[tools] Improves version-check logic (#6354)

Improves the logic used to determine whether to require a version and/or CHANGELOG change:
- Removes the requirement that dev-only (e.g., test) changes update the CHANGELOG, since in practice we were essentially always overriding in that case.
- Adds file-level analysis of `build.gradle` files to determine whether they are only changing test dependencies.
- Improves the "is this a published example file" logic to better match pub.dev's logic, to fix some false positives and false negatives (e.g., `rfw`'s `example/<foo>/lib/main.dart` being considered published).

Removes the no-longer-necessary special-case handling of some Dependabot PRs, as well as the PR-description-based system it was built on (and that turned out not to be very useful due to the way `CIRRUS_CHANGE_MESSAGE` actually worked). `build.gradle` analysis should not cover all such cases, and without the need to hard-code them by package name.

script/tool/test/common/package_state_utils_test.dart

@@ -3,7 +3,9 @@
 // found in the LICENSE file.
 import 'package:file/file.dart';
 import 'package:file/memory.dart';
+import 'package:flutter_plugin_tools/src/common/git_version_finder.dart';
 import 'package:flutter_plugin_tools/src/common/package_state_utils.dart';
+import 'package:test/fake.dart';
 import 'package:test/test.dart';
 
 import '../util.dart';
@@ -26,12 +28,13 @@ void main() {
         'packages/a_package/lib/plugin.dart',
       ];
 
-      final PackageChangeState state = checkPackageChangeState(package,
+      final PackageChangeState state = await checkPackageChangeState(package,
           changedPaths: changedFiles,
           relativePackagePath: 'packages/a_package');
 
       expect(state.hasChanges, true);
       expect(state.needsVersionChange, true);
+      expect(state.needsChangelogChange, true);
     });
 
     test('handles trailing slash on package path', () async {
@@ -42,16 +45,18 @@ void main() {
         'packages/a_package/lib/plugin.dart',
       ];
 
-      final PackageChangeState state = checkPackageChangeState(package,
+      final PackageChangeState state = await checkPackageChangeState(package,
           changedPaths: changedFiles,
           relativePackagePath: 'packages/a_package/');
 
       expect(state.hasChanges, true);
       expect(state.needsVersionChange, true);
+      expect(state.needsChangelogChange, true);
       expect(state.hasChangelogChange, false);
     });
 
-    test('does not report version change exempt changes', () async {
+    test('does not flag version- and changelog-change-exempt changes',
+        () async {
       final RepositoryPackage package =
           createFakePlugin('a_plugin', packagesDir);
 
@@ -64,12 +69,13 @@ void main() {
         'packages/a_plugin/CHANGELOG.md',
       ];
 
-      final PackageChangeState state = checkPackageChangeState(package,
+      final PackageChangeState state = await checkPackageChangeState(package,
           changedPaths: changedFiles,
           relativePackagePath: 'packages/a_plugin/');
 
       expect(state.hasChanges, true);
       expect(state.needsVersionChange, false);
+      expect(state.needsChangelogChange, false);
       expect(state.hasChangelogChange, true);
     });
 
@@ -81,28 +87,49 @@ void main() {
         'packages/a_plugin/lib/foo/tool/tool_thing.dart',
       ];
 
-      final PackageChangeState state = checkPackageChangeState(package,
+      final PackageChangeState state = await checkPackageChangeState(package,
           changedPaths: changedFiles,
           relativePackagePath: 'packages/a_plugin/');
 
       expect(state.hasChanges, true);
       expect(state.needsVersionChange, true);
+      expect(state.needsChangelogChange, true);
     });
 
-    test('requires a version change for example main', () async {
-      final RepositoryPackage package =
-          createFakePlugin('a_plugin', packagesDir);
+    test('requires a version change for example/lib/main.dart', () async {
+      final RepositoryPackage package = createFakePlugin(
+          'a_plugin', packagesDir,
+          extraFiles: <String>['example/lib/main.dart']);
 
       const List<String> changedFiles = <String>[
         'packages/a_plugin/example/lib/main.dart',
       ];
 
