chore: adopt Dart 3.9 toolchain — honest floor + tall-style reformat (T-353)

Raise the declared minimums in pubspec.yaml to what our deps already
require: Flutter >=3.35.0 / Dart >=3.9.0 (was 3.19.0 / 3.5.0). alchemist
0.12 needs Flutter 3.32; Dart 3.9 first ships in Flutter 3.35, so 3.35 is
the binding floor. Pin the exact build toolchain in .fvmrc (Flutter
3.44.1).

Moving to the Dart 3.9 language level switches `dart format` to the new
"tall" style and enables two new lints. This commit is the resulting
mechanical churn, isolated from any behaviour change:
  - whole-tree `dart format` reformat (tall style)
  - `dart fix` for unnecessary_underscores + use_null_aware_elements

No runtime behaviour change; `make test` green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

test/builtin/editor/editor_controller_test.dart

@@ -15,12 +15,12 @@ IpcResponse _ok(Map<String, Object?> data) => IpcResponse.ok(id: '', data: data)
 Map<String, Object?> _buf(String id, String path, {bool dirty = false}) => {'id': id, 'path': path, 'dirty': dirty};
 
 Map<String, Object?> _read(String id, String path, String content, {bool dirty = false}) => {
-      'id': id,
-      'path': path,
-      'content': content,
-      'selection': {'start': 0, 'end': 0},
-      'dirty': dirty,
-    };
+  'id': id,
+  'path': path,
+  'content': content,
+  'selection': {'start': 0, 'end': 0},
+  'dirty': dirty,
+};
 
 void emitEditor(DaemonBus bus, String kind, Map<String, Object?> data) {
   bus.emit(DaemonEvent(subsystem: 'editor', kind: kind, data: data, ts: DateTime.now().toUtc()));
@@ -45,15 +45,17 @@ void main() {
   group('hydrate', () {
     test('populates the open-buffer list and loads the active buffer', () async {
       ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': [_buf('b_1', 'lib/a.dart'), _buf('b_2', 'lib/b.dart', dirty: true)]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': [_buf('b_1', 'lib/a.dart'), _buf('b_2', 'lib/b.dart', dirty: true)],
+        }),
+      );
       ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       ipc.stub('editor.read', (a) async => _ok(_read('b_1', 'lib/a.dart', 'hello')));
 
       await c.hydrate();
@@ -66,10 +68,11 @@ void main() {
 
     test('with no active buffer leaves the list but no active content', () async {
       ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': [_buf('b_1', 'lib/a.dart')]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': [_buf('b_1', 'lib/a.dart')],
+        }),
+      );
       ipc.stub('editor.active', (_) async => _ok(const {})); // no `active` key
 
       await c.hydrate();
@@ -93,15 +96,17 @@ void main() {
 
     test('activate is a no-op when the id is already active', () async {
       ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': [_buf('b_1', 'a.dart')]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': [_buf('b_1', 'a.dart')],
+        }),
+      );
       ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       ipc.stub('editor.read', (_) async => _ok(_read('b_1', 'a.dart', 'x')));
       await c.hydrate();
 
@@ -129,15 +134,17 @@ void main() {
     test('editor.opened refreshes the list and loads the new active buffer', () async {
       var listVersion = 1;
       ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': listVersion == 1 ? [_buf('b_1', 'a.dart')] : [_buf('b_1', 'a.dart'), _buf('b_2', 'b.dart')]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': listVersion == 1 ? [_buf('b_1', 'a.dart')] : [_buf('b_1', 'a.dart'), _buf('b_2', 'b.dart')],
+        }),
+      );
       ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       ipc.stub('editor.read', (a) async {
         final id = a['id'] as String;
         return _ok(_read(id, id == 'b_1' ? 'a.dart' : 'b.dart', 'content-$id'));
@@ -157,15 +164,17 @@ void main() {
     test('editor.closed refreshes the list and clears active when it was active', () async {
       var listVersion = 1;
       ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': listVersion == 1 ? [_buf('b_1', 'a.dart'), _buf('b_2', 'b.dart')] : [_buf('b_2', 'b.dart')]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': listVersion == 1 ? [_buf('b_1', 'a.dart'), _buf('b_2', 'b.dart')] : [_buf('b_2', 'b.dart')],
+        }),
+      );
       ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       ipc.stub('editor.read', (a) async => _ok(_read(a['id'] as String, 'a.dart', 'x')));
       await c.hydrate();
       expect(c.buffers, hasLength(2));
@@ -180,15 +189,17 @@ void main() {
 
