feat(pick): allow source.preview to set another buffer in main window

Author: echasnovski

CHANGELOG.md

@@ -16,6 +16,12 @@ There are following change types:
 
     The previous "reset by explicitly setting initial background color" behavior is available by setting the new `opts.explicit_reset` option to `true`.
 
+## mini.pick
+
+### Expand
+
+- Allow `source.preview` to directly set another buffer into picker's main window. The recommended way is still to adjust the provided `buf_id` buffer, but there is now a workaround if this is not reasonably possible.
+
 
 # Version 0.17.0
 

doc/mini-pick.txt

@@ -393,7 +393,9 @@ It will be called with the following arguments:
   of item previewing new scratch buffer is be created.
 - `item` - item to preview.
 
-It should update buffer `buf_id` to visually represent `item`.
+It should update buffer `buf_id` to visually represent `item`. It can also
+directly set another buffer in picker's main window, but usually it is more
+robust to update given `buf_id` directly.
 
 Example: >lua
 

lua/mini/pick.lua

@@ -388,7 +388,9 @@
 ---   of item previewing new scratch buffer is be created.
 --- - `item` - item to preview.
 ---
---- It should update buffer `buf_id` to visually represent `item`.
+--- It should update buffer `buf_id` to visually represent `item`. It can also
+--- directly set another buffer in picker's main window, but usually it is more
+--- robust to update given `buf_id` directly.
 ---
 --- Example: >lua
 ---
@@ -2959,7 +2961,7 @@ H.picker_show_preview = function(picker)
   vim.bo[buf_id].bufhidden = 'wipe'
   H.set_winbuf(win_id, buf_id)
   preview(buf_id, item)
-  picker.buffers.preview = buf_id
+  picker.buffers.preview = vim.api.nvim_win_get_buf(win_id)
   picker.view_state = 'preview'
 end
 

tests/test_pick.lua

@@ -3350,6 +3350,13 @@ T['builtin.help()']['works when help window is already opened'] = function()
   eq(#child.api.nvim_list_wins(), 2)
 end
 
+T['builtin.help()']['keeps correct picker state'] = function()
+  builtin_help()
+  type_keys('<Tab>')
+  local state = get_picker_state()
+  eq(child.api.nvim_win_get_buf(state.windows.main), state.buffers.preview)
+end
+
 T['builtin.help()']['can be properly aborted'] = function()
   builtin_help()
   type_keys('<C-c>')
@@ -5514,6 +5521,26 @@ T['Preview']['supports vertical and horizontal scroll'] = function()
   validate('<C-b>')
 end
 
+T['Preview']['handles `source.preview` setting buffer directly'] = function()
+  local buf_id_other = child.lua([[
+    _G.buf_id_other = vim.api.nvim_create_buf(false, true)
+    return _G.buf_id_other
+  ]])
+  child.api.nvim_buf_set_lines(buf_id_other, 0, -1, false, { 'Other preview buffer' })
+  child.lua_notify([[
+    local preview = function()
+      local state = MiniPick.get_picker_state()
+      vim.api.nvim_win_set_buf(state.windows.main, buf_id_other)
+    end
+    MiniPick.start({ source = { items = { 'a' }, name = 'Preview other', preview = preview } })
+  ]])
+  type_keys('<Tab>')
+
+  local state = get_picker_state()
+  eq(state.buffers.preview, buf_id_other)
+  eq(child.api.nvim_win_get_buf(state.windows.main), buf_id_other)
+end
+
 T['Matching'] = new_set()
 
 local start_with_items_matchlog = function(items)