-      final PackageChangeState state = checkPackageChangeState(package,
+      final PackageChangeState state = await checkPackageChangeState(package,
           changedPaths: changedFiles,
           relativePackagePath: 'packages/a_plugin/');
 
       expect(state.hasChanges, true);
       expect(state.needsVersionChange, true);
+      expect(state.needsChangelogChange, true);
+    });
+
+    test('requires a version change for example/main.dart', () async {
+      final RepositoryPackage package = createFakePlugin(
+          'a_plugin', packagesDir,
+          extraFiles: <String>['example/main.dart']);
+
+      const List<String> changedFiles = <String>[
+        'packages/a_plugin/example/main.dart',
+      ];
+
+      final PackageChangeState state = await checkPackageChangeState(package,
+          changedPaths: changedFiles,
+          relativePackagePath: 'packages/a_plugin/');
+
+      expect(state.hasChanges, true);
+      expect(state.needsVersionChange, true);
+      expect(state.needsChangelogChange, true);
     });
 
     test('requires a version change for example readme.md', () async {
@@ -113,28 +140,189 @@ void main() {
         'packages/a_plugin/example/README.md',
       ];
 
-      final PackageChangeState state = checkPackageChangeState(package,
+      final PackageChangeState state = await checkPackageChangeState(package,
           changedPaths: changedFiles,
           relativePackagePath: 'packages/a_plugin/');
 
       expect(state.hasChanges, true);
       expect(state.needsVersionChange, true);
+      expect(state.needsChangelogChange, true);
     });
 
-    test('requires a version change for example example.md', () async {
+    test('requires a version change for example/example.md', () async {
+      final RepositoryPackage package = createFakePlugin(
+          'a_plugin', packagesDir,
+          extraFiles: <String>['example/example.md']);
+
+      const List<String> changedFiles = <String>[
+        'packages/a_plugin/example/example.md',
+      ];
+
+      final PackageChangeState state = await checkPackageChangeState(package,
+          changedPaths: changedFiles,
+          relativePackagePath: 'packages/a_plugin/');
+
+      expect(state.hasChanges, true);
+      expect(state.needsVersionChange, true);
+      expect(state.needsChangelogChange, true);
+    });
+
+    test(
+        'requires a changelog change but no version change for '
+        'lower-priority examples when example.md is present', () async {
+      final RepositoryPackage package = createFakePlugin(
+          'a_plugin', packagesDir,
+          extraFiles: <String>['example/example.md']);
+
+      const List<String> changedFiles = <String>[
+        'packages/a_plugin/example/lib/main.dart',
+        'packages/a_plugin/example/main.dart',
+        'packages/a_plugin/example/README.md',
+      ];
+
+      final PackageChangeState state = await checkPackageChangeState(package,
+          changedPaths: changedFiles,
+          relativePackagePath: 'packages/a_plugin/');
+
+      expect(state.hasChanges, true);
+      expect(state.needsVersionChange, false);
+      expect(state.needsChangelogChange, true);
+    });
+
+    test(
+        'requires a changelog change but no version change for README.md when '
+        'code example is present', () async {
+      final RepositoryPackage package = createFakePlugin(
+          'a_plugin', packagesDir,
+          extraFiles: <String>['example/lib/main.dart']);
+
+      const List<String> changedFiles = <String>[
+        'packages/a_plugin/example/README.md',
+      ];
+
+      final PackageChangeState state = await checkPackageChangeState(package,
+          changedPaths: changedFiles,
+          relativePackagePath: 'packages/a_plugin/');
+
+      expect(state.hasChanges, true);
+      expect(state.needsVersionChange, false);
+      expect(state.needsChangelogChange, true);
+    });
+
+    test(
+        'does not requires changelog or version change for build.gradle '
+        'test-dependency-only changes', () async {
       final RepositoryPackage package =
           createFakePlugin('a_plugin', packagesDir);
 
       const List<String> changedFiles = <String>[
-        'packages/a_plugin/example/lib/example.md',
+        'packages/a_plugin/android/build.gradle',
       ];
 
