perf(git): stash sidebar window in state

lua/git/status_win.lua

@@ -32,6 +32,7 @@ local SIDEBAR_WIDTH = 50
 ---@field gitdir string
 ---@field worktree string
 ---@field lines table<integer, ow.Git.StatusEntry>
+---@field sidebar_win integer?
 ---@field diff_left_win integer?
 ---@field diff_right_win integer?
 ---@field user_aucmd integer?
@@ -44,6 +45,8 @@ local group =
     vim.api.nvim_create_augroup("ow.git.status_win", { clear = false })
 local ns = vim.api.nvim_create_namespace("ow.git.status_win")
 
+---Find the sidebar window in the current tabpage by filetype. Used as a
+---fallback when we don't have a `StatusState` handy (e.g. M.toggle).
 ---@return integer? win
 ---@return integer? bufnr
 local function find_sidebar()
@@ -55,6 +58,20 @@ local function find_sidebar()
     end
 end
 
+---Return the sidebar window stashed on `s`, validating that it's still
+---live. Falls back to `find_sidebar` if the stashed handle is gone.
+---@param s ow.Git.StatusState
+---@return integer?
+local function sidebar_win_for(s)
+    local win = s.sidebar_win
+    if win and vim.api.nvim_win_is_valid(win) then
+        return win
+    end
+    win = find_sidebar()
+    s.sidebar_win = win
+    return win
+end
+
 ---@param entry ow.Git.StatusEntry
 ---@return string?
 local function entry_code(entry)
@@ -325,15 +342,13 @@ local function refresh(bufnr)
     end
 
     local saved_path, saved_sha
-    for _, win in ipairs(vim.api.nvim_list_wins()) do
-        if vim.api.nvim_win_get_buf(win) == bufnr then
-            local lnum = vim.api.nvim_win_get_cursor(win)[1]
-            local entry = s.lines[lnum]
-            if entry then
-                saved_path = entry.path
-                saved_sha = entry.sha
-            end
-            break
+    local sidebar_win = sidebar_win_for(s)
+    if sidebar_win then
+        local lnum = vim.api.nvim_win_get_cursor(sidebar_win)[1]
+        local entry = s.lines[lnum]
+        if entry then
+            saved_path = entry.path
+            saved_sha = entry.sha
         end
     end
 
@@ -350,10 +365,9 @@ local function refresh(bufnr)
                 (saved_path and entry.path == saved_path)
                 or (saved_sha and entry.sha == saved_sha)
             then
-                for _, win in ipairs(vim.api.nvim_list_wins()) do
-                    if vim.api.nvim_win_get_buf(win) == bufnr then
-                        pcall(vim.api.nvim_win_set_cursor, win, { lnum, 0 })
-                    end
+                local win = sidebar_win_for(s)
+                if win then
+                    pcall(vim.api.nvim_win_set_cursor, win, { lnum, 0 })
                 end
                 break
             end
@@ -554,7 +568,7 @@ local function show_diff(s, entry, focus_left)
         return
     end
     ---@cast entry ow.Git.FileEntry
-    local sidebar_win = find_sidebar()
+    local sidebar_win = sidebar_win_for(s)
     if not sidebar_win then
         return
     end
@@ -788,7 +802,12 @@ local function open(worktree)
     vim.wo[win].winfixwidth = true
     vim.api.nvim_win_set_width(win, SIDEBAR_WIDTH)
 
-    state[bufnr] = { gitdir = gitdir, worktree = worktree, lines = {} }
+    state[bufnr] = {
+        gitdir = gitdir,
+        worktree = worktree,
+        lines = {},
+        sidebar_win = win,
+    }
 
     local function k(lhs, rhs, desc)
         vim.keymap.set(