fix(files): make default explorer work with 'mini.pick'

Details:
- Picking a directory in 'mini.pick' (like in 'visit_paths` 'mini.extra'
  picker) is intended to execute `:edit <dir-path>`. With 'mini.files'
  enabled as default explorer, this throws an error when trying to
  delete a buffer.
  This happened because of the "smart delete buffer" logic in
  'mini.files' default explorer implementation. This commit adjusts the
  behavior and covers more use cases with tests.

Resolve #2156

Co-authored-by: Evgeni Chasnovski <[email protected]>

Author: abeldekat

lua/mini/files.lua

@@ -1382,7 +1382,11 @@ H.track_dir_edit = function(data)
   if vim.b.minifiles_processed_dir then
     -- Smartly delete directory buffer if already visited
     local alt_buf = vim.fn.bufnr('#')
-    if alt_buf ~= data.buf and vim.fn.buflisted(alt_buf) == 1 then vim.api.nvim_win_set_buf(0, alt_buf) end
+    -- - Setting alternative buffer is enough for the "directory buffer" to be
+    -- wiped out, as it has `bufhidden=wipe`. Forcing delete after showing alt
+    -- buffer might result in hard-to-track errors (like when opening directory
+    -- in 'mini.pick' when there is an altbuf for the buffer in target window).
+    if alt_buf ~= data.buf and vim.fn.buflisted(alt_buf) == 1 then return vim.api.nvim_win_set_buf(0, alt_buf) end
     return vim.api.nvim_buf_delete(data.buf, { force = true })
   end
 

tests/screenshots/tests-test_files.lua---Default-explorer---handles-close-without-opening-file

@@ -5769,15 +5769,37 @@ T['Default explorer']['works in `:tabfind .`'] = function()
 end
 
 T['Default explorer']['handles close without opening file'] = function()
+  local validate = function()
+    local buf_name = child.api.nvim_buf_get_name(0)
+    child.cmd('edit ' .. test_dir_path)
+    eq(is_explorer_active(), true)
+    close()
+    eq(is_explorer_active(), false)
+    eq(child.api.nvim_buf_get_name(0), buf_name)
+    eq(#child.api.nvim_list_bufs(), 1)
+  end
+
+  -- Should hide "directory buffer" if there is no alternative buffer
+  validate()
+
+  -- Should smartly (preserving layout) delete "directory buffer"
+  local win_id_other = child.api.nvim_get_current_win()
   child.cmd('wincmd v')
-  child.cmd('edit ' .. test_dir_path)
-  child.expect_screenshot()
+  local win_id = child.api.nvim_get_current_win()
+  local buf_id = child.api.nvim_get_current_buf()
 
-  -- Should close and smartly (preserving layout) delete "directory buffer"
-  close()
-  child.expect_screenshot()
-  eq(child.api.nvim_buf_get_name(0), '')
-  eq(#child.api.nvim_list_bufs(), 1)
+  eq(child.fn.win_findbuf(buf_id), { win_id, win_id_other })
+  validate()
+  eq(child.fn.win_findbuf(buf_id), { win_id, win_id_other })
+end
+
+T['Default explorer']['handles forcing other window as current'] = function()
+  child.cmd('edit ' .. test_file_path)
+  local init_win_id = child.api.nvim_get_current_win()
+
+  child.cmd('edit ' .. test_dir_path)
+  expect.no_error(function() child.api.nvim_set_current_win(init_win_id) end)
+  if child.fn.has('nvim-0.10') == 1 then eq(child.api.nvim_get_current_win(), init_win_id) end
 end
 
 return T

tests/screenshots/tests-test_files.lua---Default-explorer---handles-close-without-opening-file-002

@@ -2105,21 +2105,36 @@ T['default_choose()']['mimics empty buffer reuse'] = function()
 end
 
 T['default_choose()']['works for directory path'] = function()
-  local validate = function(item, path)
+  local validate = function(item, path, filetype)
     local buf_id_init = child.api.nvim_get_current_buf()
     default_choose(item)
 
     local buf_id_cur = child.api.nvim_get_current_buf()
-    eq(child.bo.filetype, 'netrw')
+    eq(child.bo.filetype, filetype)
     validate_buf_name(buf_id_init, path)
 
     -- Cleanup
     child.api.nvim_buf_delete(buf_id_init, { force = true })
     child.api.nvim_buf_delete(buf_id_cur, { force = true })
+
+    child.lua('if _G.MiniFiles ~= nil then _G.MiniFiles.close() end')
   end
 
-  validate(test_dir, test_dir)
-  validate({ text = test_dir, path = test_dir }, test_dir)
+  validate(test_dir, test_dir, 'netrw')
+  validate({ text = test_dir, path = test_dir }, test_dir, 'netrw')
+
+  -- Should work with 'mini.files' as default explorer
+  child.lua('require("mini.files").setup()')
+  validate(test_dir, test_dir, 'minifiles')
+  validate({ text = test_dir, path = test_dir }, test_dir, 'minifiles')
+
+  -- - Should work when there is an already opened file (matters in which code
+  --   path 'mini.files' takes when acting as a default explorer).
+  --   Earlier resulted in an outdated 'mini.pick' floating window.
+  child.cmd('edit ' .. real_file('a.lua'))
+  start_with_items({ test_dir })
+  type_keys('<CR>')
+  eq(#child.api.nvim_list_wins(), 2)
 end
 
 T['default_choose()']['works for buffer'] = function()