counsel-projectile-switch-project with find-file action is slower than counsel-projectile-find-file

[rdeterre]

Hello 👋

On my system, running counsel-projectile-switch-project with the find-file action is much slower that calling counsel-projectile-find-file directly. This issue may be related to #153.

I used etrace to inspect function calls when running counsel-projectile-switch-project with the find-file action, and found that counsel-projectile--project-buffers-and-files is called a lot (22 times during my test).

As a quick test, I applied the patch below. With that change, counsel-projectile-switch-project is as fast as calling counsel-projectile-find-file directly.

diff --git a/counsel-projectile.el b/counsel-projectile.el
index 81b6b01..72e6944 100644
--- a/counsel-projectile.el
+++ b/counsel-projectile.el
@@ -1625,17 +1625,18 @@ candidate non-visited file."
            (not (projectile-project-p)))
       (counsel-projectile-action-switch-project)
     (projectile-maybe-invalidate-cache arg)
-    (ivy-read (projectile-prepend-project-name "Load buffer or file: ")
+    (let ((buffers-and-files (counsel-projectile--project-buffers-and-files)))
+      (ivy-read (projectile-prepend-project-name "Load buffer or file: ")
               ;; We use a collection function so that it is called each
               ;; time the `ivy-state' is reset. This is needed for the
               ;; "kill buffer" action.
-              #'counsel-projectile--project-buffers-and-files
+              buffers-and-files
               :matcher #'counsel-projectile--matcher
               :require-match t
               :action counsel-projectile-action
               :keymap counsel-projectile-map
               :extra-props (list :from-buffer from-buffer)
-              :caller 'counsel-projectile)))
+              :caller 'counsel-projectile))))
 
 (ivy-configure 'counsel-projectile
 :display-transformer-fn #'counsel-projectile-transformer
-- 

I'm sure there are edge cases that make it so that this cannot be applied directly but hopefully it can help :)