     test('editor.saved clears the dirty marker on the buffer', () async {
       ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': [_buf('b_1', 'a.dart', dirty: true)]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': [_buf('b_1', 'a.dart', dirty: true)],
+        }),
+      );
       ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       ipc.stub('editor.read', (_) async => _ok(_read('b_1', 'a.dart', 'x', dirty: true)));
       await c.hydrate();
       expect(c.buffers.single.dirty, isTrue);
@@ -202,15 +213,17 @@ void main() {
 
     test('editor.edited marks the right buffer dirty, leaving siblings alone', () async {
       ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': [_buf('b_1', 'a.dart'), _buf('b_2', 'b.dart')]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': [_buf('b_1', 'a.dart'), _buf('b_2', 'b.dart')],
+        }),
+      );
       ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       ipc.stub('editor.read', (a) async => _ok(_read(a['id'] as String, 'a.dart', 'x')));
       await c.hydrate();
       expect(c.buffers.every((b) => !b.dirty), isTrue);
@@ -226,15 +239,17 @@ void main() {
 
     test('editor.active-changed to a different buffer loads its content', () async {
       ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': [_buf('b_1', 'a.dart'), _buf('b_2', 'b.dart')]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': [_buf('b_1', 'a.dart'), _buf('b_2', 'b.dart')],
+        }),
+      );
       ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       ipc.stub('editor.read', (a) async {
         final id = a['id'] as String;
         return _ok(_read(id, id == 'b_1' ? 'a.dart' : 'b.dart', 'body-$id'));
@@ -253,15 +268,17 @@ void main() {
   group('local edits', () {
     test('pushLocalEdit marks the active buffer dirty and mirrors to IPC', () async {
       ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': [_buf('b_1', 'a.dart')]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': [_buf('b_1', 'a.dart')],
+        }),
+      );
       ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       ipc.stub('editor.read', (_) async => _ok(_read('b_1', 'a.dart', 'x')));
       await c.hydrate();
 
@@ -281,15 +298,17 @@ void main() {
 
     test('save() issues editor.save for the active buffer', () async {
       ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': [_buf('b_1', 'a.dart')]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': [_buf('b_1', 'a.dart')],
+        }),
+      );
       ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       ipc.stub('editor.read', (_) async => _ok(_read('b_1', 'a.dart', 'x')));
       await c.hydrate();
 
@@ -316,15 +335,17 @@ void main() {
   group('edge cases', () {
     test('editor.active-changed to null clears the active buffer', () async {
       ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': [_buf('b_1', 'a.dart')]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': [_buf('b_1', 'a.dart')],
+        }),
+      );
       ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       ipc.stub('editor.read', (_) async => _ok(_read('b_1', 'a.dart', 'x')));
       await c.hydrate();
       expect(c.activeId, 'b_1');
@@ -358,15 +379,17 @@ void main() {
 
     test('editor.opened with no id clears the active buffer', () async {
       ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': [_buf('b_1', 'a.dart')]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': [_buf('b_1', 'a.dart')],
+        }),
+      );
       ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       ipc.stub('editor.read', (_) async => _ok(_read('b_1', 'a.dart', 'x')));
       await c.hydrate();
       expect(c.activeId, 'b_1');
@@ -378,15 +401,17 @@ void main() {
 
     test('a failing editor.read surfaces the error', () async {
       ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': [_buf('b_1', 'a.dart')]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': [_buf('b_1', 'a.dart')],
+        }),
+      );
       ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       ipc.stub(
         'editor.read',
         (_) async => IpcResponse.err(
@@ -400,15 +425,17 @@ void main() {
 
