fix(grep): align preview highlight stripping with Rust query parser

crates/fff-nvim/src/lib.rs

@@ -5,8 +5,9 @@ use fff::frecency::FrecencyTracker;
 use fff::path_utils::expand_tilde;
 use fff::query_tracker::QueryTracker;
 use fff::{
-    DbHealthChecker, Error, FFFMode, FileSearchConfig, FuzzySearchOptions, PaginationArgs,
-    QueryParser, Score, SearchResult, SharedFrecency, SharedPicker, SharedQueryTracker,
+    DbHealthChecker, Error, FFFMode, FileSearchConfig, FuzzySearchOptions, GrepConfig,
+    PaginationArgs, QueryParser, Score, SearchResult, SharedFrecency, SharedPicker,
+    SharedQueryTracker,
 };
 use mimalloc::MiMalloc;
 use mlua::prelude::*;
@@ -582,6 +583,18 @@ pub fn get_historical_grep_query(_: &Lua, offset: usize) -> LuaResult<Option<Str
         .into_lua_result()
 }
 
+/// Parse a grep query string and return its text portion (with constraints stripped).
+///
+/// Uses the Rust `GrepConfig` parser as the single source of truth, so Lua
+/// code never needs to re-implement constraint detection.
+pub fn parse_grep_query(lua: &Lua, query: String) -> LuaResult<LuaTable> {
+    let parser = QueryParser::new(GrepConfig);
+    let parsed = parser.parse(&query);
+    let table = lua.create_table()?;
+    table.set("grep_text", parsed.grep_text())?;
+    Ok(table)
+}
+
 pub fn wait_for_initial_scan(_: &Lua, timeout_ms: Option<u64>) -> LuaResult<bool> {
     // Extract the scan signal Arc WITHOUT holding the read lock, so the
     // scan thread can acquire the write lock to store its results.
@@ -822,6 +835,7 @@ fn create_exports(lua: &Lua) -> LuaResult<LuaTable> {
     exports.set("health_check", lua.create_function(health_check)?)?;
     exports.set("shorten_path", lua.create_function(shorten_path)?)?;
     exports.set("hex_dump", lua.create_function(hex_dump::hex_dump)?)?;
+    exports.set("parse_grep_query", lua.create_function(parse_grep_query)?)?;
 
     Ok(exports)
 }

lua/fff/fuzzy.lua

@@ -46,6 +46,7 @@ M.get_git_root = rust_module.get_git_root
 
 -- Grep functions
 M.live_grep = rust_module.live_grep
+M.parse_grep_query = rust_module.parse_grep_query
 
 -- Utility functions
 M.health_check = rust_module.health_check

lua/fff/location_utils.lua

@@ -178,16 +178,13 @@ function M.highlight_grep_matches(bufnr, location, namespace)
 
   local query = location.grep_query
 
-  -- Extract the actual search text from the grep query (strip file constraints like *.rs /src/)
-  -- The query parser uses space-separated tokens; the first non-constraint token is the pattern.
-  -- Simple heuristic: strip tokens that look like constraints (start with *, /, or !)
-  local search_text = query
-  local parts = vim.split(query, '%s+')
-  local text_parts = {}
-  for _, part in ipairs(parts) do
-    if part ~= '' and not part:match('^[%*!/]') and not part:match('^%.') then table.insert(text_parts, part) end
-  end
-  if #text_parts > 0 then search_text = text_parts[1] end
+  -- Use the Rust GrepConfig parser as the single source of truth for
+  -- stripping constraint tokens. This avoids duplicating constraint
+  -- detection in Lua, which would break whenever a new token type is added.
+  local fuzzy = require('fff.fuzzy')
+  local parsed = fuzzy.parse_grep_query(query)
+  local search_text = parsed.grep_text
+  if search_text == '' then search_text = query end
 
   if not search_text or search_text == '' then return nil end