command_map: don't crash on empty arguments

2 files changed, 15 insertions, 5 deletions

diff --git a/nihil/command_map.ccm b/nihil/command_map.ccm
index 5aeb7c8..279c43e 100644
--- a/nihil/command_map.ccm
+++ b/nihil/command_map.ccm
@@ -71,6 +71,9 @@ struct node {
 	// Run the handler for this node.
 	auto invoke(Context const &ctx, int argc, char **argv) const -> int
 	{
+		if (argc == 0)
+			throw usage_error("incomplete command");
+
 		// Look for a subcommand with argv[0].
 		auto it = commands.find(argv[0]);
 		if (it == commands.end())
@@ -85,9 +88,6 @@ struct node {
 		--argc;
 		++argv;
 
-		if (argc == 0)
-			throw usage_error("incomplete command");
-
 		// Otherwise, continue recursing.
 		return child.invoke(ctx, argc, argv);
 	}
diff --git a/nihil/tests/command_map.cc b/nihil/tests/command_map.cc
index 75b6f0d..c8cd1a1 100644
--- a/nihil/tests/command_map.cc
+++ b/nihil/tests/command_map.cc
@@ -25,10 +25,20 @@ TEST_CASE("command_map: basic", "[command_map]")
 		"cmd", "sub1", nullptr
 	};
 	auto argv = const_cast<char **>(args.data());
-	nihil::dispatch_command(0, args.size(), argv);
+	nihil::dispatch_command(0, args.size() - 1, argv);
 	REQUIRE(cmd_sub1_called == true);
 }
 
+TEST_CASE("command_map: no arguments", "[command_map]")
+{
+	auto args = std::vector<char const *>{
+		nullptr
+	};
+	auto argv = const_cast<char **>(args.data());
+	REQUIRE_THROWS_AS(nihil::dispatch_command(0, args.size() - 1, argv),
+			  nihil::usage_error);
+}
+
 TEST_CASE("command_map: unknown command", "[command_map]")
 {
 	auto args = std::vector<char const *>{
@@ -36,6 +46,6 @@ TEST_CASE("command_map: unknown command", "[command_map]")
 	};
 	auto argv = const_cast<char **>(args.data());
 
-	REQUIRE_THROWS_AS(nihil::dispatch_command(0, args.size(), argv),
+	REQUIRE_THROWS_AS(nihil::dispatch_command(0, args.size() - 1, argv),
 			  nihil::usage_error);
 }