     test('our own edit echo (editor.edited) is suppressed once, not reloaded', () async {
       ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': [_buf('b_1', 'a.dart')]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': [_buf('b_1', 'a.dart')],
+        }),
+      );
       ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       ipc.stub('editor.read', (_) async => _ok(_read('b_1', 'a.dart', 'original')));
       ipc.stub('editor.set-content', (_) async => _ok(const {}));
       await c.hydrate();
@@ -433,15 +460,17 @@ void main() {
   group('editor settings (T-29)', () {
     Future<void> hydrateWith(Map<String, Object?> read) async {
       ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': [_buf('b_1', 'lib/a.dart')]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': [_buf('b_1', 'lib/a.dart')],
+        }),
+      );
       ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       ipc.stub('editor.read', (_) async => _ok(read));
       await c.hydrate();
     }

test/builtin/editor/editor_view_test.dart

@@ -21,13 +21,13 @@ IpcResponse _ok(Map<String, Object?> data) => IpcResponse.ok(id: '', data: data)
 Map<String, Object?> _buf(String id, String path, {bool dirty = false}) => {'id': id, 'path': path, 'dirty': dirty};
 
 Map<String, Object?> _read(String id, String path, {Map<String, Object?>? settings}) => {
-      'id': id,
-      'path': path,
-      'content': 'content of $path',
-      'selection': {'start': 0, 'end': 0},
-      'dirty': false,
-      if (settings != null) 'editorSettings': settings,
-    };
+  'id': id,
+  'path': path,
+  'content': 'content of $path',
+  'selection': {'start': 0, 'end': 0},
+  'dirty': false,
+  'editorSettings': ?settings,
+};
 
 Finder _ruler() => find.byWidgetPredicate((w) => w is CustomPaint && w.painter?.runtimeType.toString() == '_RulerPainter');
 
@@ -40,12 +40,13 @@ void main() {
     void stubBuffers(List<Map<String, Object?>> buffers, {String? active}) {
       f.ipc.stub('editor.list', (_) async => _ok({'buffers': buffers}));
       f.ipc.stub(
-          'editor.active',
-          (_) async => active == null
-              ? _ok(const {})
-              : _ok({
-                  'active': {'id': active}
-                }));
+        'editor.active',
+        (_) async => active == null
+            ? _ok(const {})
+            : _ok({
+                'active': {'id': active},
+              }),
+      );
       f.ipc.stub('editor.read', (a) async {
         final id = a['id'] as String;
         final b = buffers.firstWhere((b) => b['id'] == id);
@@ -147,15 +148,17 @@ void main() {
 
     void stubOne(String path, {Map<String, Object?>? settings}) {
       f.ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': [_buf('b_1', path)]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': [_buf('b_1', path)],
+        }),
+      );
       f.ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       f.ipc.stub('editor.read', (_) async => _ok(_read('b_1', path, settings: settings)));
     }
 
@@ -178,25 +181,28 @@ void main() {
 
     void stubReadContent(String path, String content, Map<String, Object?> settings) {
       f.ipc.stub(
-          'editor.list',
-          (_) async => _ok({
-                'buffers': [_buf('b_1', path)]
-              }));
+        'editor.list',
+        (_) async => _ok({
+          'buffers': [_buf('b_1', path)],
+        }),
+      );
       f.ipc.stub(
-          'editor.active',
-          (_) async => _ok({
-                'active': {'id': 'b_1'}
-              }));
+        'editor.active',
+        (_) async => _ok({
+          'active': {'id': 'b_1'},
+        }),
+      );
       f.ipc.stub(
-          'editor.read',
-          (_) async => _ok({
-                'id': 'b_1',
-                'path': path,
-                'content': content,
-                'selection': {'start': 0, 'end': 0},
-                'dirty': false,
-                'editorSettings': settings
-              }));
+        'editor.read',
+        (_) async => _ok({
+          'id': 'b_1',
+          'path': path,
+          'content': content,
+          'selection': {'start': 0, 'end': 0},
+          'dirty': false,
+          'editorSettings': settings,
+        }),
+      );
       f.ipc.stub('editor.set-content', (_) async => _ok(const {}));
     }
 

