Merge branch 'mh/notes-allow-reading-treeish'

Some "git notes" operations, e.g. "git log --notes=<note>", should
be able to read notes from any tree-ish that is shaped like a notes
tree, but the notes infrastructure required that the argument must
be a ref under refs/notes/.  Loosen it to require a valid ref only
when the operation would update the notes (in which case we must
have a place to store the updated notes tree, iow, a ref).

* mh/notes-allow-reading-treeish:
  notes: allow treeish expressions as notes ref

1 files changed, 7 insertions, 4 deletions

diff --git a/notes.c b/notes.c
index db77922130..358e2fdb74 100644
--- a/notes.c
+++ b/notes.c
@@ -1011,13 +1011,16 @@ void init_notes(struct notes_tree *t, const char *notes_ref,
 	t->first_non_note = NULL;
 	t->prev_non_note = NULL;
 	t->ref = xstrdup_or_null(notes_ref);
+	t->update_ref = (flags & NOTES_INIT_WRITABLE) ? t->ref : NULL;
 	t->combine_notes = combine_notes;
 	t->initialized = 1;
 	t->dirty = 0;
 
 	if (flags & NOTES_INIT_EMPTY || !notes_ref ||
-	    read_ref(notes_ref, object_sha1))
+	    get_sha1_treeish(notes_ref, object_sha1))
 		return;
+	if (flags & NOTES_INIT_WRITABLE && read_ref(notes_ref, object_sha1))
+		die("Cannot use notes ref %s", notes_ref);
 	if (get_tree_entry(object_sha1, "", sha1, &mode))
 		die("Failed to read notes tree referenced by %s (%s)",
 		    notes_ref, sha1_to_hex(object_sha1));
@@ -1027,7 +1030,7 @@ void init_notes(struct notes_tree *t, const char *notes_ref,
 	load_subtree(t, &root_tree, t->root, 0);
 }
 
-struct notes_tree **load_notes_trees(struct string_list *refs)
+struct notes_tree **load_notes_trees(struct string_list *refs, int flags)
 {
 	struct string_list_item *item;
 	int counter = 0;
@@ -1035,7 +1038,7 @@ struct notes_tree **load_notes_trees(struct string_list *refs)
 	trees = xmalloc((refs->nr+1) * sizeof(struct notes_tree *));
 	for_each_string_list_item(item, refs) {
 		struct notes_tree *t = xcalloc(1, sizeof(struct notes_tree));
-		init_notes(t, item->string, combine_notes_ignore, 0);
+		init_notes(t, item->string, combine_notes_ignore, flags);
 		trees[counter++] = t;
 	}
 	trees[counter] = NULL;
@@ -1071,7 +1074,7 @@ void init_display_notes(struct display_notes_opt *opt)
 						     item->string);
 	}
 
-	display_notes_trees = load_notes_trees(&display_notes_refs);
+	display_notes_trees = load_notes_trees(&display_notes_refs, 0);
 	string_list_clear(&display_notes_refs, 0);
 }