chore: Update docs for - fix: Segfault on dropping picker mid-rescan

Author: dmtrKovalenko

crates/fff-core/src/file_picker.rs

@@ -137,6 +137,8 @@ pub(crate) struct FileSync {
     files: StableVec<FileItem>,
     indexable_count: usize,
     base_count: usize,
+    /// Number of active present files that exists in the file sytsem
+    live_count: usize,
     /// Sorted directory table. `StableVec` so post-scan snapshots can keep
     /// the allocation alive across a picker drop without copying, and so
     /// concurrent readers observe a consistent view via the same shared
@@ -159,6 +161,7 @@ impl FileSync {
             files: StableVec::from_vec_with_reserve(Vec::new(), MAX_OVERFLOW_FILES),
             indexable_count: 0,
             base_count: 0,
+            live_count: 0,
             dirs: StableVec::from_vec_with_reserve(Vec::new(), 0),
             overflow_builder: None,
             git_workdir: None,
@@ -321,10 +324,11 @@ impl FileSync {
                 overflow_arena
             };
             if predicate(file, arena) {
-                file.delete();
+                file.set_deleted(true);
                 tombstoned += 1;
             }
         }
+        self.live_count -= tombstoned;
         tombstoned
     }
 }
@@ -566,6 +570,12 @@ impl FilePicker {
         self.sync_data.files()
     }
 
+    /// Count of live (non-tombstoned) files. O(1).
+    #[inline]
+    pub fn live_file_count(&self) -> usize {
+        self.sync_data.live_count
+    }
+
     pub fn get_overflow_files(&self) -> &[FileItem] {
         self.sync_data.overflow_files()
     }
@@ -871,7 +881,7 @@ impl FilePicker {
             "Fuzzy search",
         );
 
-        let total_files = files.len();
+        let total_files = self.live_file_count();
         let location = query.location;
 
         // Get effective query for max_typos calculation (without location suffix)
@@ -1060,7 +1070,7 @@ impl FilePicker {
                     items: vec![],
                     scores: vec![],
                     total_matched,
-                    total_files: self.sync_data.files().len(),
+                    total_files: self.live_file_count(),
                     total_dirs,
                     location,
                 };
@@ -1074,7 +1084,7 @@ impl FilePicker {
                 items,
                 scores,
                 total_matched,
-                total_files: self.sync_data.files().len(),
+                total_files: self.live_file_count(),
                 total_dirs,
                 location,
             };
@@ -1422,7 +1432,7 @@ impl FilePicker {
                     "File market for modification doesn't exists or not accessible"
                 )
             })
-            .ok()?; // if we can't read metadata this file either doesn't exists or not accessible
+            .ok()?;
 
         let size = metadata.len();
         let modified_time = metadata
@@ -1431,7 +1441,8 @@ impl FilePicker {
             .and_then(|t| t.duration_since(SystemTime::UNIX_EPOCH).ok())
             .map(|d| d.as_secs());
 
-        if file.is_deleted() {
+        let was_deleted = file.is_deleted();
+        if was_deleted {
             file.set_deleted(false);
         }
 
@@ -1451,7 +1462,13 @@ impl FilePicker {
             }
         }
 
-        Some(&*self.sync_data.get_file_mut(pos)?)
+        // Increment after dropping the mutable file reference so the
+        // reborrow for the return doesn't conflict.
+        if was_deleted {
+            self.sync_data.live_count += 1;
+        }
+
+        self.sync_data.files().get(pos)
     }
 
     /// Adds a new file to picker, if the file can not be added returns `None`
@@ -1495,6 +1512,7 @@ impl FilePicker {
             return None;
         }
 
+        self.sync_data.live_count += 1;
         self.sync_data.files.last()
     }
 
