Projectile detecting sub-projects, update-project-type doesn't seem to work

[eviefp]

This is all happening in a cloned git repo, it's detecting "emacs" as a project in "./foo/emacs/*" because there's a default.nix there, and it seems to be discovering the project as a nix project.

The most obvious problem is when trying to use projectile-find-file, it only looks in path/to/project/foo/emacs rather than path/to/project. If I add a .projectile file in path/to/project, that fixes it, but I'd rather not do that.

So I tried adding a projectile-update-project-type (this is the whole use-package section for completeness):

(use-package projectile
  :ensure t
  :init
    (setq-default projectile-mode-line-prefix " Proj")
    (setq-default projectile-generic-command "rg --files --hidden -0")
    (setq projectile-project-search-path
          '("~/code/"
            "~/code/oss/"))
  :config
    (evil-define-key 'normal projectile-mode-map (kbd "SPC p") 'projectile-command-map)
    ; this uses "default.nix" files as the marker, which is wrong in larger/non-trivial nix projects,
    ; including my own nixfiles, so yeah. no thanks
    (projectile-update-project-type 'nix :project-file nil :marker-files nil :precedence 'low)

  :hook
    (after-init-hook . projectile-mode))

However, it's still not working despite me doing a clear project cache. The project-types variable also seems to show that the nix project is empty.

Alternatively, is there a setting I'm missing that makes "git repo root" as the highest precedence/override for project root? I'd rather do that.

[bbatsov]

This should be fixed on master by #2007 - the default is back to the git repo root winning over a nested manifest like default.nix, so you shouldn't need a .projectile file or to disable the nix type. Mind giving master a try?

[bbatsov]

Dug into this a bit more. Turns out (projectile-update-project-type 'nix :marker-files nil) couldn't have worked - an empty marker list matches every project rather than none, so that was quietly making things worse. #2009 fixes that and adds projectile-remove-project-type, which is the clean way to drop a mis-firing type:

(projectile-remove-project-type 'nix)

The git-root-wins default from #2007 should already handle your case on master without needing to touch the nix type at all, but the removal command is there if you want it.