fixed client-reported crashes in the pdf viewer, image picker and prosemirror images, mapped webdav errors to user messages and hardened keychain, cache and push stores against io failures

test/widget/prosemirror/pm_image_width_test.dart

@@ -0,0 +1,31 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:marianum_mobile/widget/prosemirror/pm_image_view.dart';
+
+void main() {
+  group('resolvePmImageWidth', () {
+    test('returns null without a width attribute', () {
+      expect(resolvePmImageWidth(null, 300), isNull);
+    });
+
+    test('returns null for unparseable widths', () {
+      expect(resolvePmImageWidth('auto', 300), isNull);
+    });
+
+    test('resolves px, %, em and rem', () {
+      expect(resolvePmImageWidth('120px', 300), 120);
+      expect(resolvePmImageWidth('50%', 300), 150);
+      expect(resolvePmImageWidth('2em', 300), 32);
+      expect(resolvePmImageWidth('2rem', 300), 32);
+    });
+
+    test('caps at the available width and floors at one pixel', () {
+      expect(resolvePmImageWidth('900px', 300), 300);
+      expect(resolvePmImageWidth('0px', 300), 1);
+    });
+
+    test('survives zero or sub-pixel available width', () {
+      expect(resolvePmImageWidth('50%', 0), isNull);
+      expect(resolvePmImageWidth('120px', 0.5), isNull);
+    });
+  });
+}

test/widget/route_transition_gate_test.dart

@@ -11,7 +11,12 @@ void main() {
   Widget gatedPage() => Scaffold(
     body: RouteTransitionGate(
       placeholder: const SizedBox(key: placeholder),
-      builder: (_) => const SizedBox(key: gated),
+      // Hit-testable like the real viewer, so pointer tracking sees it.
+      builder: (_) => const ColoredBox(
+        key: gated,
+        color: Color(0x00000000),
+        child: SizedBox.expand(),
+      ),
     ),
   );
 
@@ -29,7 +34,9 @@ void main() {
   ) async {
     await pumpApp(tester);
     unawaited(
-      navigator(tester).push(MaterialPageRoute<void>(builder: (_) => gatedPage())),
+      navigator(
+        tester,
+      ).push(MaterialPageRoute<void>(builder: (_) => gatedPage())),
     );
     await tester.pump();
     await tester.pump(const Duration(milliseconds: 50));
@@ -45,7 +52,9 @@ void main() {
   testWidgets('swaps back to placeholder while the route pops', (tester) async {
     await pumpApp(tester);
     unawaited(
-      navigator(tester).push(MaterialPageRoute<void>(builder: (_) => gatedPage())),
+      navigator(
+        tester,
+      ).push(MaterialPageRoute<void>(builder: (_) => gatedPage())),
     );
     await tester.pumpAndSettle();
     expect(find.byKey(gated), findsOneWidget);
@@ -63,13 +72,17 @@ void main() {
   ) async {
     await pumpApp(tester);
     unawaited(
-      navigator(tester).push(MaterialPageRoute<void>(builder: (_) => gatedPage())),
+      navigator(
+        tester,
+      ).push(MaterialPageRoute<void>(builder: (_) => gatedPage())),
     );
     await tester.pumpAndSettle();
     expect(find.byKey(gated), findsOneWidget);
 
     unawaited(
-      navigator(tester).push(MaterialPageRoute<void>(builder: (_) => const Scaffold())),
+      navigator(
+        tester,
+      ).push(MaterialPageRoute<void>(builder: (_) => const Scaffold())),
     );
     await tester.pump();
     await tester.pump(const Duration(milliseconds: 50));
@@ -84,6 +97,86 @@ void main() {
     expect(find.byKey(placeholder), findsNothing);
   });
 
+  testWidgets('re-gates when the settled subtree moves under a fresh Transform', (
+    tester,
+  ) async {
+    // Android's predictive back moves the route content (GlobalKey) under a
+    // brand-new Transform.scale without any animation status change. The
+    // padding changes the constraints so the moved subtree is laid out nested
+    // under the transform's first layout, which is when `localToGlobal` throws.
+    final subtree = GlobalKey();
+    var wrapped = false;
+    late StateSetter rebuild;
+    await tester.pumpWidget(
+      MaterialApp(
+        home: StatefulBuilder(
+          builder: (context, setState) {
+            rebuild = setState;
+            final child = KeyedSubtree(
+              key: subtree,
+              child: Scaffold(
+                body: RouteTransitionGate(
+                  placeholder: const SizedBox(key: placeholder),
+                  builder: (_) => const _LocalToGlobalProbe(key: gated),
+                ),
+              ),
+            );
+            if (!wrapped) return child;
+            return Padding(
+              padding: const EdgeInsets.all(1),
+              child: Transform.scale(scale: 1, child: child),
+            );
+          },
+        ),
+      ),
+    );
+    await tester.pump();
+    await tester.pump();
+    expect(find.byKey(gated), findsOneWidget);
+
+    rebuild(() => wrapped = true);
+    await tester.pump();
+    expect(tester.takeException(), isNull);
+    expect(find.byKey(placeholder), findsOneWidget);
+
+    await tester.pump();
+    expect(find.byKey(gated), findsOneWidget);
+    expect(tester.takeException(), isNull);
+  });
+
+  testWidgets('keeps the child mounted while a back swipe drives the pop', (
+    tester,
+  ) async {
+    // iOS back swipe: the edge detector is translucent, so the finger that
+    // drives the pop animation is also down on the viewer. Unmounting it now
+    // would route the next pointer move into a disposed State. (A programmatic
+    // pop is harmless — the Navigator cancels active pointers first.)
+    await pumpApp(tester);
+    unawaited(
+      navigator(
+        tester,
+      ).push(MaterialPageRoute<void>(builder: (_) => gatedPage())),
+    );
+    await tester.pumpAndSettle();
+    expect(find.byKey(gated), findsOneWidget);
+
+    final gesture = await tester.startGesture(const Offset(5, 300));
+    await gesture.moveBy(const Offset(60, 0));
+    await tester.pump();
+    await gesture.moveBy(const Offset(60, 0));
+    await tester.pump();
+    // Pop animation is running (status reverse), finger still down.
+    expect(find.byKey(gated), findsOneWidget);
+    expect(find.byKey(placeholder), findsNothing);
+    expect(tester.takeException(), isNull);
+
+    await gesture.up();
+    await tester.pump();
+    expect(find.byKey(gated), findsNothing);
+    await tester.pumpAndSettle();
+    expect(tester.takeException(), isNull);
+  }, variant: TargetPlatformVariant.only(TargetPlatform.iOS));
+
   testWidgets('holds the child back for one frame without a route animation', (
     tester,
   ) async {
@@ -99,3 +192,25 @@ void main() {
     expect(find.byKey(placeholder), findsNothing);
   });
 }
+
+/// Mimics SfPdfViewer: a stateful widget whose LayoutBuilder resolves a
+/// child's global position during layout.
+class _LocalToGlobalProbe extends StatefulWidget {
+  const _LocalToGlobalProbe({super.key});
+
+  @override
+  State<_LocalToGlobalProbe> createState() => _LocalToGlobalProbeState();
+}
+
+class _LocalToGlobalProbeState extends State<_LocalToGlobalProbe> {
+  final _viewport = GlobalKey();
+
+  @override
+  Widget build(BuildContext context) => LayoutBuilder(
+    builder: (context, constraints) {
+      final box = _viewport.currentContext?.findRenderObject() as RenderBox?;
+      if (box != null && box.hasSize) box.localToGlobal(Offset.zero);
+      return SizedBox.expand(key: _viewport);
+    },
+  );
+}