Phabricator linter can't find any lintable paths

Question

How can I configure phabricator to lint only files that match *py?

The following is my .arclint file:

{
  "linters": {
    "pylint": {
      "type": "pylint",
      "include": "(\\.py$)"
    }
  }
}

which is based heavily on the examples found here: https://secure.phabricator.com/book/phabricator/article/arcanist_lint/

When I run it I get this:

$ arc lint 
No paths are lintable.

If I remove the include line it tries to lint every file, so it must be something wrong with the regular expression: "(\\.py$)" which to be honest looks weird to me but is exactly what I found in the examples. And "(*.py)", "*.py", and "^*.py$" are all invalid regular expressions.

Answer 1

So it turns out there's actually nothing wrong with the regular expression. I'm just not using arc lint correctly.

The arc lint command only tries to lint files that have been modified. I was just expecting it to behave like arc lint --everything.

$ arc lint --help

  lint [options] [paths]
  lint [options] --rev [rev]
      Supports: git, svn, hg
      Run static analysis on changes to check for mistakes. If no files
      are specified, lint will be run on all files which have been modified.