@@ -1505,19 +1523,12 @@ impl FilePicker {
             Ok(index) => {
                 let file = &mut self.sync_data.files[index];
                 file.set_deleted(true);
-                // Clear any cached git status — the tombstone no longer
-                // corresponds to a real worktree file, so any previously
-                // cached status (e.g. `WT_MODIFIED` from before the delete)
-                // is actively misleading. All user-facing search
-                // paths filter `is_deleted()` so this is invisible today,
-                // but keeping the invariant "tombstone ⇒ git_status=None"
-                // means a new reader that forgets the filter can't leak
-                // stale data.
                 file.git_status = None;
                 file.invalidate_mmap(&self.cache_budget);
                 if let Some(ref overlay) = self.sync_data.bigram_overlay {
                     overlay.write().delete_file(index);
                 }
+                self.sync_data.live_count -= 1;
                 true
             }
             Err(_) => {
@@ -1528,6 +1539,7 @@ impl FilePicker {
                     file.set_deleted(true);
                     file.git_status = None;
                     file.invalidate_mmap(&self.cache_budget);
+                    self.sync_data.live_count -= 1;
                     true
                 } else {
                     false
@@ -1979,6 +1991,7 @@ impl FileSync {
             files: StableVec::from_vec_with_reserve(files, MAX_OVERFLOW_FILES),
             indexable_count,
             base_count,
+            live_count: base_count,
             dirs: StableVec::from_vec_with_reserve(dirs, 0),
             overflow_builder: None,
             git_workdir,

crates/fff-core/src/grep.rs

@@ -11,7 +11,7 @@ use crate::{
     constraints::apply_constraints,
     extract_bigrams,
     sort_buffer::sort_with_buffer,
-    types::{ContentCacheBudget, FileItem},
+    types::{ContentCacheBudget, FileItem, FileSliceExt},
 };
 use aho_corasick::AhoCorasick;
 pub use fff_grep::{
@@ -960,7 +960,7 @@ pub(crate) fn multi_grep_search<'a>(
     arena: crate::simd_path::ArenaPtr,
     overflow_arena: crate::simd_path::ArenaPtr,
 ) -> GrepResult<'a> {
-    let total_files = files.len();
+    let total_files = files.live_count();
 
     if patterns.is_empty() || patterns.iter().all(|p| p.is_empty()) {
         return GrepResult {
@@ -1859,7 +1859,7 @@ pub(crate) fn grep_search<'a>(
     arena: crate::simd_path::ArenaPtr,
     overflow_arena: crate::simd_path::ArenaPtr,
 ) -> GrepResult<'a> {
-    let total_files = files.len();
+    let total_files = files.live_count();
 
     // Extract the grep text and file constraints from the parsed query.
     // For grep, the search pattern is the original query with constraint tokens

crates/fff-core/src/stable_vec.rs

@@ -99,8 +99,10 @@ impl<T> StableVec<T> {
         true
     }
 
+    // this method is specifically private becuase you probably need to use
+    // live_count if you are trying to access this method
     #[inline]
-    pub fn len(&self) -> usize {
+    fn len(&self) -> usize {
         self.inner.len.load(Ordering::Acquire)
     }
 

crates/fff-core/src/types.rs

@@ -38,6 +38,17 @@ impl FFFStringStorage for ArenaPtr {
     }
 }
 
+pub trait FileSliceExt {
+    fn live_count(&self) -> usize;
+}
+
+impl FileSliceExt for [FileItem] {
+    #[inline]
+    fn live_count(&self) -> usize {
+        self.iter().filter(|f| !f.is_deleted()).count()
+    }
+}
+
 /// Cached file contents — mmap on Unix, heap buffer on Windows.
 ///
 /// On Windows, memory-mapped files hold the file handle open and prevent

crates/fff-core/tests/drop_during_post_scan.rs

@@ -122,11 +122,7 @@ fn drop_picker_concurrent_with_search_no_segfault() {
             if let Ok(guard) = sp_clone.read() {
                 if let Some(picker) = guard.as_ref() {
                     let query = parser.parse("func");
-                    let _ = picker.fuzzy_search(
-                        &query,
-                        None,
-                        FuzzySearchOptions::default(),
-                    );
+                    let _ = picker.fuzzy_search(&query, None, FuzzySearchOptions::default());
                 }
             }
             std::thread::sleep(Duration::from_millis(1));

doc/fff.nvim.txt

@@ -1,5 +1,5 @@
 *fff.nvim.txt*
-                              For Neovim >= 0.10.0    Last change: 2026 May 08
+                              For Neovim >= 0.10.0    Last change: 2026 May 11
 
 ==============================================================================
 Table of Contents                                 *fff.nvim-table-of-contents*