fix: fix the fixes and add more error logging

src/backend/KQueue.zig

@@ -93,7 +93,7 @@ pub fn deinit(self: *@This(), allocator: std.mem.Allocator) void {
     self.file_watches.deinit(allocator);
     var sit = self.snapshots.iterator();
     while (sit.next()) |entry| {
-        // Keys are borrowed from self.watches and freed in the watches loop above.
+        allocator.free(entry.key_ptr.*); // independently owned; see take_snapshot/scan_dir
         var names = entry.value_ptr.*;
         var nit = names.iterator();
         while (nit.next()) |ne| allocator.free(ne.key_ptr.*);
@@ -436,7 +436,15 @@ fn take_snapshot(self: *@This(), allocator: std.mem.Allocator, dir_path: []const
     self.snapshots_mutex.lock();
     errdefer self.snapshots_mutex.unlock();
     const gop = try self.snapshots.getOrPut(allocator, dir_path);
-    if (!gop.found_existing) gop.value_ptr.* = .empty;
+    if (!gop.found_existing) {
+        // Snapshot outer keys are independently owned so they can be safely
+        // freed in deinit/remove_watch regardless of how the entry was created.
+        gop.key_ptr.* = allocator.dupe(u8, dir_path) catch |e| {
+            _ = self.snapshots.remove(dir_path);
+            return e;
+        };
+        gop.value_ptr.* = .empty;
+    }
     var snapshot = gop.value_ptr;
     for (names.items) |name| {
         if (snapshot.contains(name)) continue;
@@ -464,6 +472,7 @@ pub fn remove_watch(self: *@This(), allocator: std.mem.Allocator, path: []const
     const snap_entry = self.snapshots.fetchRemove(path);
     self.snapshots_mutex.unlock();
     if (snap_entry) |entry| {
+        allocator.free(entry.key); // independently owned; see take_snapshot/scan_dir
         var names = entry.value;
         var it = names.iterator();
         while (it.next()) |ne| {

src/backend/KQueueDir.zig

@@ -78,7 +78,7 @@ pub fn deinit(self: *@This(), allocator: std.mem.Allocator) void {
     self.watches.deinit(allocator);
     var sit = self.snapshots.iterator();
     while (sit.next()) |entry| {
-        // Keys are borrowed from self.watches and freed in the watches loop above.
+        allocator.free(entry.key_ptr.*); // independently owned; see take_snapshot/scan_dir
         var snap = entry.value_ptr.*;
         var nit = snap.iterator();
         while (nit.next()) |ne| allocator.free(ne.key_ptr.*);
@@ -385,7 +385,15 @@ fn take_snapshot(self: *@This(), allocator: std.mem.Allocator, dir_path: []const
     self.snapshots_mutex.lock();
     errdefer self.snapshots_mutex.unlock();
     const gop = try self.snapshots.getOrPut(allocator, dir_path);
-    if (!gop.found_existing) gop.value_ptr.* = .empty;
+    if (!gop.found_existing) {
+        // Snapshot outer keys are independently owned so they can be safely
+        // freed in deinit/remove_watch regardless of how the entry was created.
+        gop.key_ptr.* = allocator.dupe(u8, dir_path) catch |e| {
+            _ = self.snapshots.remove(dir_path);
+            return e;
+        };
+        gop.value_ptr.* = .empty;
+    }
     const snapshot = gop.value_ptr;
     for (entries.items) |e| {
         if (snapshot.contains(e.name)) continue;
@@ -407,6 +415,7 @@ pub fn remove_watch(self: *@This(), allocator: std.mem.Allocator, path: []const
     const snap_entry = self.snapshots.fetchRemove(path);
     self.snapshots_mutex.unlock();
     if (snap_entry) |entry| {
+        allocator.free(entry.key); // independently owned; see take_snapshot/scan_dir
         var snap = entry.value;
         var it = snap.iterator();
         while (it.next()) |ne| allocator.free(ne.key_ptr.*);

src/backend/Windows.zig

@@ -210,7 +210,8 @@ fn thread_fn(
             }
             // Re-arm ReadDirectoryChangesW for the next batch.
             w.overlapped = std.mem.zeroes(windows.OVERLAPPED);
-            _ = win32.ReadDirectoryChangesW(w.handle, w.buf.ptr, buf_size, 1, notify_filter, null, &w.overlapped, null);
+            if (win32.ReadDirectoryChangesW(w.handle, w.buf.ptr, buf_size, 1, notify_filter, null, &w.overlapped, null) == 0)
+                std.log.err("nightwatch: ReadDirectoryChangesW re-arm failed for {s}, future events lost", .{entry.key_ptr.*});
             break;
         }
         watches_mutex.unlock();

src/nightwatch.zig

@@ -225,7 +225,8 @@ pub fn Create(comptime variant: Variant) type {
             fn change_cb(h: *Handler, path: []const u8, event_type: EventType, object_type: ObjectType) error{HandlerFailed}!void {
                 const self: *Interceptor = @fieldParentPtr("handler", h);
                 if (event_type == .created and object_type == .dir and !Backend.watches_recursively) {
-                    self.backend.add_watch(self.allocator, path) catch {};
+                    self.backend.add_watch(self.allocator, path) catch |e|
+                        std.log.err("nightwatch: add_watch failed for {s}: {s}", .{ path, @errorName(e) });
                     recurse_watch(&self.backend, self.allocator, path);
                 }
                 return self.user_handler.change(path, event_type, object_type);
@@ -254,7 +255,8 @@ pub fn Create(comptime variant: Variant) type {
             fn change_cb(h: *PollingHandler, path: []const u8, event_type: EventType, object_type: ObjectType) error{HandlerFailed}!void {
                 const self: *PollingInterceptor = @fieldParentPtr("handler", h);
                 if (event_type == .created and object_type == .dir and !Backend.watches_recursively) {
-                    self.backend.add_watch(self.allocator, path) catch {};
+                    self.backend.add_watch(self.allocator, path) catch |e|
+                        std.log.err("nightwatch: add_watch failed for {s}: {s}", .{ path, @errorName(e) });
                     recurse_watch(&self.backend, self.allocator, path);
                 }
                 return self.user_handler.change(path, event_type, object_type);
@@ -280,7 +282,8 @@ pub fn Create(comptime variant: Variant) type {
                 if (entry.kind != .directory) continue;
                 var buf: [std.fs.max_path_bytes]u8 = undefined;
                 const sub = std.fmt.bufPrint(&buf, "{s}{c}{s}", .{ dir_path, std.fs.path.sep, entry.name }) catch continue;
-                backend.add_watch(allocator, sub) catch {};
+                backend.add_watch(allocator, sub) catch |e|
+                    std.log.err("nightwatch: add_watch failed for {s}: {s}", .{ sub, @errorName(e) });
                 recurse_watch(backend, allocator, sub);
             }
         }