feat: welcome page + fix stale diff panes after git operations

VERSION

@@ -1 +1 @@
-2.41.1
+2.42.0

lua/codediff/ui/core.lua

@@ -364,8 +364,14 @@ function M.render_diff(left_bufnr, right_bufnr, original_lines, modified_lines,
   end
 
   -- Render moved code indicators (separate module)
-  local move = require("codediff.ui.move")
-  move.render_moves(left_bufnr, right_bufnr, lines_diff)
+  if lines_diff.moves and #lines_diff.moves > 0 then
+    local ok, move = pcall(require, "codediff.ui.move")
+    if ok and move then
+      move.render_moves(left_bufnr, right_bufnr, lines_diff)
+    else
+      vim.notify_once("[codediff] failed to load codediff.ui.move: " .. tostring(move), vim.log.levels.WARN)
+    end
+  end
 
   return {
     left_fillers = total_left_fillers,

lua/codediff/ui/explorer/refresh.lua

@@ -3,6 +3,7 @@ local M = {}
 
 local config = require("codediff.config")
 local tree_module = require("codediff.ui.explorer.tree")
+local welcome = require("codediff.ui.welcome")
 
 -- Setup auto-refresh triggers for explorer
 -- Returns a cleanup function that should be called when the explorer is destroyed
@@ -252,16 +253,95 @@ function M.refresh(explorer)
       -- Update status result for file selection logic
       explorer.status_result = status_result
 
-      -- Try to restore selection
-      if current_path then
-        local nodes = explorer.tree:get_nodes()
-        for _, node in ipairs(nodes) do
-          if node.data and node.data.path == current_path then
-            explorer.tree:set_node(node:get_id())
-            break
+      local function clear_current_file()
+        explorer.current_file_path = nil
+        explorer.current_file_group = nil
+      end
+
+      -- Helper: show the welcome page in the diff panes
+      local function show_welcome_page()
+        local lifecycle = require("codediff.ui.lifecycle")
+        local session = lifecycle.get_session(explorer.tabpage)
+        if session and not welcome.is_welcome_buffer(session.modified_bufnr) then
+          local mod_win = session.modified_win
+          if mod_win and vim.api.nvim_win_is_valid(mod_win) then
+            if session.layout == "inline" then
+              local w = vim.api.nvim_win_get_width(mod_win)
+              local h = vim.api.nvim_win_get_height(mod_win)
+              local welcome_buf = welcome.create_buffer(w, h)
+              require("codediff.ui.view.inline_view").show_welcome(explorer.tabpage, welcome_buf)
+            else
+              local orig_win = session.original_win
+              if orig_win and vim.api.nvim_win_is_valid(orig_win) then
+                local w = vim.api.nvim_win_get_width(orig_win) + vim.api.nvim_win_get_width(mod_win) + 1
+                local h = vim.api.nvim_win_get_height(orig_win)
+                local welcome_buf = welcome.create_buffer(w, h)
+                require("codediff.ui.view.side_by_side").show_welcome(explorer.tabpage, welcome_buf)
+              end
+            end
           end
         end
       end
+
+      -- Show welcome page when all files are clean
+      local total_files = #(status_result.unstaged or {}) + #(status_result.staged or {}) + #(status_result.conflicts or {})
+      if total_files == 0 then
+        clear_current_file()
+        show_welcome_page()
+      end
+
+      -- Re-select the currently viewed file after refresh.
+      -- Search all file children across all groups for the current file.
+      -- If found (possibly in a new group), call on_file_select to update diff panes.
+      -- If not found (committed/removed), show welcome page.
+      if explorer.current_file_path and total_files > 0 then
+        local found_file = nil
+        local found_group = nil
+        -- Search helper: look in a specific status list
+        local function search_group(files, group_name)
+          for _, f in ipairs(files or {}) do
+            if f.path == explorer.current_file_path then
+              return f, group_name
+            end
+          end
+          return nil, nil
+        end
+        -- Search same group first (preferred — e.g. hunk staging keeps file in same group)
+        local current_group = explorer.current_file_group
+        if current_group then
+          local group_lists = {
+            unstaged = status_result.unstaged,
+            staged = status_result.staged,
+            conflicts = status_result.conflicts,
+          }
+          found_file, found_group = search_group(group_lists[current_group], current_group)
+        end
+        -- If not in same group, search all groups
+        if not found_file then
+          found_file, found_group = search_group(status_result.conflicts, "conflicts")
+        end
+        if not found_file then
+          found_file, found_group = search_group(status_result.unstaged, "unstaged")
+        end
+        if not found_file then
+          found_file, found_group = search_group(status_result.staged, "staged")
+        end
+
+        if found_file then
+          -- File still exists (possibly in a new group) — re-select it
+          explorer.on_file_select({
+            path = found_file.path,
+            old_path = found_file.old_path,
+            status = found_file.status,
+            git_root = explorer.git_root,
+            group = found_group,
+          })
+        else
+          -- File was committed/removed — show welcome
+          clear_current_file()
+          show_welcome_page()
+        end
+      end
     end)
   end
 

