Allow reverts when checking versions

script/tool/CHANGELOG.md

@@ -1,3 +1,9 @@
+## 0.1.3
+
+- Cosmetic fix to `publish-check` output
+- Add a --dart-sdk option to `analyze`
+- Allow reverts in `version-check`
+
 ## 0.1.2
 
 - Add `against-pub` flag for version-check, which allows the command to check version with pub.

script/tool/lib/src/version_check_command.dart

@@ -179,6 +179,20 @@ ${indentation}HTTP response: ${pubVersionFinderResponse.httpResponse.body}
         continue;
       }
 
+      // Check for reverts when doing local validation.
+      if (!getBoolArg(_againstPubFlag) && headVersion < sourceVersion) {
+        final Map<Version, NextVersionType> possibleVersionsFromNewVersion =
+            getAllowedNextVersions(headVersion, sourceVersion);
+        // Since this skips validation, try to ensure that it really is likely
+        // to be a revert rather than a typo by checking that the transition
+        // from the lower version to the new version would have been valid.
+        if (possibleVersionsFromNewVersion.containsKey(sourceVersion)) {
+          print('${indentation}New version is lower than previous version. '
+              'This is assumed to be a revert.');
+          continue;
+        }
+      }
+
       final Map<Version, NextVersionType> allowedNextVersions =
           getAllowedNextVersions(sourceVersion, headVersion);
 

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/master/script/tool
-version: 0.1.2
+version: 0.1.3
 
 dependencies:
   args: ^2.1.0

script/tool/test/version_check_test.dart

@@ -187,6 +187,40 @@ void main() {
       );
     });
 
+    test('allows likely reverts.', () async {
+      createFakePlugin('plugin', includeChangeLog: true, includeVersion: true);
+      gitDiffResponse = 'packages/plugin/pubspec.yaml';
+      gitShowResponses = <String, String>{
+        'abc123:packages/plugin/pubspec.yaml': 'version: 0.6.2',
+        'HEAD:packages/plugin/pubspec.yaml': 'version: 0.6.1',
+      };
+      final List<String> output =
+          await runCapturingPrint(runner, <String>['version-check']);
+
+      expect(
+        output,
+        containsAllInOrder(<String>[
+          '${indentation}New version is lower than previous version. This is assumed to be a revert.',
+        ]),
+      );
+    });
+
+    test('denies lower version that could not be a simple revert', () async {
+      createFakePlugin('plugin', includeChangeLog: true, includeVersion: true);
+      gitDiffResponse = 'packages/plugin/pubspec.yaml';
+      gitShowResponses = <String, String>{
+        'abc123:packages/plugin/pubspec.yaml': 'version: 0.6.2',
+        'HEAD:packages/plugin/pubspec.yaml': 'version: 0.5.1',
+      };
+      final Future<List<String>> result =
+          runCapturingPrint(runner, <String>['version-check']);
+
+      await expectLater(
+        result,
+        throwsA(const TypeMatcher<ToolExit>()),
+      );
+    });
+
     test('denies invalid version without explicit base-sha', () async {
       createFakePlugin('plugin', includeChangeLog: true, includeVersion: true);
       gitDiffResponse = 'packages/plugin/pubspec.yaml';