Undo the repo tooling part of the revert

script/tool/CHANGELOG.md

@@ -1,3 +1,7 @@
+## NEXT
+
+- Fixes changelog validation when reverting to a `NEXT` state.
+
 ## 0.8.5
 
 - Updates `test` to inculde the Dart unit tests of examples, if any.
@@ -322,7 +326,7 @@ and `firebase-test-lab`.
 
 ## v.0.0.36+2
 
-- Default to showing podspec lint warnings.
+- Default to showing podspec lint warnings
 
 ## v.0.0.36+1
 

script/tool/lib/src/version_check_command.dart

@@ -39,8 +39,11 @@ enum _CurrentVersionState {
   /// The version is unchanged.
   unchanged,
 
-  /// The version has changed, and the transition is valid.
-  validChange,
+  /// The version has increased, and the transition is valid.
+  validIncrease,
+
+  /// The version has decrease, and the transition is a valid revert.
+  validRevert,
 
   /// The version has changed, and the transition is invalid.
   invalidChange,
@@ -218,7 +221,8 @@ class VersionCheckCommand extends PackageLoopingCommand {
       case _CurrentVersionState.unchanged:
         versionChanged = false;
         break;
-      case _CurrentVersionState.validChange:
+      case _CurrentVersionState.validIncrease:
+      case _CurrentVersionState.validRevert:
         versionChanged = true;
         break;
       case _CurrentVersionState.invalidChange:
@@ -232,7 +236,7 @@ class VersionCheckCommand extends PackageLoopingCommand {
     }
 
     if (!(await _validateChangelogVersion(package,
-        pubspec: pubspec, pubspecVersionChanged: versionChanged))) {
+        pubspec: pubspec, pubspecVersionState: versionState))) {
       errors.add('CHANGELOG.md failed validation.');
     }
 
@@ -322,7 +326,7 @@ ${indentation}HTTP response: ${pubVersionFinderResponse.httpResponse.body}
           '${getBoolArg(_againstPubFlag) ? 'on pub server' : 'at git base'}.');
       logWarning(
           '${indentation}If this plugin is not new, something has gone wrong.');
-      return _CurrentVersionState.validChange; // Assume new, thus valid.
+      return _CurrentVersionState.validIncrease; // Assume new, thus valid.
     }
 
     if (previousVersion == currentVersion) {
@@ -340,7 +344,7 @@ ${indentation}HTTP response: ${pubVersionFinderResponse.httpResponse.body}
       if (possibleVersionsFromNewVersion.containsKey(previousVersion)) {
         logWarning('${indentation}New version is lower than previous version. '
             'This is assumed to be a revert.');
-        return _CurrentVersionState.validChange;
+        return _CurrentVersionState.validRevert;
       }
     }
 
@@ -367,7 +371,7 @@ ${indentation}HTTP response: ${pubVersionFinderResponse.httpResponse.body}
       return _CurrentVersionState.invalidChange;
     }
 
-    return _CurrentVersionState.validChange;
+    return _CurrentVersionState.validIncrease;
   }
 
   /// Checks whether or not [package]'s CHANGELOG's versioning is correct,
@@ -378,7 +382,7 @@ ${indentation}HTTP response: ${pubVersionFinderResponse.httpResponse.body}
   Future<bool> _validateChangelogVersion(
     RepositoryPackage package, {
     required Pubspec pubspec,
-    required bool pubspecVersionChanged,
+    required _CurrentVersionState pubspecVersionState,
   }) async {
     // This method isn't called unless `version` is non-null.
     final Version fromPubspec = pubspec.version!;
@@ -405,8 +409,9 @@ ${indentation}HTTP response: ${pubVersionFinderResponse.httpResponse.body}
     // changes that don't warrant publishing on their own.
     final bool hasNextSection = versionString == 'NEXT';
     if (hasNextSection) {
-      // NEXT should not be present in a commit that changes the version.
-      if (pubspecVersionChanged) {
+      // NEXT should not be present in a commit that increases the version.
+      if (pubspecVersionState == _CurrentVersionState.validIncrease ||
+          pubspecVersionState == _CurrentVersionState.invalidChange) {
         printError(badNextErrorMessage);
         return false;
       }

script/tool/test/version_check_command_test.dart

@@ -44,7 +44,7 @@ class MockProcessResult extends Mock implements io.ProcessResult {}
 
 void main() {
   const String indentation = '  ';
-  group('$VersionCheckCommand', () {
+  group('VersionCheckCommand', () {
     late FileSystem fileSystem;
     late MockPlatform mockPlatform;
     late Directory packagesDir;
@@ -602,7 +602,7 @@ This is necessary because of X, Y, and Z
       );
     });
 
-    test('Fail if the version changes without replacing NEXT', () async {
+    test('fails if the version increases without replacing NEXT', () async {
       final RepositoryPackage plugin =
           createFakePlugin('plugin', packagesDir, version: '1.0.1');
 
@@ -632,6 +632,33 @@ This is necessary because of X, Y, and Z
       );
     });
 
+    test('allows NEXT for a revert', () async {
+      final RepositoryPackage plugin =
+          createFakePlugin('plugin', packagesDir, version: '1.0.0');
+
+      const String changelog = '''
+## NEXT
+* Some changes that should be listed as part of 1.0.1.
+## 1.0.0
+* Some other changes.
+''';
+      createFakeCHANGELOG(plugin, changelog);
+      createFakeCHANGELOG(plugin, changelog);
+      processRunner.mockProcessesForExecutable['git-show'] = <io.Process>[
+        MockProcess(stdout: 'version: 1.0.1'),
+      ];
+
+      final List<String> output = await runCapturingPrint(
+          runner, <String>['version-check', '--base-sha=main']);
+      expect(
+        output,
+        containsAllInOrder(<Matcher>[
+          contains('New version is lower than previous version. '
+              'This is assumed to be a revert.'),
+        ]),
+      );
+    });
+
     test(
         'fails gracefully if the version headers are not found due to using the wrong style',
         () async {