From 6ce94264f3449fd5c18a9437c82515e4144b07ff Mon Sep 17 00:00:00 2001
From: Victor Paleologue <victor.paleologue@softbankrobotics.com>
Date: Thu, 11 Jun 2020 15:07:56 +0200
Subject: [PATCH] [issue1030] more explicit error when parsing an empty goal

---
 CHANGES.md                                     | 3 ++-
 src/translate/pddl_parser/parsing_functions.py | 4 +++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index 93910baf3e..328f491cdc 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -11,7 +11,8 @@ after the corresponding tracker issues.
 
 ## Changes since the last release
 
-- none yet
+- Better error message for empty goal.
+<http://issues.fast-downward.org/issue1030>
 
 ## Fast Downward 22.06
 
diff --git a/src/translate/pddl_parser/parsing_functions.py b/src/translate/pddl_parser/parsing_functions.py
index fdc0b9dc80..70ffc0d40f 100644
--- a/src/translate/pddl_parser/parsing_functions.py
+++ b/src/translate/pddl_parser/parsing_functions.py
@@ -460,7 +460,9 @@ def parse_task_pddl(task_pddl, type_dict, predicate_dict):
     yield initial
 
     goal = next(iterator)
-    assert goal[0] == ":goal" and len(goal) == 2
+    assert goal[0] == ":goal" and len(goal) == 2 and goal[1], (
+            "missing or empty goal"
+        )
     yield parse_condition(goal[1], type_dict, predicate_dict)
 
     use_metric = False