Fix checkArgument logical error (#18)

Author: thsackos

CHANGELOG.md

@@ -0,0 +1,16 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [2.0.0] - 2025-05-21
+
+### Fixed
+
+- Corrected a logic error causing the `Lua.checkArgument()` function to incorrectly error on a passing condition.
+    - Refer to [bug: checkArgument has inverse logic #17](https://github.com/sackosoft/zig-luajit/issues/17)
+
+[2.0.0]: https://github.com/sackosoft/zig-luajit/compare/v1.5.4...v2.0.0
+[1.5.4]: https://github.com/sackosoft/zig-luajit/releases/tag/v2.0.0

build.zig.zon

@@ -1,7 +1,7 @@
 .{
     .name = .luajit,
     .fingerprint = 0xda4bba66d285c19c,
-    .version = "1.5.4",
+    .version = "2.0.0",
     .dependencies = .{
         .luajit_build = .{
             .url = "git+https://github.com/sackosoft/zig-luajit-build#d75c20acaa4df39f51187926fa9d98e4e5231064",

src/root.zig

@@ -2352,8 +2352,9 @@ pub const Lua = opaque {
     /// Refer to: https://www.lua.org/manual/5.1/manual.html#luaL_argcheck
     /// Stack Behavior: `[-0, +0, v]`
     pub fn checkArgument(lua: *Lua, condition: bool, arg_n: i32, extra_message: ?[:0]const u8) void {
-        if (condition) {
+        if (!condition) {
             _ = c.luaL_argerror(asState(lua), arg_n, if (extra_message) |m| m else null);
+            unreachable;
         }
     }
 
@@ -4887,7 +4888,7 @@ test "checkArgument() should return error when argument is invalid and succeed w
     const T = struct {
         fn EchoInteger(l: *Lua) callconv(.c) i32 {
             const val = l.toInteger(1);
-            l.checkArgument(val != 42, 1, "FOOBAR");
+            l.checkArgument(val == 42, 1, "FOOBAR");
             l.pushInteger(val);
             return 1;
         }
@@ -4966,7 +4967,7 @@ test "checkArgument() should return handle null message" {
     const T = struct {
         fn EchoInteger(l: *Lua) callconv(.c) i32 {
             const val = l.toInteger(1);
-            l.checkArgument(val != 42, 1, null);
+            l.checkArgument(val == 42, 1, null);
             l.pushInteger(val);
             return 1;
         }