fix: missing filename header when scrolling up in live_grep (#470)

lua/fff/picker_ui/file_renderer.lua

@@ -18,8 +18,9 @@ local M = {}
 --- Render a file item line
 --- @param item FileItem File item from Rust
 --- @param ctx ListRenderContext Render context with all state
+--- @param item_idx number|nil 1-based item index in ctx.items
 --- @return string[] Array of line strings (always exactly 1)
-function M.render_line(item, ctx)
+function M.render_line(item, ctx, item_idx) -- luacheck: ignore item_idx
   local icons = require('fff.file_picker.icons')
   local lines = {}
 

lua/fff/picker_ui/grep_renderer.lua

@@ -254,10 +254,14 @@ end
 --- or 1 line [match] for subsequent matches in the same file.
 ---@param item FileItem Grep match item
 ---@param ctx table Render context
+---@param item_idx number 1-based item index in ctx.items
 ---@return string[]
-function M.render_line(item, ctx)
-  local is_new_group = (item.relative_path ~= ctx._grep_last_file)
-  ctx._grep_last_file = item.relative_path
+function M.render_line(item, ctx, item_idx)
+  -- First rendered item in this pass always gets header — fixes missing header
+  -- when paginating backward in multi-page grep results (ctx is fresh per render).
+  local is_first_visible = (item_idx == ctx.iter_start)
+  local is_new_group = is_first_visible or (item.relative_path ~= ctx.grep_last_file)
+  ctx.grep_last_file = item.relative_path
 
   local match_line = render_match_line(item, ctx)
 

lua/fff/picker_ui/list_renderer.lua

@@ -98,7 +98,7 @@ local function generate_item_lines(ctx)
     local item = ctx.items[i]
     local item_start_line = #lines + 1
 
-    local item_lines = renderer.render_line(item, ctx)
+    local item_lines = renderer.render_line(item, ctx, i)
     vim.list_extend(lines, item_lines)
 
     local item_end_line = #lines