Prevent stale file search results from being labeled with a new query (#49946)

## Why

The asynchronous matcher can return results for the previous query while a new query is still running. Labeling those results with the latest query produces a mismatched search snapshot.

## What changed

Only report a file search snapshot when its pattern atoms match the currently requested pattern. Extract snapshot conversion into `snapshot::for_query`, which skips pending results from an older pattern.

## Testing

Add a regression test that changes the query from empty to `bet`, verifies that the old snapshot is withheld, and checks that the completed snapshot contains `beta.txt` with the expected match indices and counts.

GitOrigin-RevId: 01b62b822db69e15480d3233b66ec55c45646fad

codex-rs/file-search/src/lib.rs

@@ -35,6 +35,11 @@ use nucleo::pattern::AtomKind;
 use nucleo::pattern::Pattern;
 
 mod cli;
+mod snapshot;
+
+#[cfg(test)]
+#[path = "matcher_tests.rs"]
+mod matcher_tests;
 
 pub use cli::Cli;
 
@@ -553,45 +558,15 @@ fn matcher_worker(
             recv(next_notify) -> _ => {
                 will_notify = false;
                 let status = nucleo.tick(TICK_TIMEOUT_MS);
-                if status.changed {
-                    let snapshot = nucleo.snapshot();
-                    let limit = inner.limit.min(snapshot.matched_item_count() as usize);
-                    let pattern = snapshot.pattern().column_pattern(0);
-                    let matches: Vec<_> = snapshot
-                        .matches()
-                        .iter()
-                        .take(limit)
-                        .filter_map(|match_| {
-                            let item = snapshot.get_item(match_.idx)?;
-                            let full_path = item.data.full_path.as_ref();
-                            let (root_idx, relative_path) = get_file_path(Path::new(full_path), &inner.search_directories)?;
-                            let indices = if let Some(indices_matcher) = indices_matcher.as_mut() {
-                                let mut idx_vec = Vec::<u32>::new();
-                                let haystack = item.matcher_columns[0].slice(..);
-                                let _ = pattern.indices(haystack, indices_matcher, &mut idx_vec);
-                                idx_vec.sort_unstable();
-                                idx_vec.dedup();
-                                Some(idx_vec)
-                            } else {
-                                None
-                            };
-                            Some(FileMatch {
-                                score: match_.score,
-                                path: PathBuf::from(relative_path),
-                                match_type: item.data.match_type,
-                                root: inner.search_directories[root_idx].clone(),
-                                indices,
-                            })
-                        })
-                        .collect();
-
-                    let snapshot = FileSearchSnapshot {
-                        query: last_query.clone(),
-                        matches,
-                        total_match_count: snapshot.matched_item_count() as usize,
-                        scanned_file_count: snapshot.item_count() as usize,
+                if status.changed
+                    && let Some(snapshot) = snapshot::for_query(
+                        &inner,
+                        &nucleo,
+                        &last_query,
+                        &mut indices_matcher,
                         walk_complete,
-                    };
+                    )
+                {
                     inner.reporter.on_update(&snapshot);
                 }
                 if !status.running && walk_complete {
@@ -710,7 +685,7 @@ mod tests {
     }
 
     #[derive(Default)]
-    struct RecordingReporter {
+    pub(super) struct RecordingReporter {
         updates: Mutex<Vec<FileSearchSnapshot>>,
         complete_times: Mutex<Vec<Instant>>,
         complete_cv: Condvar,

