['exc'] = None if lintable.exc is None else str(lintable.exc)
        self['filename'] = str(lintable.filename)
        self['kind'] = str(lintable.kind)
        self['name'] = str(lintable.name)
        self['parent'] = None if lintable.parent is None else str(lintable.parent.name)
        self['role'] = str(lintable.role)
        self['stop_processing'] = bool(lintable.stop_processing)
        self['updated'] = bool(lintable.updated)

and an example looks like

{
  "base_kind": "text/yaml",
  "dir": "/mnt/input/roles/delete_compute_node/tasks",
  "exc": null,
  "filename": "roles/delete_compute_node/tasks/main.yaml",
  "kind": "tasks",
  "name": "roles/delete_compute_node/tasks/main.yaml",
  "parent": "roles/delete_compute_node",
  "role": "delete_compute_node",
  "stop_processing": false,
  "updated": false
}

I do not think these changes are technically difficult, but there would be some considerations necessary for keeping consistency with existing ansible-lint features, serviceability, etc.

Thank you for reading this to the end!