Add Task to Verify Branch Version Matches the Project Version

Closes gh-15226

build.gradle

@@ -25,6 +25,7 @@ apply plugin: 'org.springframework.github.milestone'
 apply plugin: 'org.springframework.github.changelog'
 apply plugin: 'org.springframework.github.release'
 apply plugin: 'org.springframework.security.versions.verify-dependencies-versions'
+apply plugin: 'org.springframework.security.check-expected-branch-version'
 
 group = 'org.springframework.security'
 description = 'Spring Security'

buildSrc/build.gradle

@@ -68,6 +68,10 @@ gradlePlugin {
 			id = "org.springframework.security.versions.verify-dependencies-versions"
 			implementationClass = "org.springframework.security.convention.versions.VerifyDependenciesVersionsPlugin"
 		}
+		checkExpectedBranchVersion {
+			id = "org.springframework.security.check-expected-branch-version"
+			implementationClass = "org.springframework.security.CheckExpectedBranchVersionPlugin"
+		}
 	}
 }
 

buildSrc/src/main/java/org/springframework/security/CheckExpectedBranchVersionPlugin.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * 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
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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 org.springframework.security;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+
+import org.gradle.api.DefaultTask;
+import org.gradle.api.Plugin;
+import org.gradle.api.Project;
+import org.gradle.api.plugins.JavaBasePlugin;
+import org.gradle.api.tasks.TaskAction;
+import org.gradle.api.tasks.TaskProvider;
+
+/**
+ * @author Marcus da Coregio
+ */
+public class CheckExpectedBranchVersionPlugin implements Plugin<Project> {
+
+	@Override
+	public void apply(Project project) {
+		TaskProvider<CheckExpectedBranchVersionTask> checkExpectedBranchVersionTask = project.getTasks().register("checkExpectedBranchVersion", CheckExpectedBranchVersionTask.class, (task) -> {
+			task.setGroup("Build");
+			task.setDescription("Check if the project version matches the branch version");
+		});
+		project.getTasks().named(JavaBasePlugin.CHECK_TASK_NAME, checkTask -> checkTask.dependsOn(checkExpectedBranchVersionTask));
+	}
+
+	public static class CheckExpectedBranchVersionTask extends DefaultTask {
+
+		@TaskAction
+		public void run() throws IOException {
+			Project project = getProject();
+			String version = (String) project.getVersion();
+			String branchVersion = getBranchVersion(project);
+			if (!branchVersion.matches("^[0-9]+\\.[0-9]+\\.x$")) {
+				System.out.println("Branch version does not match *.x, ignoring");
+				return;
+			}
+			if (!versionsMatch(version, branchVersion)) {
+				throw new IllegalStateException(String.format("Project version [%s] does not match branch version [%s]. " +
+						"Please verify that the branch contains the right version.", version, branchVersion));
+			}
+		}
+
+		private static String getBranchVersion(Project project) throws IOException {
+			try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
+				project.exec((exec) -> {
+					exec.commandLine("git", "symbolic-ref", "--short", "HEAD");
+					exec.setErrorOutput(System.err);
+					exec.setStandardOutput(baos);
+				});
+				return baos.toString();
+			}
+		}
+
+		private boolean versionsMatch(String projectVersion, String branchVersion) {
+			String[] projectVersionParts = projectVersion.split("\\.");
+			String[] branchVersionParts = branchVersion.split("\\.");
+			if (projectVersionParts.length < 2 || branchVersionParts.length < 2) {
+				return false;
+			}
+			return projectVersionParts[0].equals(branchVersionParts[0]) && projectVersionParts[1].equals(branchVersionParts[1]);
+		}
+
+	}
+
+}