[_fe_analyzer_shared] Add debugPrint

This adds a `debugPrint` method along with methods to support automatic indentation.

The debug helpers are reexported inside package:analyzer and package:front_end for easy access.

Change-Id: I80a4103e6fb30a6b459551184916c3fa26591a20
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/425280
Commit-Queue: Johnni Winther <[email protected]>
Reviewed-by: Jens Johansen <[email protected]>

Author: johnniwinther

pkg/_fe_analyzer_shared/lib/src/debug_helpers/debug_helpers.dart

@@ -0,0 +1,6 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+export 'print.dart';
+export 'stack_trace.dart';

pkg/_fe_analyzer_shared/lib/src/debug_helpers/print.dart

@@ -0,0 +1,45 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+int _indentLevel = 0;
+
+/// Prints the `toString()` of [value] to stdout.
+///
+/// This supports automatic indentation when used with [debugPrintEnd],
+/// [debugPrintStart] and [inDebugPrint].
+void debugPrint(Object value) {
+  _debugPrint(value);
+}
+
+/// Prints the `toString()` of [value] using [debugPrint] and increases the
+/// indentation level used by [debugPrint].
+void debugPrintEnd(Object value) {
+  _indentLevel--;
+  _debugPrint(value);
+}
+
+/// Decreases the indentation level used by [debugPrint] and prints the
+/// `toString()` of [value] using [debugPrint].
+void debugPrintStart(Object value) {
+  _debugPrint(value);
+  _indentLevel++;
+}
+
+/// Wraps the call to [f] with a start and end message containing the
+/// `toString()` of [value], increasing the indentation level during the call
+/// to [f].
+///
+/// This can be used for easily printing call stacks for debugging.
+void inDebugPrint(Object value, void Function() f) {
+  debugPrintStart('start:$value');
+  try {
+    f();
+  } finally {
+    debugPrintEnd('end  :$value');
+  }
+}
+
+void _debugPrint(Object value) {
+  print('${'  ' * _indentLevel}${value}');
+}

pkg/analyzer/lib/src/debug_helpers.dart

@@ -0,0 +1,6 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Reexport debug helpers to make them easily available inside package:analyzer.
+export 'package:_fe_analyzer_shared/src/debug_helpers/debug_helpers.dart';

pkg/front_end/lib/src/debug_helpers.dart

@@ -0,0 +1,7 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Reexport debug helpers to make them easily available inside
+// package:front_end.
+export 'package:_fe_analyzer_shared/src/debug_helpers/debug_helpers.dart';

pkg/front_end/test/lint_test.status

@@ -2,6 +2,7 @@
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
+_fe_analyzer_shared/lib/src/debug_helpers/debug_helpers/Exports: Fail
 _fe_analyzer_shared/lib/src/metadata/ast/Exports: Fail
 _fe_analyzer_shared/lib/src/parser/parser/Exports: Fail
 _fe_analyzer_shared/lib/src/scanner/scanner/Exports: Fail
@@ -20,6 +21,7 @@ front_end/lib/src/api_prototype/testing/Exports: Fail
 front_end/lib/src/api_prototype/try_constant_evaluator/Exports: Fail
 front_end/lib/src/base/messages/Exports: Fail
 front_end/lib/src/codes/cfe_codes/Exports: Fail
+front_end/lib/src/debug_helpers/Exports: Fail
 front_end/lib/src/testing/id_testing_helper/Exports: Fail
 kernel/lib/ast/Exports: Fail
 kernel/lib/kernel/Exports: Fail

pkg/front_end/test/spell_checking_list_code.txt

@@ -118,6 +118,7 @@ augments
 author
 auto
 automagically
+automatic
 auxiliary
 averages
 awaited
@@ -1485,6 +1486,7 @@ redirections
 redirector
 redo
 reevaluation
+reexport
 reexports
 ref
 refactoring