StashCreateCommand: Abort in case of unmerged paths

Bug: 391861
Change-Id: I5f8ffe072c08c8ca2ca6be6b6afa67c8e16a63b6

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/StashCreateCommandTest.java

@@ -52,6 +52,7 @@ import java.io.File;
 import java.io.IOException;
 import java.util.List;
 
+import org.eclipse.jgit.api.errors.UnmergedPathsException;
 import org.eclipse.jgit.diff.DiffEntry;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.ObjectId;
@@ -417,4 +418,14 @@ public class StashCreateCommandTest extends RepositoryTestCase {
 		assertEquals(who, entry.getWho());
 		assertEquals(stashed.getFullMessage(), entry.getComment());
 	}
+
+	@Test(expected = UnmergedPathsException.class)
+	public void unmergedPathsShouldCauseException() throws Exception {
+		commitFile("file.txt", "master", "base");
+		RevCommit side = commitFile("file.txt", "side", "side");
+		commitFile("file.txt", "master", "master");
+		git.merge().include(side).call();
+
+		git.stashCreate().call();
+	}
 }

org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RepositoryTestCase.java

@@ -58,6 +58,8 @@ import java.io.Reader;
 import java.util.Map;
 import java.util.TreeSet;
 
+import org.eclipse.jgit.api.Git;
+import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.dircache.DirCache;
 import org.eclipse.jgit.dircache.DirCacheBuilder;
 import org.eclipse.jgit.dircache.DirCacheCheckout;
@@ -436,4 +438,37 @@ public abstract class RepositoryTestCase extends LocalDiskRepositoryTestCase {
 					}
 				return f;
 			}
+
+	/**
+	 * Commit a file with the specified contents on the specified branch,
+	 * creating the branch if it didn't exist before.
+	 * <p>
+	 * It switches back to the original branch after the commit if there was
+	 * one.
+	 *
+	 * @param filename
+	 * @param contents
+	 * @param branch
+	 * @return the created commit
+	 */
+	protected RevCommit commitFile(String filename, String contents, String branch) {
+		try {
+			Git git = new Git(db);
+			String originalBranch = git.getRepository().getFullBranch();
+			if (git.getRepository().getRef(branch) == null)
+				git.branchCreate().setName(branch).call();
+			git.checkout().setName(branch).call();
+			writeTrashFile(filename, contents);
+			git.add().addFilepattern(filename).call();
+			RevCommit commit = git.commit()
+					.setMessage(branch + ": " + filename).call();
+			if (originalBranch != null)
+				git.checkout().setName(originalBranch).call();
+			return commit;
+		} catch (IOException e) {
+			throw new RuntimeException(e);
+		} catch (GitAPIException e) {
+			throw new RuntimeException(e);
+		}
+	}
 }

org.eclipse.jgit/src/org/eclipse/jgit/api/StashCreateCommand.java

@@ -52,12 +52,14 @@ import org.eclipse.jgit.api.ResetCommand.ResetType;
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.api.errors.JGitInternalException;
 import org.eclipse.jgit.api.errors.NoHeadException;
+import org.eclipse.jgit.api.errors.UnmergedPathsException;
 import org.eclipse.jgit.dircache.DirCache;
 import org.eclipse.jgit.dircache.DirCacheEditor;
 import org.eclipse.jgit.dircache.DirCacheEditor.DeletePath;
 import org.eclipse.jgit.dircache.DirCacheEditor.PathEdit;
 import org.eclipse.jgit.dircache.DirCacheEntry;
 import org.eclipse.jgit.dircache.DirCacheIterator;
+import org.eclipse.jgit.errors.UnmergedPathException;
 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.lib.CommitBuilder;
 import org.eclipse.jgit.lib.Constants;
@@ -247,6 +249,10 @@ public class StashCreateCommand extends GitCommand<RevCommit> {
 					WorkingTreeIterator wtIter = treeWalk.getTree(2,
 							WorkingTreeIterator.class);
 					if (headIter != null && indexIter != null && wtIter != null) {
+						if (!indexIter.getDirCacheEntry().isMerged())
+							throw new UnmergedPathsException(
+									new UnmergedPathException(
+											indexIter.getDirCacheEntry()));
 						if (wtIter.idEqual(indexIter)
 								|| wtIter.idEqual(headIter))
 							continue;

org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheEntry.java

@@ -446,6 +446,15 @@ public class DirCacheEntry {
 		return (getExtendedFlags() & INTENT_TO_ADD) != 0;
 	}
 
+	/**
+	 * Returns whether this entry is in the fully-merged stage (0).
+	 *
+	 * @return true if this entry is merged
+	 */
+	public boolean isMerged() {
+		return getStage() == STAGE_0;
+	}
+
 	/**
 	 * Obtain the raw {@link FileMode} bits for this entry.
 	 *