[PATCH 3/4] glossary: more precise definition of tree-ish (a.k.a. treeish)

[Richard Hansen <rhansen@bbn.com>]

Mention dereferencing, and that a commit dereferences to a tree, to
support gitrevisions(7) and rev-parse's error messages.

Signed-off-by: Richard Hansen <rhansen@bbn.com>
---
 Documentation/glossary-content.txt | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/Documentation/glossary-content.txt b/Documentation/glossary-content.txt
index a3cc003..9a50fe1 100644
--- a/Documentation/glossary-content.txt
+++ b/Documentation/glossary-content.txt
@@ -498,9 +498,19 @@ should not be combined with other pathspec.
 	<<def_tree,tree>> is equivalent to a <<def_directory,directory>>.
 
 [[def_tree-ish]]tree-ish (also treeish)::
-	A <<def_ref,ref>> pointing to either a <<def_commit_object,commit
-	object>>, a <<def_tree_object,tree object>>, or a <<def_tag_object,tag
-	object>> pointing to a tag or commit or tree object.
+	A <<def_ref,ref>> pointing to an <<def_object,object>> that
+	can be recursively dereferenced to a
+	<<def_tree_object,tree object>>.
+	Dereferencing a <<def_commit_object,commit object>> yields the
+	tree object corresponding to the <<def_revision,revision>>'s
+	top <<def_directory,directory>>.
+	The following are all tree-ishes:
+	a <<def_committish,committish>>,
+	a ref pointing to a tree object,
+	a ref pointing to a <<def_tag_object,tag object>> that points
+	to a tree object,
+	a ref pointing to a tag object that points to a tag object
+	that points to a tree object, etc.
 
 [[def_unmerged_index]]unmerged index::
 	An <<def_index,index>> which contains unmerged
-- 
1.8.3.1