feat(buffer_previewer): expose scroll_fn()

lua/telescope/config.lua

@@ -930,6 +930,17 @@ append(
     Default: require("telescope.previewers").buffer_previewer_maker]]
 )
 
+append(
+  "buffer_scroll_fn",
+  function(...)
+    return require("telescope.previewers").buffer_scroll_fn(...)
+  end,
+  [[
+    Function pointer to the default scroll function in buffer previewers.
+
+    Default: require("telescope.previewers").buffer_scroll_fn]]
+)
+
 -- @param user_defaults table: a table where keys are the names of options,
 --    and values are the ones the user wants
 -- @param tele_defaults table: (optional) a table containing all of the defaults

lua/telescope/previewers/buffer_previewer.lua

@@ -307,7 +307,7 @@ local search_teardown = function(self)
   end
 end
 
-local scroll_fn = function(self, direction)
+previewers.scroll_fn = function(self, direction)
   if not self.state then
     return
   end
@@ -475,7 +475,7 @@ previewers.new_buffer_previewer = function(opts)
   end
 
   if not opts.scroll_fn then
-    opts.scroll_fn = scroll_fn
+    opts.scroll_fn = conf.buffer_scroll_fn
   end
 
   if not opts.scroll_horizontal_fn then

lua/telescope/previewers/init.lua

@@ -243,6 +243,9 @@ previewers.new_buffer_previewer = buffer_previewer.new_buffer_previewer
 ---@param opts table: keys: `use_ft_detect`, `bufname` and `callback`
 previewers.buffer_previewer_maker = buffer_previewer.file_maker
 
+--- A function to scroll the buffer of buffer previewers
+previewers.buffer_scroll_fn = buffer_previewer.scroll_fn
+
 --- A previewer that is used to display a file. It uses the `buffer_previewer`
 --- interface and won't jump to the line. To integrate this one into your
 --- own picker make sure that the field `path` or `filename` is set for