Don't remove cask directories when upgrading.

Fixes Homebrew/homebrew-cask#102721.

Library/Homebrew/cask/artifact/moved.rb

@@ -39,34 +39,45 @@ def move(adopt: false, force: false, verbose: false, command: nil, **options)
           raise CaskError, "It seems the #{self.class.english_name} source '#{source}' is not there."
         end
 
-        if Utils.path_occupied?(target)
-          if adopt
-            ohai "Adopting existing #{self.class.english_name} at '#{target}'"
-            same = command.run(
-              "/usr/bin/diff",
-              args:         ["--recursive", "--brief", source, target],
-              verbose:      verbose,
-              print_stdout: verbose,
-            ).success?
-
-            unless same
-              raise CaskError,
-                    "It seems the existing #{self.class.english_name} is different from " \
-                    "the one being installed."
+        if Utils.path_occupied?(target) && (!target.directory? || !target.children.empty? || !source.directory?)
+          if upgrade && target.directory? && target.children.empty?
+            # If the target is an empty directory, it was probably an upgrade that only removed directory contents.
+            unless source.directory?
+              if target.parent.writable? && !force
+                target.rmdir
+              else
+                Utils.gain_permissions_remove(target, command: command)
+              end
+            end
+          else
+            if adopt
+              ohai "Adopting existing #{self.class.english_name} at '#{target}'"
+              same = command.run(
+                "/usr/bin/diff",
+                args:         ["--recursive", "--brief", source, target],
+                verbose:      verbose,
+                print_stdout: verbose,
+              ).success?
+
+              unless same
+                raise CaskError,
+                      "It seems the existing #{self.class.english_name} is different from " \
+                      "the one being installed."
+              end
+
+              # Remove the source as we don't need to move it to the target location
+              source.rmtree
+
+              return post_move(command)
             end
 
-            # Remove the source as we don't need to move it to the target location
-            source.rmtree
+            message = "It seems there is already #{self.class.english_article} " \
+                      "#{self.class.english_name} at '#{target}'"
+            raise CaskError, "#{message}." unless force
 
-            return post_move(command)
+            opoo "#{message}; overwriting."
+            delete(target, force: force, command: command, **options)
           end
-
-          message = "It seems there is already #{self.class.english_article} " \
-                    "#{self.class.english_name} at '#{target}'"
-          raise CaskError, "#{message}." unless force
-
-          opoo "#{message}; overwriting."
-          delete(target, force: force, command: command, **options)
         end
 
         ohai "Moving #{self.class.english_name} '#{source.basename}' to '#{target}'"
@@ -79,7 +90,16 @@ def move(adopt: false, force: false, verbose: false, command: nil, **options)
           end
         end
 
-        if target.dirname.writable?
+        if target.directory?
+          if target.writable?
+            source.children.each { |child| FileUtils.move(child, target + child.basename) }
+          else
+            command.run!("/bin/cp", args: ["-pR", "#{source}/*", "#{source}/.*", "#{target}/"],
+                                    sudo: true)
+          end
+          # TODO: copy extended attributes
+          source.rmtree
+        elsif target.dirname.writable?
           FileUtils.move(source, target)
         else
           # default sudo user isn't necessarily able to write to Homebrew's locations
@@ -125,13 +145,23 @@ def move_back(skip: false, force: false, command: nil, **options)
         delete(target, force: force, command: command, **options)
       end
 
-      def delete(target, force: false, command: nil, **_)
+      def delete(target, force: false, upgrade: false, command: nil, **_)
         ohai "Removing #{self.class.english_name} '#{target}'"
         raise CaskError, "Cannot remove undeletable #{self.class.english_name}." if MacOS.undeletable?(target)
 
         return unless Utils.path_occupied?(target)
 
-        if target.parent.writable? && !force
+        if upgrade && target.directory?
+          # If an app folder is deleted, macOS considers the app uninstalled and removes some data.
+          # Remove only the contents to handle this case.
+          target.children.each do |child|
+            if target.writable? && !force
+              child.rmtree
+            else
+              Utils.gain_permissions_remove(child, command: command)
+            end
+          end
+          elif target.parent.writable? && !force
           target.rmtree
         else
           Utils.gain_permissions_remove(target, command: command)