Vertico taking several seconds to find file "~/", worse with Orderless

[breadsander]

Hi all,

Anytime I try to do a find-file to "~/" I get a substantial hang, on the order of 5 to 10 seconds. This hang was not present in Ivy/Counsel. My homedir is an NFS mount itself, and I've not had any issues with accessing the directory through other means. In fact, if I find-file to the homedir path, rather than use "~" it does not experience slowness.

Here's a profile without orderless. It is unclear exactly what is causing this.

         430 100% - command-execute
         430 100%  - funcall-interactively
         430 100%   - eval-last-sexp
         430 100%    - elisp--eval-last-sexp
         430 100%     - elisp--preceding-sexp
         430 100%      - forward-sexp
         430 100%       - scan-sexps
         430 100%        - debug
         428  99%         - recursive-edit
         269  62%          - command-execute
         265  61%           - byte-code
         159  36%            - read-extended-command
         159  36%             - read-extended-command-1
         159  36%              - completing-read-default
         159  36%               - apply
         159  36%                - vertico--advice
         159  36%                 - apply
         158  36%                  - #<subr completing-read-default>
         110  25%                   - vertico--exhibit
         106  24%                    - vertico--update
         106  24%                     - vertico--recompute
          52  12%                      - vertico--filter-completions
          52  12%                       - completion-all-completions
          52  12%                        - apply
          52  12%                         - #<subr completion-all-completions>
          52  12%                          - completion--nth-completion
          49  11%                           - completion--some
          49  11%                            - #<compiled -0x1c5e3c4fd04ed767>
          45  10%                             - completion-basic-all-completions
          45  10%                              - completion-pcm--all-completions
          45  10%                               - #<subr F616e6f6e796d6f75732d6c616d626461_anonymous_lambda_55>
          45  10%                                - complete-with-action
          16   3%                                 - all-completions
           8   1%                                  - #<compiled 0x495e228b6f5e655>
           4   0%                                     #<compiled 0x14d9b8e2954b496d>
           4   0%                             - completion-pcm-all-completions
           4   0%                                completion-pcm--find-all-completions
           3   0%                           - #<compiled -0x1dcb6e3381f58ee6>
           3   0%                            - completion--twq-all
           3   0%                             - #<compiled 0x19aa6882efeb3dc3>
           3   0%                              - minibuffer-maybe-quote-filename
           3   0%                                 file-local-name
          50  11%                      - completion-boundaries
          50  11%                       - read-file-name-internal
          50  11%                        - completion--some
          50  11%                         - #<compiled 0x14c4a92da5a52d92>
          50  11%                          - complete-with-action
          50  11%                           - completion--file-name-table
          50  11%                            - completion-boundaries
          50  11%                               completion-file-name-table
           4   0%                      - vertico-sort-history-length-alpha
           4   0%                         #<subr F616e6f6e796d6f75732d6c616d626461_anonymous_lambda_14>
           4   0%                      vertico--arrange-candidates
          22   5%                   - timer-event-handler
          22   5%                    + apply
         106  24%            - find-file-read-args
         106  24%             - read-file-name
         106  24%              - read-file-name-default
         106  24%               - completing-read-default
         106  24%                - apply
         106  24%                 - vertico--advice
         106  24%                  - apply
         103  23%                   - #<subr completing-read-default>
          61  14%                    - timer-event-handler
          61  14%                     - apply
          47  10%                      - auto-revert-buffers
          33   7%                         auto-revert--buffer-candidates
          14   3%                        #<subr F616e6f6e796d6f75732d6c616d626461_anonymous_lambda_11>
          16   3%                    - vertico--exhibit
          10   2%                     - vertico--update
          10   2%                        redisplay
           6   1%                     - vertico--arrange-candidates
           6   1%                      + vertico--affixate
           4   0%             funcall-interactively

Here's a profile with orderless, where it is substantially slower:

