[tool/ci] Add minimum supported SDK validation (flutter#7028)

Adds options to `pubspec.yaml` to check that the minimum supported SDK range for Flutter/Dart is at least a given version, to add CI enforcement that we're updating all of our support claims when we update our tested versions (rather than it being something we have to remember to do), and enables it in CI.

As part of enabling it, fixes some violations:
- path_provider_foundation had been temporarily dropped back to 2.10 as part of pushing out a regression fix.
- a number of examples were missing Flutter constraints even though they used Flutter.
- the non-Flutter `plugin_platform_interface` package hadn't been update since I hadn't thought about Dart-only constraints in the past.

Author: stuartmorgan-g

.cirrus.yml

@@ -101,7 +101,9 @@ task:
       always:
         format_script: ./script/tool_runner.sh format --fail-on-change
         license_script: $PLUGIN_TOOL_COMMAND license-check
-        pubspec_script: ./script/tool_runner.sh pubspec-check
+        # The major and minor versions here should match the lowest version
+        # analyzed in legacy_version_analyze.
+        pubspec_script: ./script/tool_runner.sh pubspec-check --min-min-flutter-version=3.0.0 --min-min-dart-version=2.17.0
         readme_script:
           - ./script/tool_runner.sh readme-check
           # Re-run with --require-excerpts, skipping packages that still need
@@ -171,6 +173,7 @@ task:
     - name: legacy_version_analyze
       depends_on: analyze
       matrix:
+        # Change the arguments to pubspec-check when changing these values.
         env:
           CHANNEL: "3.0.5"
           DART_VERSION: "2.17.6"

packages/file_selector/file_selector/example/pubspec.yaml

@@ -6,6 +6,7 @@ version: 1.0.0+1
 
 environment:
   sdk: ">=2.12.0 <3.0.0"
+  flutter: ">=3.0.0"
 
 dependencies:
   file_selector:

packages/file_selector/file_selector_ios/example/pubspec.yaml

@@ -5,6 +5,7 @@ version: 1.0.0
 
 environment:
   sdk: ">=2.14.4 <3.0.0"
+  flutter: ">=3.0.0"
 
 dependencies:
   # The following adds the Cupertino Icons font to your application.
@@ -28,4 +29,4 @@ dev_dependencies:
     sdk: flutter
 
 flutter:
-  uses-material-design: true
+  uses-material-design: true

packages/file_selector/file_selector_linux/example/pubspec.yaml

@@ -5,6 +5,7 @@ version: 1.0.0+1
 
 environment:
   sdk: ">=2.12.0 <3.0.0"
+  flutter: ">=3.0.0"
 
 dependencies:
   file_selector_linux:

packages/flutter_plugin_android_lifecycle/example/pubspec.yaml

@@ -4,6 +4,7 @@ publish_to: none
 
 environment:
   sdk: ">=2.12.0 <3.0.0"
+  flutter: ">=3.0.0"
 
 dependencies:
   flutter:

packages/path_provider/path_provider_foundation/CHANGELOG.md

@@ -1,3 +1,7 @@
+## NEXT
+
+* Updates minimum supported Flutter version to 3.0.
+
 ## 2.1.1
 
 * Fixes a regression in the path retured by `getApplicationSupportDirectory` on iOS.

packages/path_provider/path_provider_foundation/pubspec.yaml

@@ -6,7 +6,7 @@ version: 2.1.1
 
 environment:
   sdk: ">=2.12.0 <3.0.0"
-  flutter: ">=2.10.0"
+  flutter: ">=3.0.0"
 
 flutter:
   plugin:

packages/plugin_platform_interface/CHANGELOG.md

@@ -1,3 +1,7 @@
+## NEXT
+
+* Updates minimum supported Dart version.
+
 ## 2.1.3
 
 * Minor fixes for new analysis options.

packages/plugin_platform_interface/pubspec.yaml

@@ -18,7 +18,7 @@ issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+
 version: 2.1.3
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
+  sdk: ">=2.17.0 <3.0.0"
 
 dependencies:
   meta: ^1.3.0

packages/webview_flutter/webview_flutter_android/example/pubspec.yaml

@@ -4,6 +4,7 @@ publish_to: none
 
 environment:
   sdk: ">=2.14.0 <3.0.0"
+  flutter: ">=3.0.0"
 
 dependencies:
   flutter:

packages/webview_flutter/webview_flutter_web/example/pubspec.yaml

@@ -4,6 +4,7 @@ publish_to: none
 
 environment:
   sdk: ">=2.14.0 <3.0.0"
+  flutter: ">=3.0.0"
 
 dependencies:
   flutter:

packages/webview_flutter/webview_flutter_wkwebview/example/pubspec.yaml

@@ -4,6 +4,7 @@ publish_to: none
 
 environment:
   sdk: ">=2.12.0 <3.0.0"
+  flutter: ">=3.0.0"
 
 dependencies:
   flutter:

script/tool/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.13.4
+
+* Adds the ability to validate minimum supported Dart/Flutter versions in
+  `pubspec-check`.
+
 ## 0.13.3
 
