Re: [JGIT PATCH 1/4] Ensured that RefUpdate cannot delete current branch

["Shawn O. Pearce" <spearce@spearce.org>]

Charles O'Farrell <charleso@charleso.org> wrote:
> If attempted it will return a REJECTED_CURRENT_BRANCH Result.
 
> @@ -323,6 +330,9 @@ public Result update(final RevWalk walk) throws IOException {
>  	 * @throws IOException
>  	 */
>  	public Result delete() throws IOException {
> +		if (name.substring(Constants.R_HEADS.length()).equals(
> +				db.getRepository().getBranch()))
> +			return Result.REJECTED_CURRENT_BRANCH;
>  		try {
>  			return updateImpl(new RevWalk(db.getRepository()),
>  					new DeleteStore());

I'm squashing this into the patch, as I think its a safer (and
faster) way to evaluate what the current branch is.  We have a
cache in RefDatabase showing the current value of HEAD.  We also
don't look at .git/head-name, which happens during a bisection.

But I also don't think we want to mess around with this test if
we are dealing with refs/remotes or refs/tags.  Really it is only
refs/heads/ that should typically appear in HEAD, so we only need
to guard against that case.  If the user knows enough to make HEAD
point at something else, maybe they will also know enough to not
delete the damn thing out from under themselves.  If we did fix it
to test for all refs, its just a matter of removing the first if.

diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/RefUpdate.java b/org.spearce.jgit/src/org/spearce/jgit/lib/RefUpdate.java
index aa2cecb..77dada0 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/lib/RefUpdate.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/lib/RefUpdate.java
@@ -330,9 +330,12 @@ public Result update(final RevWalk walk) throws IOException {
 	 * @throws IOException
 	 */
 	public Result delete() throws IOException {
-		if (name.substring(Constants.R_HEADS.length()).equals(
-				db.getRepository().getBranch()))
-			return Result.REJECTED_CURRENT_BRANCH;
+		if (name.startsWith(Constants.R_HEADS)) {
+			final Ref head = db.readRef(Constants.HEAD);
+			if (head != null && name.equals(head.getName()))
+				return Result.REJECTED_CURRENT_BRANCH;
+		}
+
 		try {
 			return updateImpl(new RevWalk(db.getRepository()),
 					new DeleteStore());

-- 
Shawn.