         973  99% - command-execute
         973  99%  - funcall-interactively
         973  99%   - eval-last-sexp
         973  99%    - elisp--eval-last-sexp
         973  99%     - elisp--preceding-sexp
         973  99%      - forward-sexp
         973  99%       - scan-sexps
         973  99%        - debug
         969  99%         - recursive-edit
         738  75%          - command-execute
         734  75%           - byte-code
         664  68%            - read-extended-command
         664  68%             - read-extended-command-1
         664  68%              - completing-read-default
         664  68%               - apply
         664  68%                - vertico--advice
         664  68%                 - apply
         656  67%                  - #<subr completing-read-default>
         569  58%                   - vertico--exhibit
         563  57%                    - vertico--update
         541  55%                     - vertico--recompute
         413  42%                      - vertico--filter-completions
         413  42%                       - completion-all-completions
         413  42%                        - apply
         413  42%                         - #<subr completion-all-completions>
         413  42%                          - completion--nth-completion
         413  42%                           - completion--some
         413  42%                            - #<compiled -0x1c58c4b7965ed767>
         341  34%                             - orderless-all-completions
         341  34%                              - orderless--filter
         341  34%                               - #<subr F616e6f6e796d6f75732d6c616d626461_anonymous_lambda_55>
         341  34%                                - complete-with-action
          36   3%                                 - all-completions
          20   2%                                  - #<compiled 0x495e228b6f5e655>
           8   0%                                   - #<compiled 0x14d05770554b496d>
           4   0%                                      command-completion-default-include-p
          60   6%                             - completion-pcm-all-completions
          60   6%                              - completion-pcm--find-all-completions
          60   6%                               - completion-boundaries
          60   6%                                  completion-file-name-table
          12   1%                             - completion-basic-all-completions
          12   1%                              - completion-pcm--all-completions
          12   1%                               - #<subr F616e6f6e796d6f75732d6c616d626461_anonymous_lambda_55>
          12   1%                                  complete-with-action
         120  12%                      - completion-boundaries
         120  12%                       - read-file-name-internal
         120  12%                        - completion--some
         120  12%                         - #<compiled 0x1c307d0699bf2d70>
         120  12%                          - complete-with-action
         120  12%                           - completion--file-name-table
         120  12%                            - completion-boundaries
         120  12%                               completion-file-name-table

Any help in analyzing these profiles for problems is greatly appreciated. Thank you!

[breadsander]

Okay, I've noticed that when profiling find-file for paths that do not include "~" that the read-extended-command function is not present. My hunch is that, for some reason, the "~" drives a read-extended-command and it's punishing on vertico.

[breadsander]

I believe this slowness is not a result of Veritco, but rather the ~ notation tries to iterate across all the users in the company via LDAP and automount. I am hoping someone here might be able to tell me how to prevent Vertico from automatically listing the directory contents under "~".

[minad]

You could try to write a custom completion style (wrapping Orderless) which recognizes the problematic input and returns an empty candidate list in this case. This will prevent the inefficiency. Check out the completion style documentation/implementations. The code at https://github.com/minad/vertico?tab=readme-ov-file#tramp-hostname-and-username-completion can get you started.

[breadsander]

Thank you @minad for taking the time to respond. I've taken a look at think I kind-of sort-of have a path forward but I'm hitting an obstacle.

So, from my reading, it seems like completion-category-overrides just sets those override in front of what's inside completion-styles. In my config that would be contains-tilde -> partial-completion -> orderless -> basic. So, I'm curious how writing a category override that returns an empty list wouldn't just eventually default down to orderless? My assumption is "empty" means try the next completion method. Here's my config:

    (defun contains-tilde-p (path)
      "Check if PATH contains a tilde (~)."
      (string-match-p "~" path))

    (defun contains-tilde-try-completion (string table pred point)
      (and (contains-tilde-p string)
           (completion-basic-try-completion string table pred point)))
    (defun contains-tilde-all-completions (string table pred point)
      (and (contains-tilde-p string)
           (completion-basic-all-completions string table pred point)))

     (add-to-list
     'completion-styles-alist
     '(contains-tilde contains-tilde-try-completion contains-tilde-all-completions nil))

    (setq completion-styles '(orderless basic)
          completion-category-defaults nil
          completion-category-overrides '((file (styles contains-tilde partial-completion))))

I don't intend to keep 'completion-basic-all-completions' there and instead I suppose I need to generate an empty list. My concern is, wouldn't an empty list coming out of 'contains-tilde' just result in partial-completion, then orderless, then basic (again) being tried?

I should mention that even 'basic' across everything still causes a significant lag. I think it's effectively the expansion of "~" triggering the automounter + READDIR that is very painful. I don't know if the completion framework is triggering a READDIR, or if the READDIR has to be done before the completion framework does its search. If it's the latter and this READDIR is fired regardless of the completion method then I think I might be in trouble either way.

[minad]

My assumption is "empty" means try the next completion method.

Yes. In order for this to work, there must only be a single completion style, or each of your styles which are tried must implement the check to return empty.