-      final PackageChangeState state = checkPackageChangeState(package,
+      final GitVersionFinder git = FakeGitVersionFinder(<String, List<String>>{
+        'packages/a_plugin/android/build.gradle': <String>[
+          "-  androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'",
+          "-  testImplementation 'junit:junit:4.10.0'",
+          "+  androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'",
+          "+  testImplementation 'junit:junit:4.13.2'",
+        ]
+      });
+
+      final PackageChangeState state = await checkPackageChangeState(package,
+          changedPaths: changedFiles,
+          relativePackagePath: 'packages/a_plugin/',
+          git: git);
+
+      expect(state.hasChanges, true);
+      expect(state.needsVersionChange, false);
+      expect(state.needsChangelogChange, false);
+    });
+
+    test('requires changelog or version change for other build.gradle changes',
+        () async {
+      final RepositoryPackage package =
+          createFakePlugin('a_plugin', packagesDir);
+
+      const List<String> changedFiles = <String>[
+        'packages/a_plugin/android/build.gradle',
+      ];
+
+      final GitVersionFinder git = FakeGitVersionFinder(<String, List<String>>{
+        'packages/a_plugin/android/build.gradle': <String>[
+          "-  androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'",
+          "-  testImplementation 'junit:junit:4.10.0'",
+          "+  androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'",
+          "+  testImplementation 'junit:junit:4.13.2'",
+          "-  implementation 'com.google.android.gms:play-services-maps:18.0.0'",
+          "+  implementation 'com.google.android.gms:play-services-maps:18.0.2'",
+        ]
+      });
+
+      final PackageChangeState state = await checkPackageChangeState(package,
+          changedPaths: changedFiles,
+          relativePackagePath: 'packages/a_plugin/',
+          git: git);
+
+      expect(state.hasChanges, true);
+      expect(state.needsVersionChange, true);
+      expect(state.needsChangelogChange, true);
+    });
+
+    test(
+        'requires changelog or version change if build.gradle diffs cannot '
+        'be checked', () async {
+      final RepositoryPackage package =
+          createFakePlugin('a_plugin', packagesDir);
+
+      const List<String> changedFiles = <String>[
+        'packages/a_plugin/android/build.gradle',
+      ];
+
+      final PackageChangeState state = await checkPackageChangeState(package,
           changedPaths: changedFiles,
           relativePackagePath: 'packages/a_plugin/');
 
       expect(state.hasChanges, true);
       expect(state.needsVersionChange, true);
+      expect(state.needsChangelogChange, true);
+    });
+
+    test(
+        'requires changelog or version change if build.gradle diffs cannot '
+        'be determined', () async {
+      final RepositoryPackage package =
+          createFakePlugin('a_plugin', packagesDir);
+
+      const List<String> changedFiles = <String>[
+        'packages/a_plugin/android/build.gradle',
+      ];
+
+      final GitVersionFinder git = FakeGitVersionFinder(<String, List<String>>{
+        'packages/a_plugin/android/build.gradle': <String>[]
+      });
+
+      final PackageChangeState state = await checkPackageChangeState(package,
+          changedPaths: changedFiles,
+          relativePackagePath: 'packages/a_plugin/',
+          git: git);
+
+      expect(state.hasChanges, true);
+      expect(state.needsVersionChange, true);
+      expect(state.needsChangelogChange, true);
     });
   });
 }
+
+class FakeGitVersionFinder extends Fake implements GitVersionFinder {
+  FakeGitVersionFinder(this.fileDiffs);
+
+  final Map<String, List<String>> fileDiffs;
+
+  @override
+  Future<List<String>> getDiffContents({
+    String? targetPath,
+    bool includeUncommitted = false,
+  }) async {
+    return fileDiffs[targetPath]!;
+  }
+}