[flutter_conductor] Push correct revision to mirror remote from conductor (#88607)

dev/conductor/lib/next.dart

@@ -105,8 +105,6 @@ void runNext({
         upstreamRemote: upstream,
         previousCheckoutLocation: state.engine.checkoutPath,
       );
-      final String headRevision = engine.reverseParse('HEAD');
-
       // check if the candidate branch is enabled in .ci.yaml
       if (!engine.ciYaml.enabledBranches.contains(state.engine.candidateBranch)) {
         engine.ciYaml.enableBranch(state.engine.candidateBranch);
@@ -157,7 +155,7 @@ void runNext({
       }
 
       engine.pushRef(
-        fromRef: headRevision,
+        fromRef: 'HEAD',
         // Explicitly create new branch
         toRef: 'refs/heads/${state.engine.workingBranch}',
         remote: state.engine.mirror.name,
@@ -221,7 +219,6 @@ void runNext({
         upstreamRemote: upstream,
         previousCheckoutLocation: state.framework.checkoutPath,
       );
-      final String headRevision = framework.reverseParse('HEAD');
 
       // Check if the current candidate branch is enabled
       if (!framework.ciYaml.enabledBranches.contains(state.framework.candidateBranch)) {
@@ -290,7 +287,7 @@ void runNext({
       }
 
       framework.pushRef(
-        fromRef: headRevision,
+        fromRef: 'HEAD',
         // Explicitly create new branch
         toRef: 'refs/heads/${state.framework.workingBranch}',
         remote: state.framework.mirror.name,

dev/conductor/test/next_test.dart

@@ -84,10 +84,6 @@ void main() {
           const FakeCommand(
             command: <String>['git', 'checkout', workingBranch],
           ),
-          const FakeCommand(
-            command: <String>['git', 'rev-parse', 'HEAD'],
-            stdout: revision1,
-          ),
         ]);
         final FakePlatform platform = FakePlatform(
           environment: <String, String>{
@@ -149,10 +145,6 @@ void main() {
         final FakeProcessManager processManager = FakeProcessManager.list(<FakeCommand>[
           const FakeCommand(command: <String>['git', 'fetch', 'upstream']),
           const FakeCommand(command: <String>['git', 'checkout', workingBranch]),
-          const FakeCommand(
-            command: <String>['git', 'rev-parse', 'HEAD'],
-            stdout: revision1,
-          ),
           const FakeCommand(
             command: <String>['git', 'status', '--porcelain'],
             stdout: 'MM blah',
@@ -233,10 +225,6 @@ void main() {
               _initializeCiYamlFile(file);
             },
           ),
-          const FakeCommand(
-            command: <String>['git', 'rev-parse', 'HEAD'],
-            stdout: revision1,
-          ),
           const FakeCommand(
             command: <String>['git', 'status', '--porcelain'],
             stdout: 'MM .ci.yaml',
@@ -247,7 +235,7 @@ void main() {
             command: <String>['git', 'rev-parse', 'HEAD'],
             stdout: revision2,
           ),
-          const FakeCommand(command: <String>['git', 'push', 'mirror', '$revision1:refs/heads/$workingBranch']),
+          const FakeCommand(command: <String>['git', 'push', 'mirror', 'HEAD:refs/heads/$workingBranch']),
         ]);
         final FakePlatform platform = FakePlatform(
           environment: <String, String>{
@@ -533,10 +521,6 @@ void main() {
               _initializeCiYamlFile(file);
             },
           ),
-          const FakeCommand(
-            command: <String>['git', 'rev-parse', 'HEAD'],
-            stdout: revision2,
-          ),
           const FakeCommand(
             command: <String>['git', 'status', '--porcelain'],
             stdout: 'MM /path/to/.ci.yaml',
@@ -627,10 +611,6 @@ void main() {
           ),
           const FakeCommand(command: <String>['git', 'fetch', 'upstream']),
           const FakeCommand(command: <String>['git', 'checkout', workingBranch]),
-          const FakeCommand(
-            command: <String>['git', 'rev-parse', 'HEAD'],
-            stdout: revision2,
-          ),
           const FakeCommand(
             command: <String>['git', 'status', '--porcelain'],
             stdout: 'MM path/to/.ci.yaml',
@@ -709,10 +689,6 @@ void main() {
               _initializeCiYamlFile(file);
             },
           ),
-          const FakeCommand(
-            command: <String>['git', 'rev-parse', 'HEAD'],
-            stdout: revision2,
-          ),
           const FakeCommand(
             command: <String>['git', 'status', '--porcelain'],
             stdout: 'MM path/to/.ci.yaml',
@@ -742,7 +718,7 @@ void main() {
             stdout: revision4,
           ),
           const FakeCommand(
-            command: <String>['git', 'push', 'mirror', '$revision2:refs/heads/$workingBranch'],
+            command: <String>['git', 'push', 'mirror', 'HEAD:refs/heads/$workingBranch'],
           ),
         ]);
         writeStateToFile(
@@ -783,7 +759,7 @@ void main() {
         );
         expect(
           stdio.stdout,
-          contains('Executed command: `git push mirror $revision2:refs/heads/$workingBranch`'),
+          contains('Executed command: `git push mirror HEAD:refs/heads/$workingBranch`'),
         );
         expect(stdio.error, isEmpty);
       });