test/builtin/editor/syntax_text_controller_test.dart

@@ -41,26 +41,30 @@ void main() {
 
     /// Pump a themed context, run [body] with a controller already
     /// given tokens from the active theme.
-    Future<void> withController(
-      WidgetTester tester,
-      SyntaxTextController c,
-      Future<void> Function(BuildContext ctx) body,
-    ) async {
+    Future<void> withController(WidgetTester tester, SyntaxTextController c, Future<void> Function(BuildContext ctx) body) async {
       late BuildContext ctx;
-      await tester.pumpWidget(harness(f, Builder(builder: (context) {
-        ctx = context;
-        return const SizedBox();
-      })));
+      await tester.pumpWidget(
+        harness(
+          f,
+          Builder(
+            builder: (context) {
+              ctx = context;
+              return const SizedBox();
+            },
+          ),
+        ),
+      );
       c.tokens = ClideTheme.of(ctx).surface;
       await body(ctx);
     }
 
     testWidgets('renders highlighted spans as styled TextSpan children', (tester) async {
       final c = SyntaxTextController(
-          syntax: _FakeSyntax(const [
-        SyntaxSpan(start: 0, end: 5, role: 'keyword'), // "class"
-        SyntaxSpan(start: 6, end: 9, role: 'type'), // "Foo"
-      ]));
+        syntax: _FakeSyntax(const [
+          SyntaxSpan(start: 0, end: 5, role: 'keyword'), // "class"
+          SyntaxSpan(start: 6, end: 9, role: 'type'), // "Foo"
+        ]),
+      );
       await withController(tester, c, (ctx) async {
         c.text = 'class Foo {}';
         c.updatePath('a.dart');
@@ -76,9 +80,10 @@ void main() {
       // '😀' is a surrogate pair (4 UTF-8 bytes). A span after it must
       // still land on the right character offset.
       final c = SyntaxTextController(
-          syntax: _FakeSyntax(const [
-        SyntaxSpan(start: 5, end: 8, role: 'type'), // "Foo" after "😀 "
-      ]));
+        syntax: _FakeSyntax(const [
+          SyntaxSpan(start: 5, end: 8, role: 'type'), // "Foo" after "😀 "
+        ]),
+      );
       await withController(tester, c, (ctx) async {
         c.text = '😀 Foo';
         c.updatePath('a.dart');

test/builtin/editor/vim_edit_ops_test.dart

@@ -8,9 +8,9 @@ import 'package:flutter/services.dart' show TextEditingValue, TextSelection;
 import 'package:flutter_test/flutter_test.dart';
 
 TextEditingValue _tev(String text, int caret, {int? anchor}) => TextEditingValue(
-      text: text,
-      selection: TextSelection(baseOffset: anchor ?? caret, extentOffset: caret),
-    );
+  text: text,
+  selection: TextSelection(baseOffset: anchor ?? caret, extentOffset: caret),
+);
 
 void main() {
   group('motions', () {

test/builtin/editor/vim_editor_test.dart

@@ -22,26 +22,29 @@ void main() {
 
   void stubOneBuffer(String content) {
     f.ipc.stub(
-        'editor.list',
-        (_) async => _ok({
-              'buffers': [
-                {'id': 'b_1', 'path': 'lib/a.dart', 'dirty': false}
-              ]
-            }));
+      'editor.list',
+      (_) async => _ok({
+        'buffers': [
+          {'id': 'b_1', 'path': 'lib/a.dart', 'dirty': false},
+        ],
+      }),
+    );
     f.ipc.stub(
-        'editor.active',
-        (_) async => _ok({
-              'active': {'id': 'b_1'}
-            }));
+      'editor.active',
+      (_) async => _ok({
+        'active': {'id': 'b_1'},
+      }),
+    );
     f.ipc.stub(
-        'editor.read',
-        (_) async => _ok({
-              'id': 'b_1',
-              'path': 'lib/a.dart',
-              'content': content,
-              'selection': {'start': 0, 'end': 0},
-              'dirty': false,
-            }));
+      'editor.read',
+      (_) async => _ok({
+        'id': 'b_1',
+        'path': 'lib/a.dart',
+        'content': content,
+        'selection': {'start': 0, 'end': 0},
+        'dirty': false,
+      }),
+    );
   }
 
   Future<void> pumpEditor(WidgetTester tester) async {