codex-rs/file-search/src/matcher_tests.rs

@@ -0,0 +1,100 @@
+//! Regression coverage for associating asynchronous matcher results with their query.
+
+use super::*;
+use pretty_assertions::assert_eq;
+
+#[test]
+fn query_update_does_not_relabel_pending_matches() {
+    let root = tempfile::tempdir().unwrap();
+    let (work_tx, work_rx) = unbounded();
+    let notify_tx = work_tx.clone();
+    let mut nucleo = Nucleo::new(
+        Config::DEFAULT.match_paths(),
+        Arc::new(move || {
+            let _ = notify_tx.send(WorkSignal::NucleoNotify);
+        }),
+        /*num_threads*/ Some(1),
+        /*columns*/ 1,
+    );
+    let injector = nucleo.injector();
+    for (relative, match_type) in [("", MatchType::Directory), ("beta.txt", MatchType::File)] {
+        let full_path = root.path().join(relative);
+        injector.push(
+            IndexedEntry {
+                full_path: Arc::from(full_path.to_str().unwrap()),
+                match_type,
+            },
+            |_, columns| columns[0] = Utf32String::from(relative),
+        );
+    }
+    while nucleo.tick(/*timeout*/ 10).running {
+        work_rx.recv_timeout(Duration::from_secs(5)).unwrap();
+    }
+    let inner = SessionInner {
+        search_directories: vec![root.path().to_path_buf()],
+        limit: 50,
+        threads: 1,
+        compute_indices: true,
+        respect_gitignore: true,
+        cancelled: Arc::new(AtomicBool::new(false)),
+        shutdown: Arc::new(AtomicBool::new(false)),
+        reporter: Arc::new(tests::RecordingReporter::default()),
+        work_tx,
+    };
+    let mut indices_matcher = Some(Matcher::new(Config::DEFAULT.match_paths()));
+    let initial = snapshot::for_query(
+        &inner,
+        &nucleo,
+        "",
+        &mut indices_matcher,
+        /*walk_complete*/ true,
+    )
+    .unwrap();
+    assert_eq!(initial.matches.len(), 2);
+
+    nucleo.pattern.reparse(
+        /*column*/ 0,
+        "bet",
+        CaseMatching::Ignore,
+        Normalization::Smart,
+        /*append*/ true,
+    );
+    // The requested pattern has changed, but no tick has replaced the previous
+    // snapshot. This is the same intermediate state a busy tick can expose.
+    assert_eq!(
+        snapshot::for_query(
+            &inner,
+            &nucleo,
+            "bet",
+            &mut indices_matcher,
+            /*walk_complete*/ true
+        ),
+        None
+    );
+
+    while nucleo.tick(/*timeout*/ 10).running {
+        work_rx.recv_timeout(Duration::from_secs(5)).unwrap();
+    }
+    assert_eq!(
+        snapshot::for_query(
+            &inner,
+            &nucleo,
+            "bet",
+            &mut indices_matcher,
+            /*walk_complete*/ true
+        ),
+        Some(FileSearchSnapshot {
+            query: "bet".to_string(),
+            matches: vec![FileMatch {
+                score: 84,
+                path: PathBuf::from("beta.txt"),
+                match_type: MatchType::File,
+                root: root.path().to_path_buf(),
+                indices: Some(vec![0, 1, 2]),
+            }],
+            total_match_count: 1,
+            scanned_file_count: 2,
+            walk_complete: true,
+        }),
+    );
+}

codex-rs/file-search/src/snapshot.rs

@@ -0,0 +1,63 @@
+//! Converts matcher snapshots without associating old results with a new query.
+
+use crate::FileMatch;
+use crate::FileSearchSnapshot;
+use crate::IndexedEntry;
+use crate::SessionInner;
+use crate::get_file_path;
+use nucleo::Matcher;
+use nucleo::Nucleo;
+use std::path::Path;
+use std::path::PathBuf;
+
+pub(super) fn for_query(
+    inner: &SessionInner,
+    nucleo: &Nucleo<IndexedEntry>,
+    query: &str,
+    indices_matcher: &mut Option<Matcher>,
+    walk_complete: bool,
+) -> Option<FileSearchSnapshot> {
+    let snapshot = nucleo.snapshot();
+    let pattern = snapshot.pattern().column_pattern(0);
+    // A tick can collect the previous query's results while the new query is
+    // still running. Wait for a matching snapshot before using the new label.
+    if pattern.atoms != nucleo.pattern.column_pattern(0).atoms {
+        return None;
+    }
+    let limit = inner.limit.min(snapshot.matched_item_count() as usize);
+    let matches = snapshot
+        .matches()
+        .iter()
+        .take(limit)
+        .filter_map(|match_| {
+            let item = snapshot.get_item(match_.idx)?;
+            let full_path = item.data.full_path.as_ref();
+            let (root_idx, relative_path) =
+                get_file_path(Path::new(full_path), &inner.search_directories)?;
+            let indices = if let Some(indices_matcher) = indices_matcher.as_mut() {
+                let mut indices = Vec::<u32>::new();
+                let haystack = item.matcher_columns[0].slice(..);
+                let _ = pattern.indices(haystack, indices_matcher, &mut indices);
+                indices.sort_unstable();
+                indices.dedup();
+                Some(indices)
+            } else {
+                None
+            };
+            Some(FileMatch {
+                score: match_.score,
+                path: PathBuf::from(relative_path),
+                match_type: item.data.match_type,
+                root: inner.search_directories[root_idx].clone(),
+                indices,
+            })
+        })
+        .collect();
+    Some(FileSearchSnapshot {
+        query: query.to_string(),
+        matches,
+        total_match_count: snapshot.matched_item_count() as usize,
+        scanned_file_count: snapshot.item_count() as usize,
+        walk_complete,
+    })
+}