[PATCH] push: cleanup push rules comment

[Chris Rorvick <chris@rorvick.com>]

---

I ended up rewriting most of the comment.  The new version removes
inter-rule dependencies (e.g., rule 5 overrides rule 3) which I think
makes it more readable.

This patch applies on top of the latest patch series regarding
pushing tags.  If will include this in a re-roll of that series if
these changes are deemed a good idea.

Also, I hand-edited the patch so that the changes were not interleaved
to make it much easier to read.  Can this be done automatically?
Something like a minimum # of matching lines required between
differences?

Chris

 remote.c | 32 +++++++++++++++++---------------
 1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/remote.c b/remote.c
index ee0c1e5..3fb1068 100644
--- a/remote.c
+++ b/remote.c
@@ -1319,27 +1319,29 @@ void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
 			continue;
 		}
 
-		/* This part determines what can overwrite what.
-		 * The rules are:
-		 *
-		 * (0) you can always use --force or +A:B notation to
-		 *     selectively force individual ref pairs.
-		 *
-		 * (1) if the old thing does not exist, it is OK.
-		 *
-		 * (2) if the destination is under refs/tags/ you are
-		 *     not allowed to overwrite it; tags are expected
-		 *     to be static once created
-		 *
-		 * (3) if you do not have the old thing, you are not allowed
-		 *     to overwrite it; you would not know what you are losing
-		 *     otherwise.
-		 *
-		 * (4) if old is a commit and new is a descendant of old
-		 *     (implying new is commit-ish), it is OK.
-		 *
-		 * (5) regardless of all of the above, removing :B is
-		 *     always allowed.
+		/*
+		 * The below logic determines whether an individual
+		 * refspec A:B can be pushed.  The push will succeed
+		 * if any of the following are true:
+		 *
+		 * (1) the remote reference B does not exist
+		 *
+		 * (2) the remote reference B is being removed (i.e.
+		 *     pushing :B where no source is specified)
+		 *
+		 * (3) the update meets all fast-forwarding criteria:
+		 *
+		 *     (a) the destination is not under refs/tags/
+		 *     (b) the old is a commit
+		 *     (c) the new is a descendant of the old
+		 *
+		 *     NOTE: We must actually have the old object in
+		 *     order to overwrite it in the remote reference,
+		 *     and that the new object must be commit-ish.
+		 *     These are implied by (b) and (c) respectively.
+		 *
+		 * (4) it is forced using the +A:B notation, or by
+		 *     passing the --force argument
 		 */
 
 		ref->not_forwardable = !is_forwardable(ref);
-- 
1.8.0.209.gf3828dc