feat(watcher): port watchpack safeTime/mtime-accuracy to native watcher

crates/node_binding/napi-binding.d.ts

@@ -473,6 +473,13 @@ export declare class NativeWatcher {
    */
   close(): Promise<void>
   pause(): void
+  /**
+   * Collect the full file/context time tables, mirroring watchpack's
+   * `collectTimeInfoEntries`. Called synchronously from JS after an aggregated
+   * event (or from `getInfo()`) to populate `compiler.fileTimestamps` /
+   * `contextTimestamps`.
+   */
+  getTimeInfo(): NativeTimeInfo
 }
 
 export declare class NativeWatchResult {
@@ -1562,6 +1569,16 @@ export interface JsTap {
   stage: number
 }
 
+/**
+ * watchpack-style time info for a single path, surfaced to webpack as a
+ * `FileSystemInfoEntry`. `timestamp` is absent for directory (context)
+ * entries, whose value is a derived `safe_time` only.
+ */
+export interface JsTimeInfoEntry {
+  safeTime: number
+  timestamp?: number
+}
+
 export interface JsVirtualFile {
   path: string
   content: string
@@ -1782,6 +1799,15 @@ export interface NapiResolveOptions {
   enablePnp?: boolean
 }
 
+/**
+ * The full `fileTimeInfoEntries` / `contextTimeInfoEntries` snapshot, mirroring
+ * watchpack's `collectTimeInfoEntries` output.
+ */
+export interface NativeTimeInfo {
+  fileTimeInfoEntries: Record<string, JsTimeInfoEntry>
+  contextTimeInfoEntries: Record<string, JsTimeInfoEntry>
+}
+
 export interface NativeWatcherOptions {
   followSymlinks?: boolean
   pollInterval?: number

crates/rspack_binding_api/src/native_watcher.rs

@@ -1,5 +1,6 @@
 use std::{
   boxed::Box,
+  collections::HashMap,
   path::{Path, PathBuf},
   time::{Duration, SystemTime, UNIX_EPOCH},
 };
@@ -44,6 +45,23 @@ pub struct NativeWatchResult {
   pub removed_files: Vec<String>,
 }
 
+/// watchpack-style time info for a single path, surfaced to webpack as a
+/// `FileSystemInfoEntry`. `timestamp` is absent for directory (context)
+/// entries, whose value is a derived `safe_time` only.
+#[napi(object)]
+pub struct JsTimeInfoEntry {
+  pub safe_time: f64,
+  pub timestamp: Option<f64>,
+}
+
+/// The full `fileTimeInfoEntries` / `contextTimeInfoEntries` snapshot, mirroring
+/// watchpack's `collectTimeInfoEntries` output.
+#[napi(object)]
+pub struct NativeTimeInfo {
+  pub file_time_info_entries: HashMap<String, JsTimeInfoEntry>,
+  pub context_time_info_entries: HashMap<String, JsTimeInfoEntry>,
+}
+
 #[napi]
 pub struct NativeWatcher {
   watcher: FsWatcher,
@@ -157,6 +175,43 @@ impl NativeWatcher {
 
     Ok(())
   }
+
+  /// Collect the full file/context time tables, mirroring watchpack's
+  /// `collectTimeInfoEntries`. Called synchronously from JS after an aggregated
+  /// event (or from `getInfo()`) to populate `compiler.fileTimestamps` /
+  /// `contextTimestamps`.
+  #[napi]
+  pub fn get_time_info(&self) -> NativeTimeInfo {
+    let (files, contexts) = self.watcher.collect_time_info();
+    let file_time_info_entries = files
+      .into_iter()
+      .map(|(path, entry)| {
+        (
+          path,
+          JsTimeInfoEntry {
+            safe_time: entry.safe_time as f64,
+            timestamp: Some(entry.timestamp as f64),
+          },
+        )
+      })
+      .collect();
+    let context_time_info_entries = contexts
+      .into_iter()
+      .map(|(path, safe_time)| {
+        (
+          path,
+          JsTimeInfoEntry {
+            safe_time: safe_time as f64,
+            timestamp: None,
+          },
+        )
+      })
+      .collect();
+    NativeTimeInfo {
+      file_time_info_entries,
+      context_time_info_entries,
+    }
+  }
 }
 
 fn to_tuple_path_iterator(

crates/rspack_watcher/src/lib.rs

@@ -4,6 +4,7 @@ mod executor;
 mod ignored;
 mod paths;
 mod scanner;
+mod time_info;
 mod trigger;
 
 use std::{sync::Arc, time::SystemTime};
@@ -17,6 +18,7 @@ use rspack_error::Result;
 use rspack_paths::ArcPath;
 use rspack_util::fx_hash::FxHashSet as HashSet;
 use scanner::Scanner;
+pub use time_info::{TimeInfoEntry, TimeInfoTables};
 use tokio::sync::mpsc;
 use trigger::Trigger;
 
@@ -164,6 +166,14 @@ impl FsWatcher {
     }
   }
 
+  /// Collect the full webpack-shaped time tables for all watched files and
+  /// directories. Mirrors watchpack's `collectTimeInfoEntries`; consumed via
+  /// the napi `getTimeInfo()` to populate `fileTimeInfoEntries` /
+  /// `contextTimeInfoEntries`.
+  pub fn collect_time_info(&self) -> TimeInfoTables {
+    self.path_manager.collect_time_info()
+  }
+
   /// Pauses the file system watcher, stopping the execution of the event loop.
   pub fn pause(&self) -> Result<()> {
     self.executor.pause();
@@ -224,7 +234,22 @@ impl FsWatcher {
         .metadata()
         .and_then(|m| m.modified().or_else(|_| m.created()))
       {
-        self.path_manager.set_file_mtime_if_absent(path, mtime);
+        self
+          .path_manager
+          .set_file_mtime_if_absent(path.clone(), mtime);
+        // Seed the watchpack-style time entry for newly-added files so the
+        // first `getTimeInfo()` already carries their conservative safe_time.
+        self.path_manager.set_initial_file_time(path, mtime);
+      }
+    }
+
+    let dirs: Vec<_> = accessor.directories().1.iter().map(|p| p.clone()).collect();
+    for path in dirs {
+      if let Ok(mtime) = path
+        .metadata()
+        .and_then(|m| m.modified().or_else(|_| m.created()))
+      {
+        self.path_manager.set_initial_dir_time(path, mtime);
       }
     }
   }