Requiring goal to contain only one statement.

Previously, the parser read the first statement of the goal as its
precondition, but didn’t check that it was properly terminated with a
closing parenthesis. This allowed arbitrary text to be included within
the goal description without error, which was incorrect.

This commit fixes this issue and adds a corresponding unit test.

lib/pddl/src/pddl/detail/parsing/Problem.cpp

@@ -283,6 +283,7 @@ void ProblemParser::parseGoalSection(ast::Problem &problem)
 	VariableStack variableStack;
 
 	problem.goal = parsePrecondition(m_context, astContext, variableStack);
+	tokenizer.expect<std::string>(")");
 
 	skipSection(tokenizer);
 }

lib/pddl/tests/TestIssues.cpp

@@ -84,4 +84,13 @@ TEST_CASE("[PDDL parser issues] Check past issues", "[PDDL parser issues]")
 
 		CHECK(!containsInvalidFact);
 	}
+
+	// Check that goal contains just one precondition and is correctly terminated by “)”
+	SECTION("goal may contain only one precondition")
+	{
+		const auto domainFile = fs::path("data") / "issues" / "issue-11.pddl";
+		context.tokenizer.read(domainFile);
+
+		CHECK_THROWS(pddl::parseDescription(context));
+	}
 }

tests/data/issues/issue-11.pddl

@@ -0,0 +1,15 @@
+; tests that “imply” statements in preconditions are correctly reduced
+(define (domain test-normalization)
+	(:predicates
+		(test-predicate-0))
+)
+
+(define (problem test-normalization)
+	(:domain test-normalization)
+
+	(:init
+		(test-predicate-0))
+
+	(:goal
+		(test-predicate-0)
+		(error)))