Custom .projectile in sub-dir does not work

[arichiardi]

Expected behavior

I have the following custom project type.

(projectile-register-project-type
 'custom (lambda (project-root) (and project-root (string-match "my-subproject/src/foo" project-root)))
 :project-file ".projectile"
 :test-suffix "_test"

The .projectile file lives in the foo subdir of src. I'd like to have custom has detected project type (and use the _test suffix).

Actual behavior

The project type is generic

Steps to reproduce the problem

Create a git repo with src/foo/.projectile in it. Register the above project.

Environment & Version information

Projectile version information

Projectile version: 2.8.0

I did a bit of debugging and it seems the following happens:

(if (functionp marker) ;; *correctly evaluates to true*
    ;; the below call with dir=nil returns falsey though
     (and (funcall marker dir) project-type)
            (and (projectile-verify-files marker dir) project-type))

Should my marker function return true if the input dir is nil?