1.3.0: serialize GanttController fetches and add GanttActivityAction style

CHANGELOG.md

@@ -1,3 +1,12 @@
+## [1.3.0] - 2026-09-22
+
+@a-nisi-insideapp
+
+- Fix a race between overlapping `fetch()` calls (e.g. the automatic fetch on mount racing a caller's own refetch triggered by async filter restoration): `GanttController` now serializes fetches instead of running them concurrently — at most one fetch is ever in flight, and any `fetch()` call that arrives while one is running is coalesced into a single follow-up run instead of starting a second one. This removes the need for callers to guard against stale responses overwriting fresher ones.
+- A fetch listener that throws (a failing `activitiesAsync`/`holidaysAsync`, for instance) no longer leaves `GanttController` permanently unable to fetch, and no longer skips the remaining listeners. The failure is reported through `FlutterError.reportError` instead of being swallowed.
+- Fix a `ConcurrentModificationError` when a fetch listener was added or removed while a fetch was in flight — for example a `Gantt` widget disposed while its data was still loading.
+- Add an optional `style` to `GanttActivityAction`, applied to the action's `IconButton`, so callers can customize the button (e.g. its color on hover).
+
 ## [1.2.2] - 2026-04-28
 
 @rickypid

example/pubspec.lock

@@ -36,7 +36,7 @@ packages:
       path: ".."
       relative: true
     source: path
-    version: "1.2.2"
+    version: "1.3.0"
   flutter_lints:
     dependency: "direct dev"
     description:
@@ -86,10 +86,10 @@ packages:
     dependency: transitive
     description:
       name: meta
-      sha256: "23f08335362185a5ea2ad3a4e597f1375e78bce8a040df5c600c8d3552ef2394"
+      sha256: "1741988757a65eb6b36abe716829688cf01910bbf91c34354ff7ec1c3de2b349"
       url: "https://pub.dev"
     source: hosted
-    version: "1.17.0"
+    version: "1.18.0"
   nested:
     dependency: transitive
     description:
@@ -128,5 +128,5 @@ packages:
     source: hosted
     version: "2.2.0"
 sdks:
-  dart: ">=3.9.0-0 <4.0.0"
+  dart: ">=3.10.0-0 <4.0.0"
   flutter: ">=1.17.0"

lib/src/classes/activity.dart

@@ -13,11 +13,15 @@ class GanttActivityAction {
   /// Optional tooltip text for the action.
   final String? tooltip;
 
+  /// Optional style for the action button.
+  final ButtonStyle? style;
+
   /// Creates an activity action with an icon, tap handler, and optional tooltip.
   const GanttActivityAction({
     required this.icon,
     required this.onTap,
     this.tooltip,
+    this.style,
   });
 }
 

lib/src/widgets/activities_list.dart

@@ -84,6 +84,7 @@ class ActivitiesList extends StatelessWidget {
                             padding: EdgeInsets.zero,
                             onPressed: e.onTap,
                             icon: Icon(e.icon, size: theme.cellHeight * 0.8),
+                            style: e.style,
                           );
                           return e.tooltip != null
                               ? Tooltip(message: e.tooltip, child: child)

lib/src/widgets/controller.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart';
 
@@ -164,13 +166,18 @@ class GanttController extends ChangeNotifier {
     notifyListeners();
   }
 
-  final List<VoidCallback> _fetchListener = <VoidCallback>[];
+  bool _fetchInFlight = false;
+  bool _fetchPending = false;
+
+  final List<FutureOr<void> Function()> _fetchListener =
+      <FutureOr<void> Function()>[];
 
   /// Adds a listener to be called when data needs to be fetched.
-  void addFetchListener(VoidCallback fn) => _fetchListener.add(fn);
+  void addFetchListener(FutureOr<void> Function() fn) => _fetchListener.add(fn);
 
   /// Removes a fetch listener.
-  void removeFetchListener(VoidCallback fn) => _fetchListener.remove(fn);
+  void removeFetchListener(FutureOr<void> Function() fn) =>
+      _fetchListener.remove(fn);
 
   /// Removes all fetch listeners.
   void removeAllFetchListener() {
@@ -180,9 +187,56 @@ class GanttController extends ChangeNotifier {
   }
 
   /// Notifies all fetch listeners to load new data.
+  ///
+  /// If a fetch is already in flight, this does not start a second one in
+  /// parallel — it just marks that another fetch is needed and returns.
+  /// Once the running fetch completes, it immediately re-runs exactly once
+  /// more, picking up whatever changed in the meantime. This guarantees at
+  /// most one fetch in flight at any time, so a slower/older fetch can never
+  /// overwrite a faster/newer one — there is nothing left to race against.
+  ///
+  /// A listener that throws is reported through [FlutterError.reportError]: it
+  /// neither skips the remaining listeners nor leaves the controller unable to
+  /// fetch again.
   void fetch() {
-    for (var fn in _fetchListener) {
-      fn();
+    if (_fetchInFlight) {
+      _fetchPending = true;
+      return;
+    }
+    unawaited(_runFetch());
+  }
+
+  Future<void> _runFetch() async {
+    _fetchInFlight = true;
+    try {
+      // Iterate over a snapshot: listeners may be added or removed while this
+      // loop is suspended on an await (a Gantt widget being disposed mid-fetch
+      // removes its own listener), which would otherwise throw a
+      // ConcurrentModificationError.
+      for (final fn in List<FutureOr<void> Function()>.of(_fetchListener)) {
+        try {
+          await Future.sync(fn);
+        } catch (error, stackTrace) {
+          // A listener that throws must not abort the remaining listeners nor
+          // leave the controller wedged, but the failure still has to surface.
+          FlutterError.reportError(
+            FlutterErrorDetails(
+              exception: error,
+              stack: stackTrace,
+              library: 'flutter_gantt',
+              context: ErrorDescription(
+                'while running a GanttController fetch listener',
+              ),
+            ),
+          );
+        }
+      }
+    } finally {
+      _fetchInFlight = false;
+    }
+    if (_fetchPending) {
+      _fetchPending = false;
+      unawaited(_runFetch());
     }
   }
 

pubspec.yaml

@@ -1,6 +1,6 @@
 name: flutter_gantt
 description: "Flutter package for rendering an interactive and customizable Gantt chart widget."
-version: 1.2.2
+version: 1.3.0
 homepage: https://github.com/insideapp-srl/flutter_gantt
 repository: https://github.com/insideapp-srl/flutter_gantt