Set projectile-auto-discover to nil by default

That's a safer default, given the changes to its behavior in 2.9.

Author: bbatsov

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## master (unreleased)
 
+### Changes
+
+* Set `projectile-auto-discover` to `nil` by default.
+
 ## 2.9.1 (2025-02-13)
 
 ### Bugs Fixed

doc/modules/ROOT/pages/usage.adoc

@@ -66,9 +66,17 @@ Recursive discovery is configured by specifying the search depth in a cons cell:
 (setq projectile-project-search-path '("~/projects/" "~/work/" ("~/github" . 1)))
 ----
 
-You can suppress the auto-discovery of projects on startup by setting
-`projectile-auto-discover` to `nil`. You can manually trigger the project
-discovery using `M-x projectile-discover-projects-in-search-path`.
+You can manually trigger the project
+discovery using `M-x projectile-discover-projects-in-search-path` or you can
+use `projectile-auto-discover` to discover projects on the search path automatically:
+
+[source,elisp]
+----
+(setq projectile-auto-discover t)
+----
+
+NOTE: Keep in mind the auto-discovery will be triggered every time you switch projects,
+so it's probably not a good idea if you have many projects on your search path.
 
 === Removal of missing projects
 

projectile.el

@@ -191,7 +191,7 @@ A value of nil means the cache never expires."
   :type '(choice (const :tag "Disabled" nil)
                  (integer :tag "Seconds")))
 
-(defcustom projectile-auto-discover t
+(defcustom projectile-auto-discover nil
   "Whether to discover projects when project switching commands are invoked.
 
 See also `projectile-project-search-path'."