 * Renames `podspecs` to `podspec-check`. The old name will continue to work.

script/tool/lib/src/pubspec_check_command.dart

@@ -5,6 +5,7 @@
 import 'package:file/file.dart';
 import 'package:git/git.dart';
 import 'package:platform/platform.dart';
+import 'package:pub_semver/pub_semver.dart';
 import 'package:yaml/yaml.dart';
 
 import 'common/core.dart';
@@ -29,7 +30,23 @@ class PubspecCheckCommand extends PackageLoopingCommand {
           processRunner: processRunner,
           platform: platform,
           gitDir: gitDir,
-        );
+        ) {
+    argParser.addOption(
+      _minMinDartVersionFlag,
+      help:
+          'The minimum Dart version to allow as the minimum SDK constraint.\n\n'
+          'This is only enforced for non-Flutter packages; Flutter packages '
+          'use --$_minMinFlutterVersionFlag',
+    );
+    argParser.addOption(
+      _minMinFlutterVersionFlag,
+      help:
+          'The minimum Flutter version to allow as the minimum SDK constraint.',
+    );
+  }
+
+  static const String _minMinDartVersionFlag = 'min-min-dart-version';
+  static const String _minMinFlutterVersionFlag = 'min-min-flutter-version';
 
   // Section order for plugins. Because the 'flutter' section is critical
   // information for plugins, and usually small, it goes near the top unlike in
@@ -100,6 +117,24 @@ class PubspecCheckCommand extends PackageLoopingCommand {
       printError('$listIndentation${sectionOrder.join('\n$listIndentation')}');
     }
 
+    final String minMinDartVersionString = getStringArg(_minMinDartVersionFlag);
+    final String minMinFlutterVersionString =
+        getStringArg(_minMinFlutterVersionFlag);
+    final String? minVersionError = _checkForMinimumVersionError(
+      pubspec,
+      package,
+      minMinDartVersion: minMinDartVersionString.isEmpty
+          ? null
+          : Version.parse(minMinDartVersionString),
+      minMinFlutterVersion: minMinFlutterVersionString.isEmpty
+          ? null
+          : Version.parse(minMinFlutterVersionString),
+    );
+    if (minVersionError != null) {
+      printError('$indentation$minVersionError');
+      passing = false;
+    }
+
     if (isPlugin) {
       final String? implementsError =
           _checkForImplementsError(pubspec, package: package);
@@ -320,4 +355,43 @@ class PubspecCheckCommand extends PackageLoopingCommand {
     final String suffix = packageName.substring(parentName.length);
     return !nonImplementationSuffixes.contains(suffix);
   }
+
+  /// Validates that a Flutter package has a minimum SDK version constraint of
+  /// at least [minMinFlutterVersion] (if provided), or that a non-Flutter
+  /// package has a minimum SDK version constraint of [minMinDartVersion]
+  /// (if provided).
+  ///
+  /// Returns an error string if validation fails.
+  String? _checkForMinimumVersionError(
+    Pubspec pubspec,
+    RepositoryPackage package, {
+    Version? minMinDartVersion,
+    Version? minMinFlutterVersion,
+  }) {
+    final VersionConstraint? dartConstraint = pubspec.environment?['sdk'];
+    final VersionConstraint? flutterConstraint =
+        pubspec.environment?['flutter'];
+
+    if (flutterConstraint != null) {
+      // Validate Flutter packages against the Flutter requirement.
+      if (minMinFlutterVersion != null) {
+        final Version? constraintMin =
+            flutterConstraint is VersionRange ? flutterConstraint.min : null;
+        if ((constraintMin ?? Version(0, 0, 0)) < minMinFlutterVersion) {
+          return 'Minimum allowed Flutter version $constraintMin is less than $minMinFlutterVersion';
+        }
+      }
+    } else {
+      // Validate non-Flutter packages against the Dart requirement.
+      if (minMinDartVersion != null) {
+        final Version? constraintMin =
+            dartConstraint is VersionRange ? dartConstraint.min : null;
+        if ((constraintMin ?? Version(0, 0, 0)) < minMinDartVersion) {
+          return 'Minimum allowed Dart version $constraintMin is less than $minMinDartVersion';
+        }
+      }
+    }
+
+    return null;
+  }
 }

script/tool/pubspec.yaml

@@ -1,7 +1,7 @@
 name: flutter_plugin_tools
 description: Productivity utils for flutter/plugins and flutter/packages
 repository: https://github.com/flutter/plugins/tree/main/script/tool
-version: 0.13.3
+version: 0.13.4
 
 dependencies:
   args: ^2.1.0