lua/codediff/ui/lifecycle/cleanup.lua

@@ -4,6 +4,7 @@ local M = {}
 local accessors = require("codediff.ui.lifecycle.accessors")
 local session = require("codediff.ui.lifecycle.session")
 local state = require("codediff.ui.lifecycle.state")
+local welcome_window = require("codediff.ui.view.welcome_window")
 
 -- Autocmd group for cleanup
 local augroup = vim.api.nvim_create_augroup("codediff_lifecycle", { clear = true })
@@ -92,9 +93,11 @@ local function cleanup_diff(tabpage)
 
   -- Clear window variables if windows still exist
   if vim.api.nvim_win_is_valid(diff.original_win) then
+    welcome_window.apply_normal(diff.original_win)
     vim.w[diff.original_win].codediff_restore = nil
   end
   if vim.api.nvim_win_is_valid(diff.modified_win) then
+    welcome_window.apply_normal(diff.modified_win)
     vim.w[diff.modified_win].codediff_restore = nil
   end
 

lua/codediff/ui/lifecycle/session.lua

@@ -5,6 +5,7 @@ local M = {}
 local config = require("codediff.config")
 local virtual_file = require("codediff.core.virtual_file")
 local accessors = require("codediff.ui.lifecycle.accessors")
+local welcome_window = require("codediff.ui.view.welcome_window")
 
 -- Track active diff sessions
 -- Structure: {
@@ -110,6 +111,8 @@ function M.create_session(
     reapply_keymaps = reapply_keymaps,
   }
 
+  welcome_window.capture_session_profiles(active_diffs[tabpage])
+
   -- Mark windows with restore flag
   vim.w[original_win].codediff_restore = 1
   vim.w[modified_win].codediff_restore = 1
@@ -141,29 +144,33 @@ function M.create_session(
   end
 
   -- Force disable winbar to prevent alignment issues (except in conflict mode)
-  local function ensure_no_winbar()
-    local sess = active_diffs[tabpage]
+  local function sync_window_ui(sess, win)
     -- In conflict mode, preserve existing winbar titles (set by conflict_window.lua)
     if sess and sess.result_win and vim.api.nvim_win_is_valid(sess.result_win) then
       return
     end
     -- Normal diff mode: disable winbar
-    if vim.api.nvim_win_is_valid(original_win) then
-      vim.wo[original_win].winbar = ""
+    if sess and vim.api.nvim_win_is_valid(sess.original_win) then
+      vim.wo[sess.original_win].winbar = ""
     end
-    if vim.api.nvim_win_is_valid(modified_win) then
-      vim.wo[modified_win].winbar = ""
+    if sess and vim.api.nvim_win_is_valid(sess.modified_win) then
+      vim.wo[sess.modified_win].winbar = ""
     end
   end
 
