Checking out branches before doing release tasks

Author: marcingrzejszczak

src/main/java/io/micrometer/release/train/Git.java

@@ -0,0 +1,36 @@
+/**
+ * Copyright 2025 the original author or authors.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package io.micrometer.release.train;
+
+import io.micrometer.release.common.ProcessRunner;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+class Git {
+
+    private static final Logger log = LoggerFactory.getLogger(Git.class);
+
+    private final ProcessRunner processRunner;
+
+    Git(ProcessRunner processRunner) {
+        this.processRunner = processRunner;
+    }
+
+    void changeTag(String tag) {
+        log.info("Changing git head to tag [{}]", tag);
+        processRunner.run("git", "fetch", "origin", "refs/tags/" + tag);
+        processRunner.run("git", "checkout", tag);
+    }
+
+}

src/main/java/io/micrometer/release/train/PostReleaseTaskScheduler.java

@@ -30,10 +30,13 @@ class PostReleaseTaskScheduler {
 
     private final PostReleaseWorkflow postReleaseWorkflow;
 
+    private final Git git;
+
     private final String githubOrgRepo;
 
-    PostReleaseTaskScheduler(PostReleaseWorkflow postReleaseWorkflow, String githubOrgRepo) {
+    PostReleaseTaskScheduler(PostReleaseWorkflow postReleaseWorkflow, Git git, String githubOrgRepo) {
         this.postReleaseWorkflow = postReleaseWorkflow;
+        this.git = git;
         this.githubOrgRepo = githubOrgRepo;
     }
 
@@ -42,6 +45,7 @@ void runPostReleaseTasks(List<String> versions) {
         sortedVersions.sort(Comparator.comparing(PostReleaseTaskScheduler::extractMajorMinorVersion));
         String previousVersion = null;
         for (String version : sortedVersions) {
+            git.changeTag("v" + version);
             log.info("Running post release task for version [{}] and previous version [{}]", version, previousVersion);
             postReleaseWorkflow.run(githubOrgRepo, "v" + version,
                     previousVersion != null ? ("v" + previousVersion) : null);

src/main/java/io/micrometer/release/train/ProjectTrainReleaseWorkflow.java

@@ -47,7 +47,8 @@ public ProjectTrainReleaseWorkflow(String githubOrgRepo, String artifactToCheck,
                 processRunner);
         this.versionToBranchConverter = new VersionToBranchConverter(System.getenv("GH_TOKEN"),
                 "https://api.github.com/repos/" + githubOrgRepo + "/branches/", HTTP_CLIENT);
-        this.postReleaseTaskScheduler = new PostReleaseTaskScheduler(postReleaseWorkflow, githubOrgRepo);
+        this.postReleaseTaskScheduler = new PostReleaseTaskScheduler(postReleaseWorkflow, new Git(processRunner),
+                githubOrgRepo);
         this.mavenCentralSyncChecker = new MavenCentralSyncChecker(artifactToCheck);
     }
 

src/test/java/io/micrometer/release/train/GitTests.java

@@ -0,0 +1,36 @@
+/**
+ * Copyright 2025 the original author or authors.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package io.micrometer.release.train;
+
+import io.micrometer.release.common.ProcessRunner;
+import org.junit.jupiter.api.Test;
+
+import static org.mockito.BDDMockito.then;
+import static org.mockito.Mockito.mock;
+
+class GitTests {
+
+    ProcessRunner processRunner = mock();
+
+    @Test
+    void should_checkout_tag() {
+        Git git = new Git(processRunner);
+
+        git.changeTag("v1.2.3");
+
+        then(processRunner).should().run("git", "fetch", "origin", "refs/tags/v1.2.3");
+        then(processRunner).should().run("git", "checkout", "v1.2.3");
+    }
+
+}

src/test/java/io/micrometer/release/train/PostReleaseTaskSchedulerTests.java

@@ -28,16 +28,21 @@ class PostReleaseTaskSchedulerTests {
 
     PostReleaseWorkflow postReleaseWorkflow = mock();
 
-    PostReleaseTaskScheduler scheduler = new PostReleaseTaskScheduler(postReleaseWorkflow,
+    Git git = mock();
+
+    PostReleaseTaskScheduler scheduler = new PostReleaseTaskScheduler(postReleaseWorkflow, git,
             "micrometer-metrics/micrometer");
 
     @Test
     void should_schedule_release_tasks() {
         scheduler.runPostReleaseTasks(List.of("1.0.0", "1.1.0", "1.2.0"));
 
-        InOrder inOrder = inOrder(postReleaseWorkflow);
+        InOrder inOrder = inOrder(git, postReleaseWorkflow);
+        inOrder.verify(git).changeTag("v1.0.0");
         inOrder.verify(postReleaseWorkflow).run("micrometer-metrics/micrometer", "v1.0.0", null);
+        inOrder.verify(git).changeTag("v1.1.0");
         inOrder.verify(postReleaseWorkflow).run("micrometer-metrics/micrometer", "v1.1.0", "v1.0.0");
+        inOrder.verify(git).changeTag("v1.2.0");
         inOrder.verify(postReleaseWorkflow).run("micrometer-metrics/micrometer", "v1.2.0", "v1.1.0");
     }
 

src/test/java/io/micrometer/release/train/ProjectTrainReleaseWorkflowAcceptanceTests.java

@@ -55,7 +55,7 @@ class ProjectTrainReleaseWorkflowAcceptanceTests {
     ReleaseScheduler releaseScheduler = new ReleaseScheduler(circleCiChecker, processRunner);
 
     PostReleaseTaskScheduler postReleaseTaskScheduler = new PostReleaseTaskScheduler(postReleaseWorkflow,
-            GITHUB_ORG_REPO);
+            new Git(processRunner), GITHUB_ORG_REPO);
 
     VersionToBranchConverter versionToBranchConverter = new VersionToBranchConverter("foo",
             wm1.url("/repos/micrometer-metrics/micrometer/branches/"), HttpClient.newBuilder().build());