dante-status being called thousands of times over a few seconds

[puffnfresh]

I sometimes open a new Haskell file outside of a project. When I do this Dante gets very slow and Emacs sits at about 100% CPU whenever I edit the buffer.

I found that Emacs supports profiling via (profiler-start) then I did a (profiler-report) to get:

- redisplay_internal (C function)                                7700  46%
 - eval                                                          7158  42%
  - spaceline-ml-main                                            6837  41%
   - mapcar                                                      6754  40%
    - #<compiled 0x24da0c3>                                      6751  40%
     - format-mode-line                                          6741  40%
      - eval                                                     6741  40%
       - concat                                                  6741  40%
        - dante-status                                           6741  40%
         - dante-state                                           4555  27%
          - dante-buffer-p                                       4555  27%
           - dante-buffer-name                                   4555  27%
            - dante-project-root                                 4555  27%
             - dante-cabal-find-file                             4553  27%
              - dante-cabal-find-pkg-desc                        4343  26%
               + directory-files                                 2516  15%
               + cl-remove-if-not                                   1   0%
              + file-attributes                                    19   0%
             + dante-buffer-file-name                               1   0%
         - dante-buffer-p                                        2186  13%
          + dante-buffer-name                                    2186  13%
     + s-trim                                                       2   0%

So I guess the root cause is that Dante is trying to get a .cabal file over and over and not finding one. Can we make Dante not spike to 100% whenever I edit a file without a .cabal project?

[puffnfresh]

echo > x.cabal

Is enough to make Dante start working. Doesn't even need content.

[puffnfresh]

Looks like we just need to set these fields so that Dante stops trying to populate them:

[jyp]

Nice report; I've cached dante-project-root, let me know if this fixes the problem.