xref-js2 false-positive checks keeps all checked buffer files open

[mohkale]

this is the code block in question.

(defun xref-js2--false-positive (candidate)
  "Return non-nil if CANDIDATE is a false positive.
Filtering is done using the AST from js2-mode."
  (let* ((file (map-elt candidate 'file))
         (buffer-open (get-file-buffer file)))
    (prog1
        (with-current-buffer (find-file-noselect file t)
          (save-excursion
            (save-restriction
              (widen)
              (unless (or (eq major-mode 'js2-mode)
                          (seq-contains (map-keys minor-mode-alist) 'js2-minor-mode))
                (js2-minor-mode 1))
              (goto-char (point-min))
              (forward-line (1- (map-elt candidate 'line)))
              (search-forward (map-elt candidate 'symbol) nil t)
              ;; js2-mode fails to parse the AST for some minified files
              (ignore-errors
                (let ((node (js2-node-at-point)))
                  (or (js2-string-node-p node)
                      (js2-comment-node-p node))))))))))

there's a get-file-buffer call in the let clause, but the evaluated variable is never used. the body is also wrapped in a prog1 despite not needing to be. Both these reasons lead me to conclude the that after the false-positive-check buffer-open was supposed to be used to check whether the opened buffer should be killed or not (killed if the corresponding file wasn't already open). For one reason or another it was either never implemented or deprecated in favor of the current solution. Regardless, for large projects (and over controlling weirdos like myself 😈) having so many open buffers is inconvenient.

[mohkale]

Okay. I tried finding a way to close it, but noticed a steep drop off in response speed. using profiler, it seems that my projectile hook is slowing down the file opening time for every file, which for large projects makes it feel like it's taking ages (takes upto 5 minutes the first time). After being opened once it's noticably faster tho. I guess, closing the open buffers impairs the usability of this plugin. What a shame, I guess I'll have to only use xref-js2 in essential situations or maybe find a way to disable any hooks for js2 mode when used with this plugin.

[NicolasPetton]

MoHKale <notifications@github.com> writes:

Okay. I tried finding a way to close it, but noticed a steep drop off in response speed. using profiler, it seems that my projectile hook is slowing down the file opening time for every file, which for large projects makes it feel like it's taking ages (takes upto 5 minutes the first time). After being opened once it's noticably faster tho. I guess, closing the open buffers impairs the usability of this plugin. What a shame, I guess I'll have to only use xref-js2 in essential situations or maybe find a way to disable any hooks for js2 mode when used with this plugin.

Could we find the files literally to keep things fast and then kill those buffers? Nico

[mohkale]

That seems reasonable obvious, why didn't I think of that? 😭😭😭 I'm working on some other stuff at the moment, but when I get a chance I'll try to implement and see how it works. Thnx.