expose `panto` to extensions as a require()able module, not a global

1 files changed, 15 insertions, 4 deletions

diff --git a/src/lua_runtime.zig b/src/lua_runtime.zig
index 797b97b..e26d017 100644
--- a/src/lua_runtime.zig
+++ b/src/lua_runtime.zig
@@ -263,7 +263,7 @@ pub const LuaRuntime = struct {
         // so its return value naturally lands above it; calling pcall then
         // consumes both in the right order.
         const L = self.L;
-        _ = c.lua_getglobal(L, "panto");
+        lua_bridge.pushPantoTable(L);
         _ = c.lua_getfield(L, -1, "ext");
         _ = c.lua_getfield(L, -1, "register_tool");
         // Stack: ..., panto, ext, register_tool. Collapse to just
@@ -974,7 +974,7 @@ fn invokeCoroutineSync(
 /// stores into the matching slot.
 fn installRecordResult(self: *LuaRuntime) !void {
     const L = self.L;
-    _ = c.lua_getglobal(L, "panto");
+    lua_bridge.pushPantoTable(L);
     if (c.lua_type(L, -1) != lua_bridge.T_TABLE) {
         c.lua_settop(L, c.lua_gettop(L) - 1);
         return RuntimeError.LuaInitFailed;
@@ -1038,7 +1038,10 @@ fn recordResultC(L: ?*c.lua_State) callconv(.c) c_int {
 /// Stored in the Lua registry under `self.wrapper_ref`.
 fn installWrapperClosure(self: *LuaRuntime) !void {
     const L = self.L;
+    // `panto` is not a global, so the wrapper closes over the table
+    // (passed as an argument) rather than looking it up globally.
     const snippet =
+        \\local panto = ...
         \\return function(idx, handler, input)
         \\  local ok, val = pcall(handler, input)
         \\  panto._record_result(idx, ok, val)
@@ -1049,7 +1052,9 @@ fn installWrapperClosure(self: *LuaRuntime) !void {
         c.lua_settop(L, c.lua_gettop(L) - 1);
         return RuntimeError.LuaInitFailed;
     }
-    if (c.lua_pcallk(L, 0, 1, 0, 0, null) != 0) {
+    // Pass the `panto` table as the chunk's vararg argument.
+    lua_bridge.pushPantoTable(L);
+    if (c.lua_pcallk(L, 1, 1, 0, 0, null) != 0) {
         logTopAsError(L, "panto-lua: wrapper closure failed to evaluate");
         c.lua_settop(L, c.lua_gettop(L) - 1);
         return RuntimeError.LuaInitFailed;
@@ -1153,7 +1158,12 @@ fn freeResults(results: []panto.ToolCallResult) void {
 }
 
 fn writeTempScript(dir: Io.Dir, name: []const u8, source: []const u8) ![]const u8 {
-    try dir.writeFile(testing.io, .{ .sub_path = name, .data = source });
+    // `panto` is not a global; extensions reach it via `require('panto')`.
+    // Prepend the require so these tests exercise the real preload path
+    // without each script repeating the boilerplate.
+    var src_buf: [16384]u8 = undefined;
+    const data = try std.fmt.bufPrint(&src_buf, "local panto = require(\"panto\")\n{s}", .{source});
+    try dir.writeFile(testing.io, .{ .sub_path = name, .data = data });
     var buf: [std.fs.max_path_bytes]u8 = undefined;
     const n = try dir.realPathFile(testing.io, name, &buf);
     return testing.allocator.dupe(u8, buf[0..n]);
@@ -1428,6 +1438,7 @@ test "directory-style extension can require sibling modules" {
     try tmp.dir.writeFile(testing.io, .{
         .sub_path = "ext/init.lua",
         .data =
+        \\local panto = require("panto")
         \\local util = require("util")
         \\panto.ext.register_tool {
         \\  name = "shout", description = "uppercase + bang",