fix: don't take over the preview window until it's opened for oil (#532)

lua/oil/init.lua

@@ -454,7 +454,7 @@ M.open_preview = function(opts, callback)
     end
   end
 
-  local preview_win = util.get_preview_win()
+  local preview_win = util.get_preview_win({ include_not_owned = true })
   local prev_win = vim.api.nvim_get_current_win()
   local bufnr = vim.api.nvim_get_current_buf()
 
@@ -501,6 +501,7 @@ M.open_preview = function(opts, callback)
 
       preview_win = vim.api.nvim_open_win(bufnr, true, win_opts)
       vim.api.nvim_set_option_value("previewwindow", true, { scope = "local", win = preview_win })
+      vim.api.nvim_win_set_var(preview_win, "oil_preview", true)
       vim.api.nvim_set_current_win(prev_win)
     elseif vim.fn.has("nvim-0.9") == 1 then
       vim.api.nvim_win_set_config(preview_win, { title = entry_title })
@@ -568,6 +569,7 @@ M.open_preview = function(opts, callback)
     end
 
     vim.api.nvim_set_option_value("previewwindow", true, { scope = "local", win = 0 })
+    vim.api.nvim_win_set_var(0, "oil_preview", true)
     for k, v in pairs(config.preview_win.win_options) do
       vim.api.nvim_set_option_value(k, v, { scope = "local", win = preview_win })
     end

lua/oil/util.lua

@@ -668,10 +668,17 @@ M.hack_around_termopen_autocmd = function(prev_mode)
   end, 10)
 end
 
+---@param opts? {include_not_owned?: boolean}
 ---@return nil|integer
-M.get_preview_win = function()
+M.get_preview_win = function(opts)
+  opts = opts or {}
+
   for _, winid in ipairs(vim.api.nvim_tabpage_list_wins(0)) do
-    if vim.api.nvim_win_is_valid(winid) and vim.wo[winid].previewwindow then
+    if
+      vim.api.nvim_win_is_valid(winid)
+      and vim.wo[winid].previewwindow
+      and (opts.include_not_owned or vim.w[winid]["oil_preview"])
+    then
       return winid
     end
   end