Treemacs freezes sometimes when switching workspace (with a first project with a lot of files/directories) or when expanding a project/folder

[sebastiaanspeck]

I sometimes have my treemacs freezing, until I manually press C-g. It sometimes freezes when switching workspace or expanding a project/folder. After pressing C-g, treemacs just shows my switched workspace or expanded project/folder. It is pretty annoying that I sometimes need to manually stop treemacs (with C-g).

I can't find why it would freeze. I was able to fix one project/folder, since it contained a hierarchy of empty folders. A fix for switching my workspaces was to put a smaller project at the top and the project with a lot of files/folders as second.

I use treemacs 3.2 (but the issue also applies to the latest beta version):

(use-package treemacs
  :defer t
  :bind (("<f12>" . 'treemacs))
  :hook (emacs-startup . (lambda () (treemacs)))
  :custom
  (treemacs-no-png-images t)
  (treemacs-move-files-by-mouse-dragging nil)
  (treemacs-silent-refresh t)
  :config
  (use-package treemacs-magit
    :after magit)
  (setq treemacs-filewatch-mode (not (eq system-type 'windows-nt)))
  (add-to-list 'treemacs-pre-file-insert-predicates #'treemacs-is-file-git-ignored?)
  (when (executable-find "git")
    (treemacs-git-mode 'simple)))

A backtrace I could fetch (directories are pseudonymised):

Debugger entered--Lisp error: (quit)
  treemacs-find-file-node("D:/workspace/sebastiaan.speck/project/tests" #s(treemacs-project :name "tests" :path "D:/workspace/sebastiaan.speck/project" :path-status local-readable :is-disabled? nil))
  treemacs--flatten-dirs((("/path/to/dir" "D:/workspace/sebastiaan.speck/project/tests" "D:/workspace/sebastiaan.speck/project/tests/application_tests" "D:/workspace/sebastiaan.speck/project/tests/application_tests/resources" "D:/workspace/sebastiaan.speck/project/tests/application_tests/resources/base")))
  treemacs--expand-root-node(#<marker (moves after insertion) at 15 in  *Treemacs-Scoped-Buffer-#<frame *package update results* - GNU Emacs at rds 000001f25a600b40>*> nil)
  treemacs-toggle-node(nil)
  treemacs-TAB-action(nil)
  funcall-interactively(treemacs-TAB-action nil)
  command-execute(treemacs-TAB-action)

[Alexander-Miller]

The next time it happens run kill -12 on Emacs' PID. That will force it to stop and show a stack trace of what it's been up to.

Also, is this issue deterministic - does it always happen for specific projects and directories or does it pop up and go away randomly?

[sebastiaanspeck]

The next time it happens run kill -12 on Emacs' PID. That will force it to stop and show a stack trace of what it's been up to.

Will do

Also, is this issue deterministic - does it always happen for specific projects and directories or does it pop up and go away randomly?

I found one project/directory that had the issue and one workspace that had the issue. I solved both issues myself; the project/directory contained a hierarchy tree of empty folders (leftover after changing Git branches) and the workspace had a relatively large repository as first project (which is expanded on switching).

[Alexander-Miller]

If the first trace is anything to go by then there is a loop in the find file routine. That code is very old and battle-tested, it should not get stuck unless there is something wrong with treemacs' inner state.

If this function is the culprit then the next step will be to debug its inner workings with some print statements. Having a reproducible case would make that much easier.

[sebastiaanspeck]

A reproducible scenario I found out, in the root of a project create a hierarchy of directories that goes at least three levels deep (e.g. foo/bar/baz. Try opening that structure using TAB and it freezes. The second folder (bar in the example) just expands/collaps without any issues. Deleting the structure also causes it to freeze.

A repository that causes the workspace freeze: https://github.com/roadrunner1776/magik. It does not contain any three-level deep directories, so expanding/collapsing works without issues.

[sebastiaanspeck]

I might have an idea that it was related to using the Python-extras. It could be the case that my Python-installation is corrupted. I simply disabled it for now and will see if that resolves the issue completely.

Edit: that didn't solve it completely. The funny part is that during my session everything works fine until I one time had a freezing treemacs, then the treemacs freezes more often (even on folders that didn't freeze before).

[sebastiaanspeck]

The next time it happens run kill -12 on Emacs' PID. That will force it to stop and show a stack trace of what it's been up to.

I am working on Windows FYI :)

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