[findBugs] Don't pass null for non-null parameter in RebaseCommand

Change-Id: Iee4d50aa9c6b75f9906d2c51a940ddc90a944192

org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties

@@ -1,6 +1,7 @@
 abbreviationLengthMustBeNonNegative=Abbreviation length must not be negative.
 abortingRebase=Aborting rebase: resetting to {0}
 abortingRebaseFailed=Could not abort rebase
+abortingRebaseFailedNoOrigHead=Could not abort rebase since ORIG_HEAD is null
 advertisementCameBefore=advertisement of {0}^{} came before {1}
 advertisementOfCameBefore=advertisement of {0}^{} came before {1}
 amazonS3ActionFailed={0} of ''{1}'' failed: {2} {3}

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

@@ -822,7 +822,11 @@ public class RebaseCommand extends GitCommand<RebaseResult> {
 					ProgressMonitor.UNKNOWN);
 
 			DirCacheCheckout dco;
-			RevCommit commit = walk.parseCommit(repo.resolve(commitId));
+			if (commitId == null)
+				throw new JGitInternalException(
+						JGitText.get().abortingRebaseFailedNoOrigHead);
+			ObjectId id = repo.resolve(commitId);
+			RevCommit commit = walk.parseCommit(id);
 			if (result.getStatus().equals(Status.FAILED)) {
 				RevCommit head = walk.parseCommit(repo.resolve(Constants.HEAD));
 				dco = new DirCacheCheckout(repo, head.getTree(),

org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java

@@ -62,6 +62,7 @@ public class JGitText extends TranslationBundle {
 	/***/ public String abbreviationLengthMustBeNonNegative;
 	/***/ public String abortingRebase;
 	/***/ public String abortingRebaseFailed;
+	/***/ public String abortingRebaseFailedNoOrigHead;
 	/***/ public String advertisementCameBefore;
 	/***/ public String advertisementOfCameBefore;
 	/***/ public String amazonS3ActionFailed;