Style: Rename pageBuilder with builder in showCupertinoSheet (#170625)

Style: Rename pageBuilder with builder in showCupertinoSheet
fixes: #169831

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

packages/flutter/lib/fix_data/fix_cupertino.yaml

@@ -428,4 +428,27 @@ transforms:
       minSize:
         kind: fragment
         value: 'arguments[minSize]'
+
+  # Changes made in https://github.com/flutter/flutter/pull/170625
+  - title: "Migrate to 'builder'"
+    date: 2025-06-14
+    element:
+      uris: [ 'cupertino.dart' ]
+      function: 'showCupertinoSheet'
+    oneOf:
+      - if: "pageBuilder != ''"
+        changes:
+          - kind: 'addParameter'
+            index: 3
+            name: 'builder'
+            style: optional_named
+            argumentValue:
+              expression: '{% pageBuilder %}'
+              requiredIf: "pageBuilder != ''"
+          - kind: 'removeParameter'
+            name: 'pageBuilder'
+    variables:
+      pageBuilder:
+        kind: fragment
+        value: 'arguments[pageBuilder]'
 # Before adding a new fix: read instructions at the top of this file.

packages/flutter/lib/src/cupertino/sheet.dart

@@ -140,16 +140,24 @@ final Animatable<double> _kScaleTween = Tween<double>(begin: 1.0, end: 1.0 - _kS
 ///  * <https://developer.apple.com/design/human-interface-guidelines/sheets>
 Future<T?> showCupertinoSheet<T>({
   required BuildContext context,
-  required WidgetBuilder pageBuilder,
+  @Deprecated(
+    'Use builder instead. '
+    'This feature was deprecated after v3.33.0-0.2.pre.',
+  )
+  WidgetBuilder? pageBuilder,
+  WidgetBuilder? builder,
   bool useNestedNavigation = false,
   bool enableDrag = true,
 }) {
-  final WidgetBuilder builder;
+  assert(pageBuilder != null || builder != null);
+
+  final WidgetBuilder? effectivePageBuilder = builder ?? pageBuilder;
+  final WidgetBuilder widgetBuilder;
   final GlobalKey<NavigatorState> nestedNavigatorKey = GlobalKey<NavigatorState>();
   if (!useNestedNavigation) {
-    builder = pageBuilder;
+    widgetBuilder = effectivePageBuilder!;
   } else {
-    builder = (BuildContext context) {
+    widgetBuilder = (BuildContext context) {
       return NavigatorPopHandler(
         onPopWithResult: (T? result) {
           nestedNavigatorKey.currentState!.maybePop();
@@ -169,7 +177,7 @@ Future<T?> showCupertinoSheet<T>({
                       }
                       Navigator.of(context, rootNavigator: true).pop(result);
                     },
-                    child: pageBuilder(context),
+                    child: effectivePageBuilder!(context),
                   );
                 },
               ),
@@ -183,7 +191,7 @@ Future<T?> showCupertinoSheet<T>({
   return Navigator.of(
     context,
     rootNavigator: true,
-  ).push<T>(CupertinoSheetRoute<T>(builder: builder, enableDrag: enableDrag));
+  ).push<T>(CupertinoSheetRoute<T>(builder: widgetBuilder, enableDrag: enableDrag));
 }
 
 /// Provides an iOS-style sheet transition.

packages/flutter/test_fixes/cupertino/cupertino.dart

@@ -289,4 +289,10 @@ void main() {
 
   // https://github.com/flutter/flutter/pull/161295
   CupertinoButton(minSize: 60.0);
+
+  // https://github.com/flutter/flutter/pull/170625
+  showCupertinoSheet(
+    context: context,
+    pageBuilder: (BuildContext context) => Container(),
+  );
 }

packages/flutter/test_fixes/cupertino/cupertino.dart.expect

@@ -307,4 +307,10 @@ void main() {
 
   // https://github.com/flutter/flutter/pull/161295
   CupertinoButton(minimumSize: Size(60.0, 60.0));
+
+  // https://github.com/flutter/flutter/pull/170625
+  showCupertinoSheet(
+    context: context,
+    builder: (BuildContext context) => Container(),
+  );
 }