-  vim.api.nvim_create_autocmd({ "BufWinEnter", "FileType" }, {
+  vim.api.nvim_create_autocmd({ "BufWinEnter", "BufEnter", "WinEnter", "FileType" }, {
     group = tab_augroup,
-    callback = function(args)
+    callback = function()
+      local sess = active_diffs[tabpage]
+      if not sess then
+        return
+      end
       local win = vim.api.nvim_get_current_win()
-      if win == original_win or win == modified_win then
-        ensure_no_winbar()
+      if win == sess.original_win or win == sess.modified_win then
+        sync_window_ui(sess, win)
         -- Re-apply critical window options that might get reset by ftplugins/autocmds
         vim.wo[win].wrap = false
+        welcome_window.sync(win)
       end
     end,
   })

lua/codediff/ui/view/inline_view.lua

@@ -9,6 +9,7 @@ local diff_module = require("codediff.core.diff")
 local inline = require("codediff.ui.inline")
 local semantic = require("codediff.ui.semantic_tokens")
 local layout = require("codediff.ui.layout")
+local welcome_window = require("codediff.ui.view.welcome_window")
 
 local helpers = require("codediff.ui.view.helpers")
 local panel = require("codediff.ui.view.panel")
@@ -105,6 +106,7 @@ function M.create(session_config, filetype, on_ready)
     vim.bo[mod_scratch].buftype = "nofile"
     pcall(vim.api.nvim_buf_set_name, mod_scratch, "CodeDiff " .. tabpage .. ".inline")
     vim.api.nvim_win_set_buf(modified_win, mod_scratch)
+    welcome_window.sync(modified_win)
 
     local orig_scratch = vim.api.nvim_create_buf(false, true)
     vim.bo[orig_scratch].buftype = "nofile"
@@ -171,6 +173,7 @@ function M.create(session_config, filetype, on_ready)
   else
     vim.api.nvim_win_set_buf(modified_win, modified_info.bufnr)
   end
+  welcome_window.sync(modified_win)
 
   -- Load original buffer (hidden — never displayed in a window)
   if original_is_virtual and original_info.needs_edit then
@@ -378,6 +381,7 @@ function M.update(tabpage, session_config, auto_scroll_to_first_hunk)
     end
     vim.api.nvim_win_set_buf(modified_win, mod_buf)
   end
+  welcome_window.sync(modified_win)
 
   local should_auto_scroll = auto_scroll_to_first_hunk == true
 
@@ -551,6 +555,7 @@ function M.show_single_file(tabpage, file_path, opts)
     file_bufnr = vim.api.nvim_create_buf(false, true)
     vim.bo[file_bufnr].buftype = "nofile"
     vim.api.nvim_win_set_buf(mod_win, file_bufnr)
+    welcome_window.sync(mod_win)
     local ft = vim.filetype.match({ filename = opts.rel_path or file_path })
     if ft then
       vim.bo[file_bufnr].filetype = ft
@@ -575,6 +580,7 @@ function M.show_single_file(tabpage, file_path, opts)
     file_bufnr = vim.fn.bufadd(file_path)
     vim.fn.bufload(file_bufnr)
     vim.api.nvim_win_set_buf(mod_win, file_bufnr)
+    welcome_window.sync(mod_win)
   end
 
   -- Update session state
@@ -588,6 +594,42 @@ function M.show_single_file(tabpage, file_path, opts)
 
   local view_keymaps = require("codediff.ui.view.keymaps")
   view_keymaps.setup_all_keymaps(tabpage, empty_buf, file_bufnr, true)
+  welcome_window.sync_later(mod_win)
+end
+
+--- Show the welcome page in the inline diff window
+---@param tabpage number
+---@param load_bufnr number Welcome buffer created by welcome.create_buffer
+function M.show_welcome(tabpage, load_bufnr)
+  local session = lifecycle.get_session(tabpage)
+  if not session then
+    return
+  end
+
+  local mod_win = session.modified_win
+  if not mod_win or not vim.api.nvim_win_is_valid(mod_win) then
+    return
+  end
+
+  if session.modified_bufnr and vim.api.nvim_buf_is_valid(session.modified_bufnr) then
+    inline.clear(session.modified_bufnr)
+    auto_refresh.disable(session.modified_bufnr)
+  end
+
+  vim.api.nvim_win_set_buf(mod_win, load_bufnr)
+  welcome_window.sync(mod_win)
+
+  local empty_buf = vim.api.nvim_create_buf(false, true)
+  vim.bo[empty_buf].buftype = "nofile"
+
+  lifecycle.update_buffers(tabpage, empty_buf, load_bufnr)
+  lifecycle.update_paths(tabpage, "", "")
+  lifecycle.update_revisions(tabpage, nil, nil)
+  lifecycle.update_diff_result(tabpage, {})
+
+  local view_keymaps = require("codediff.ui.view.keymaps")
+  view_keymaps.setup_all_keymaps(tabpage, empty_buf, load_bufnr, true)
+  welcome_window.sync_later(mod_win)
 end
 
