From 5f037762c7d1bff1f4e604ef11a20404b420f2e6 Mon Sep 17 00:00:00 2001
From: Rene Pfeuffer <rene.pfeuffer@cloudogu.com>
Date: Wed, 4 Sep 2019 13:24:59 +0200
Subject: [PATCH] Verify that branch is a branch

---
 .../scm/repository/spi/GitModifyCommand.java     |  7 +++++++
 .../scm/repository/spi/GitModifyCommandTest.java | 16 ++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitModifyCommand.java b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitModifyCommand.java
index 4ff60445f7..9aa3eebe27 100644
--- a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitModifyCommand.java
+++ b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitModifyCommand.java
@@ -3,10 +3,13 @@ package sonia.scm.repository.spi;
 import org.apache.commons.lang.StringUtils;
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.api.errors.GitAPIException;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.revwalk.RevCommit;
 import sonia.scm.BadRequestException;
 import sonia.scm.ConcurrentModificationException;
 import sonia.scm.ContextEntry;
+import sonia.scm.ScmConstraintViolationException;
 import sonia.scm.repository.GitWorkdirFactory;
 import sonia.scm.repository.InternalRepositoryException;
 import sonia.scm.repository.Repository;
@@ -21,6 +24,7 @@ import java.util.Optional;
 import static java.nio.file.StandardCopyOption.REPLACE_EXISTING;
 import static sonia.scm.AlreadyExistsException.alreadyExists;
 import static sonia.scm.ContextEntry.ContextBuilder.entity;
+import static sonia.scm.ScmConstraintViolationException.Builder.doThrow;
 
 public class GitModifyCommand extends AbstractGitCommand implements ModifyCommand {
 
@@ -52,6 +56,9 @@ public class GitModifyCommand extends AbstractGitCommand implements ModifyComman
       if (!StringUtils.isEmpty(request.getBranch())) {
         checkOutBranch(request.getBranch());
       }
+      Ref head = getClone().getRepository().exactRef(Constants.HEAD);
+      doThrow().violation("branch has to be a valid branch, no revision", "branch", request.getBranch()).when(head == null || !head.isSymbolic());
+      getClone().getRepository().getFullBranch();
       if (!StringUtils.isEmpty(request.getExpectedRevision())) {
         if (!request.getExpectedRevision().equals(getCurrentRevision().getName())) {
           throw new ConcurrentModificationException("branch", request.getBranch() == null? "default": request.getBranch());
diff --git a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitModifyCommandTest.java b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitModifyCommandTest.java
index 96cc256cf4..8d9cc5bc5a 100644
--- a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitModifyCommandTest.java
+++ b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitModifyCommandTest.java
@@ -16,6 +16,7 @@ import org.junit.rules.TemporaryFolder;
 import sonia.scm.AlreadyExistsException;
 import sonia.scm.BadRequestException;
 import sonia.scm.ConcurrentModificationException;
+import sonia.scm.ScmConstraintViolationException;
 import sonia.scm.repository.Person;
 import sonia.scm.repository.util.WorkdirProvider;
 
@@ -156,6 +157,21 @@ public class GitModifyCommandTest extends AbstractGitCommandTestBase {
     command.execute(request);
   }
 
+  @Test(expected = ScmConstraintViolationException.class)
+  public void shouldFailWithConstraintViolationIfBranchIsNoBranch() throws IOException {
+    File newFile = Files.write(temporaryFolder.newFile().toPath(), "irrelevant\n".getBytes()).toFile();
+
+    GitModifyCommand command = createCommand();
+
+    ModifyCommandRequest request = new ModifyCommandRequest();
+    request.setCommitMessage("test commit");
+    request.setBranch("3f76a12f08a6ba0dc988c68b7f0b2cd190efc3c4");
+    request.addRequest(new ModifyCommandRequest.CreateFileRequest("irrelevant", newFile, true));
+    request.setAuthor(new Person("Dirk Gently", "dirk@holistic.det"));
+
+    command.execute(request);
+  }
+
   private void assertInTree(TreeAssertions assertions) throws IOException, GitAPIException {
     try (Git git = new Git(createContext().open())) {
       RevCommit lastCommit = getLastCommit(git);