fix: Do not start fallback grep if index is not ready

README.md

@@ -438,6 +438,10 @@ require('fff').setup({
     enable_filename_constraint = false, -- treat filename-like tokens (e.g. `score.rs`) in a grep query as a file-path filter scoping the search; off = searched as literal text
     location_format = ':%d:%d', -- printf format for line:col prefix in grep results, e.g. ':%d' for line-only
   },
+  suggestions = {
+    enabled = true, -- when a query has no results, look them up in the other mode (files <-> grep) and show as a hint
+    grep_time_budget_ms = 50, -- hard cap for the grep hint in file mode; it is skipped until content indexing finishes
+  },
   debug = {
     enabled = false, -- show the file info panel next to the preview
     show_scores = false, -- inline scores in the file list

crates/fff-nvim/src/lib.rs

@@ -612,6 +612,11 @@ pub fn get_scan_progress(lua: &Lua, _: ()) -> LuaResult<LuaValue> {
     let table = lua.create_table()?;
     table.set("scanned_files_count", progress.scanned_files_count)?;
     table.set("is_scanning", progress.is_scanning)?;
+    table.set("is_warmup_complete", progress.is_warmup_complete)?;
+    let is_index_ready =
+        picker.has_content_indexing() && picker.bigram_index().is_some() && !progress.is_scanning;
+
+    table.set("is_index_ready", is_index_ready)?;
     Ok(LuaValue::Table(table))
 }
 

lua/fff/conf.lua

@@ -68,6 +68,10 @@ local M = {}
 --- @field trim_whitespace boolean
 --- @field location_format string
 
+--- @class FffSuggestionsConfig
+--- @field enabled boolean
+--- @field grep_time_budget_ms number
+
 --- @alias FffSelectAction 'edit' | 'split' | 'vsplit' | 'tab'
 
 --- @class FffSelectConfig
@@ -98,6 +102,7 @@ local M = {}
 --- @field wrap_around boolean
 --- @field file_picker table
 --- @field grep FffGrepConfig
+--- @field suggestions FffSuggestionsConfig
 
 ---@class fff.conf.State
 local state = {
@@ -458,6 +463,11 @@ local function init()
       current_file_label = '(current)',
       fuzzy_query_highlighting = false,
     },
+    -- Cross-mode suggestions shown when a query has no results
+    suggestions = {
+      enabled = true,
+      grep_time_budget_ms = 50, -- Hard cap for the grep hint in file mode (it never runs before content indexing finishes)
+    },
     -- grep settings
     grep = {
       max_file_size = 10 * 1024 * 1024, -- Skip files larger than 10MB

lua/fff/file_picker/init.lua

@@ -150,14 +150,22 @@ end
 function M.is_initialized() return M.state.initialized end
 
 --- Get scan progress information
---- @return table Progress information with scanned_files_count, is_scanning
+--- @return table Progress information with scanned_files_count, is_scanning, is_warmup_complete, is_index_ready
 function M.get_scan_progress()
-  if not M.state.initialized then return { total_files = 0, scanned_files_count = 0, is_scanning = false } end
+  if not M.state.initialized then
+    return {
+      total_files = 0,
+      scanned_files_count = 0,
+      is_scanning = false,
+      is_warmup_complete = false,
+      is_index_ready = false,
+    }
+  end
 
   local ok, result = pcall(fuzzy.get_scan_progress)
   if not ok then
     vim.notify('Failed to get scan progress: ' .. tostring(result), vim.log.levels.WARN)
-    return { scanned_files_count = 0, is_scanning = false }
+    return { scanned_files_count = 0, is_scanning = false, is_warmup_complete = false, is_index_ready = false }
   end
 
   return result

lua/fff/picker_ui/search_manager.lua

@@ -81,7 +81,8 @@ function M.update_results_sync()
 
   S.suggestion_items = nil
   S.suggestion_source = nil
-  if #results == 0 and S.query ~= '' then
+  local suggestions_enabled = (S.config.suggestions or {}).enabled ~= false
+  if #results == 0 and S.query ~= '' and suggestions_enabled then
     if S.mode == 'grep' then
       local suggestion_results =
         file_picker.search_files_paginated(S.query, S.current_file_cache, S.config.max_threads, nil, 0, page_size)
@@ -90,8 +91,7 @@ function M.update_results_sync()
         S.suggestion_source = 'files'
       end
     else
-      local grep_result = grep.search(S.query, 0, page_size, S.grep_config, 'plain')
-      local grep_items = grep_result and grep_result.items or {}
+      local grep_items = M.suggestion_grep(page_size)
       if #grep_items > 0 then
         S.suggestion_items = grep_items
         S.suggestion_source = 'grep'
@@ -113,6 +113,23 @@ function M.update_results_sync()
   P.render_debounced()
 end
 
+-- Hint only: hard time budget (a zero-hit query would otherwise scan every file)
+-- and skipped unless the bigram index is built, since without it grep is a cold disk scan.
+---@param page_size number
+---@return table[]
+function M.suggestion_grep(page_size)
+  if not file_picker.get_scan_progress().is_index_ready then return {} end
+  local suggest_config = S.config.suggestions or {}
+
+  local grep_config = vim.tbl_extend('force', S.grep_config or S.config.grep or {}, {
+    enforce_time_budget = true,
+    time_budget_ms = suggest_config.grep_time_budget_ms or 50,
+  })
+  local ok, grep_result = pcall(grep.search, S.query, 0, page_size, grep_config, 'plain')
+  if not ok or not grep_result then return {} end
+  return grep_result.items or {}
+end
+
 function M.load_page_at_index(new_page_index, adjust_cursor_fn)
   local ok, err, results
   local page_size = S.pagination.page_size