Ignore empty lines when parsing git-rebase-todo

When starting a rebase with C Git, there may be empty lines in the
git-rebase-todo file. Before this change, JGit would fail to parse the
file with e.g. the following exception:

  JGitInternalException: Unknown or unsupported command "
  #", only "pick" is allowed.

This happened when there was an empty line just before the comments,
because the nextSpace would be the one from the comment. Now the empty
lines are ignored by checking for nextSpace < ptr outside of the loop.

Change-Id: I94ad299f367c846e7729c74f49c6b8f93f75ae81
Signed-off-by: Robin Stocker <robin@nibor.org>

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

@@ -53,10 +53,12 @@ import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.util.List;
 
 import org.eclipse.jgit.api.MergeResult.MergeStatus;
 import org.eclipse.jgit.api.RebaseCommand.Action;
 import org.eclipse.jgit.api.RebaseCommand.Operation;
+import org.eclipse.jgit.api.RebaseCommand.Step;
 import org.eclipse.jgit.api.RebaseResult.Status;
 import org.eclipse.jgit.api.errors.JGitInternalException;
 import org.eclipse.jgit.api.errors.RefNotFoundException;
@@ -1365,8 +1367,7 @@ public class RebaseCommandTest extends RepositoryTestCase {
 
 	private int countPicks() throws IOException {
 		int count = 0;
-		File todoFile = new File(db.getDirectory(),
-				"rebase-merge/git-rebase-todo");
+		File todoFile = getTodoFile();
 		BufferedReader br = new BufferedReader(new InputStreamReader(
 				new FileInputStream(todoFile), "UTF-8"));
 		try {
@@ -1470,4 +1471,26 @@ public class RebaseCommandTest extends RepositoryTestCase {
 		assertEquals(RepositoryState.SAFE, git.getRepository()
 				.getRepositoryState());
 	}
+
+	@Test
+	public void testRebaseShouldBeAbleToHandleEmptyLinesInRebaseTodoFile()
+			throws IOException {
+		String emptyLine = "\n";
+		String todo = "pick 1111111 Commit 1\n" + emptyLine
+				+ "pick 2222222 Commit 2\n" + emptyLine
+				+ "# Comment line at end\n";
+		write(getTodoFile(), todo);
+
+		RebaseCommand rebaseCommand = git.rebase();
+		List<Step> steps = rebaseCommand.loadSteps();
+		assertEquals(2, steps.size());
+		assertEquals("1111111", steps.get(0).commit.name());
+		assertEquals("2222222", steps.get(1).commit.name());
+	}
+
+	private File getTodoFile() {
+		File todoFile = new File(db.getDirectory(),
+				"rebase-merge/git-rebase-todo");
+		return todoFile;
+	}
 }

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

@@ -824,7 +824,7 @@ public class RebaseCommand extends GitCommand<RebaseResult> {
 		return true;
 	}
 
-	private List<Step> loadSteps() throws IOException {
+	List<Step> loadSteps() throws IOException {
 		byte[] buf = IO.readFully(new File(rebaseDir, GIT_REBASE_TODO));
 		int ptr = 0;
 		int tokenBegin = 0;
@@ -832,13 +832,12 @@ public class RebaseCommand extends GitCommand<RebaseResult> {
 		while (ptr < buf.length) {
 			tokenBegin = ptr;
 			ptr = RawParseUtils.nextLF(buf, ptr);
-			int nextSpace = 0;
+			int nextSpace = RawParseUtils.next(buf, tokenBegin, ' ');
 			int tokenCount = 0;
 			Step current = null;
 			while (tokenCount < 3 && nextSpace < ptr) {
 				switch (tokenCount) {
 				case 0:
-					nextSpace = RawParseUtils.next(buf, tokenBegin, ' ');
 					String actionToken = new String(buf, tokenBegin, nextSpace
 							- tokenBegin - 1);
 					tokenBegin = nextSpace;