Update object_find to accept more object spec types

libwyag.py

@@ -284,7 +284,34 @@ def cat_file(repo, obj, fmt=None):
     sys.stdout.buffer.write(obj.serialize())
 
 def object_find(repo, name, fmt=None, follow=True):
-    return name
+    sha = object_resolve(repo, name)
+
+    if not sha:
+        raise Exception(f"No such reference {name}")
+
+    if len(sha) > 1:
+        raise Exception(f"Ambiguous reference {0}: Candidates are:\n - {1}.".format(name, "\n - ".join(sha)))
+
+    sha = sha[0]
+
+    if not fmt:
+        return sha
+
+    while True:
+        obj = object_read(repo, sha)
+
+        if obj.fmt == fmt:
+            return sha
+
+        if not follow:
+            return None
+
+        if obj.fmt == b'tag':
+            sha = obj.kvlm[b'object'].decode("ascii")
+        elif obj.fmt == b'commit' and fmt == b'tree':
+            sha = obj.kvlm[b'tree'].decode("ascii")
+        else:
+            return None
 
 argsp = argsubparsers.add_parser(
     "hash-object",