TF-4425 Fix load more not triggered on iOS 18 when fast scrolling to bottom (#4428)

docs/adr/0075-fix-load-more-not-triggered-on-ios-fast-scroll.md

@@ -0,0 +1,43 @@
+# 0075. Fix load more not triggered on iOS when fast scrolling to bottom
+
+Date: 2026-03-31
+
+## Status
+
+- Issues:
+  - [TF-4425 Bug: load more is not working](https://github.com/linagora/tmail-flutter/issues/TF-4425)
+
+## Context
+
+On iOS, `handleLoadMoreEmailsRequest()` was never triggered when users scrolled to the bottom of the email list. The original condition used exact equality:
+
+```dart
+scrollInfo.metrics.pixels == scrollInfo.metrics.maxScrollExtent
+```
+
+**Root cause:** iOS uses `BouncingScrollPhysics` (spring-based simulation), which causes `pixels` to either overshoot or settle slightly short of `maxScrollExtent` depending on scroll speed and device performance. In both cases, `ScrollEndNotification` fires when `pixels != maxScrollExtent`, so the condition is never satisfied.
+
+This behavior is device-dependent — newer/faster devices (iPhone 13 Pro Max, iOS 18) are less affected, while older/slower devices (iPhone 7, iOS 15) exhibit larger deviations. Android is unaffected because `ClampingScrollPhysics` clamps `pixels` exactly within `[0, maxScrollExtent]`.
+
+## Decision
+
+Apply `ClampingScrollPhysics` on iOS only, and replace `==` with `>=`:
+
+```dart
+// physics
+physics: PlatformInfo.isIOS
+    ? const ClampingScrollPhysics()
+    : const AlwaysScrollableScrollPhysics(),
+
+// condition
+scrollInfo.metrics.pixels >= scrollInfo.metrics.maxScrollExtent
+```
+
+`ClampingScrollPhysics` ensures `pixels` is clamped exactly to `maxScrollExtent` at the boundary, making the condition deterministic. The `>=` adds a defensive guard for any residual edge cases.
+
+## Consequences
+
+- Load more works correctly across all iOS versions and device generations.
+- No behavior change on Android or Web.
+- iOS loses the native bounce feel at list boundaries. Acceptable for an email list UI.
+- No risk of duplicate requests due to the existing `isRunning` guard.

lib/features/search/email/presentation/search_email_view.dart

@@ -693,7 +693,7 @@ class SearchEmailView extends GetWidget<SearchEmailController>
         onNotification: (ScrollNotification scrollInfo) {
           if (scrollInfo is ScrollEndNotification
               && controller.searchMoreState != SearchMoreState.waiting
-              && scrollInfo.metrics.pixels == scrollInfo.metrics.maxScrollExtent
+              && scrollInfo.metrics.pixels >= scrollInfo.metrics.maxScrollExtent
               && scrollInfo.metrics.axisDirection == AxisDirection.down) {
             controller.searchMoreEmailsAction();
           }
@@ -701,7 +701,9 @@ class SearchEmailView extends GetWidget<SearchEmailController>
         },
         child: ListView.separated(
           controller: controller.resultSearchScrollController,
-          physics: const AlwaysScrollableScrollPhysics(),
+          physics: PlatformInfo.isIOS
+              ? const ClampingScrollPhysics()
+              : const AlwaysScrollableScrollPhysics(),
           key: const PageStorageKey('list_presentation_email_in_search_view'),
           itemCount: listPresentationEmail.length,
           itemBuilder: (context, index) => _buildEmailItem(

lib/features/thread/presentation/thread_view.dart

@@ -366,7 +366,9 @@ class ThreadView extends GetWidget<ThreadController>
     Widget listView = ListView.separated(
       key: const PageStorageKey('list_presentation_email_in_threads'),
       controller: controller.listEmailController,
-      physics: const AlwaysScrollableScrollPhysics(),
+      physics: PlatformInfo.isIOS
+          ? const ClampingScrollPhysics()
+          : const AlwaysScrollableScrollPhysics(),
       itemCount: listPresentationEmail.length + 2,
       itemBuilder: (context, index) => Obx(() {
         if (index == listPresentationEmail.length) {
@@ -440,7 +442,7 @@ class ThreadView extends GetWidget<ThreadController>
 
   bool _handleScrollNotificationListener(ScrollNotification scrollInfo) {
     if (scrollInfo is ScrollEndNotification &&
-        scrollInfo.metrics.pixels == scrollInfo.metrics.maxScrollExtent &&
+        scrollInfo.metrics.pixels >= scrollInfo.metrics.maxScrollExtent &&
         !controller.loadingMoreStatus.value.isRunning &&
         scrollInfo.metrics.axisDirection == AxisDirection.down
     ) {