Extend validation for cycles to other packages than dartpad_ui (#3344)

* -

* Update CONTRIBUTING.md

Author: polina-c

.github/workflows/dart_services.yml

@@ -50,3 +50,5 @@ jobs:
 
       - name: Run tests
         run: dart test test/presubmit
+
+      - run: sh ./tool/check_cycles.sh

.github/workflows/dartpad_shared.yml

@@ -36,3 +36,5 @@ jobs:
 
       - name: Analyze project source
         run: dart analyze --fatal-infos
+
+      - run: sh ./tool/check_cycles.sh

.github/workflows/samples.yml

@@ -30,3 +30,4 @@ jobs:
       - run: dart format --set-exit-if-changed .
       - run: dart tool/samples.dart --verify
       - run: flutter build web
+      - run: sh ./tool/check_cycles.sh

CONTRIBUTING.md

@@ -57,7 +57,7 @@ dependencies because of other reasons, this is how you can
 generate dependency diagrams:
 
 ```
-cd pkgs/dartpad_ui
+cd pkgs/<the package>
 dart pub global activate layerlens
 layerlens
 ```

pkgs/dart_services/tool/check_cycles.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+# Copyright 2025 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+
+# Fast fail the script on failures.
+set -ex
+
+# The directory that this script is located in.
+TOOL_DIR=`dirname "$0"`
+
+dart pub global activate layerlens
+layerlens --path $TOOL_DIR/.. --fail-on-cycles

pkgs/dartpad_shared/tool/check_cycles.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+# Copyright 2025 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+
+# Fast fail the script on failures.
+set -ex
+
+# The directory that this script is located in.
+TOOL_DIR=`dirname "$0"`
+
+dart pub global activate layerlens
+layerlens --path $TOOL_DIR/.. --fail-on-cycles

pkgs/samples/tool/check_cycles.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+# Copyright 2025 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+
+# Fast fail the script on failures.
+set -ex
+
+# The directory that this script is located in.
+TOOL_DIR=`dirname "$0"`
+
+dart pub global activate layerlens
+layerlens --path $TOOL_DIR/.. --fail-on-cycles