 return M

lua/codediff/ui/view/keymaps.lua

@@ -683,9 +683,13 @@ function M.setup_all_keymaps(tabpage, original_bufnr, modified_bufnr, is_explore
 
   -- Help keymap (g?) - show floating window with available keymaps
   if keymaps.show_help then
-    local help = require("codediff.ui.keymap_help")
     lifecycle.set_tab_keymap(tabpage, "n", keymaps.show_help, function()
-      help.toggle(tabpage)
+      local ok, help = pcall(require, "codediff.ui.keymap_help")
+      if ok and help then
+        help.toggle(tabpage)
+      else
+        vim.notify_once("[codediff] failed to load codediff.ui.keymap_help: " .. tostring(help), vim.log.levels.WARN)
+      end
     end, { desc = "Show keymap help" })
   end
 

lua/codediff/ui/view/side_by_side.lua

@@ -18,6 +18,7 @@ local render = require("codediff.ui.view.render")
 local view_keymaps = require("codediff.ui.view.keymaps")
 local conflict_window = require("codediff.ui.view.conflict_window")
 local panel = require("codediff.ui.view.panel")
+local welcome_window = require("codediff.ui.view.welcome_window")
 
 local is_virtual_revision = helpers.is_virtual_revision
 local prepare_buffer = helpers.prepare_buffer
@@ -72,6 +73,8 @@ function M.create(session_config, filetype, on_ready)
     pcall(vim.api.nvim_buf_set_name, mod_scratch, "CodeDiff " .. tabpage .. ".2")
     vim.api.nvim_win_set_buf(original_win, orig_scratch)
     vim.api.nvim_win_set_buf(modified_win, mod_scratch)
+    welcome_window.sync(original_win)
+    welcome_window.sync(modified_win)
 
     -- Create placeholder buffer info (will be updated by explorer)
     original_info = { bufnr = orig_scratch }
@@ -107,6 +110,8 @@ function M.create(session_config, filetype, on_ready)
     else
       vim.api.nvim_win_set_buf(modified_win, modified_info.bufnr)
     end
+    welcome_window.sync(original_win)
+    welcome_window.sync(modified_win)
   end
 
   -- Clean up initial buffer
@@ -662,6 +667,9 @@ function M.update(tabpage, session_config, auto_scroll_to_first_hunk)
     end
   end
 
+  welcome_window.sync(original_win)
+  welcome_window.sync(modified_win)
+
   -- Update lifecycle session metadata
   lifecycle.update_paths(tabpage, session_config.original_path, session_config.modified_path)
 
@@ -729,6 +737,7 @@ local function show_single_file(tabpage, opts)
   -- Load the file into the kept window
   if keep_win and vim.api.nvim_win_is_valid(keep_win) then
     vim.api.nvim_win_set_buf(keep_win, opts.load_bufnr)
+    welcome_window.sync(keep_win)
 
     -- Create a scratch buffer as placeholder for the empty side
     local empty_buf = vim.api.nvim_create_buf(false, true)
@@ -747,6 +756,9 @@ local function show_single_file(tabpage, opts)
   end
 
   layout.arrange(tabpage)
+  if keep_win and vim.api.nvim_win_is_valid(keep_win) then
+    welcome_window.sync_later(keep_win)
+  end
 end
 
 -- Load a real file from disk, return bufnr
@@ -805,4 +817,12 @@ function M.show_deleted_virtual_file(tabpage, git_root, file_path, revision)
   })
 end
 
+--- Show the welcome page in a single pane (modified side)
+function M.show_welcome(tabpage, load_bufnr)
+  show_single_file(tabpage, {
+    keep = "modified",
+    load_bufnr = load_bufnr,
+  })
+end
+
 return M