From b28b1a86c96ba3cd920173c6a55cdbf20fbf265e Mon Sep 17 00:00:00 2001
From: kayomn <kayomn@kayomn.net>
Date: Mon, 6 Nov 2023 22:27:09 +0000
Subject: [PATCH] Fix double free and boxing bugs in VM

---
 debug/app.ona            |  6 +++++-
 source/ona/kym.zig       |  4 ++--
 source/ona/kym/Chunk.zig | 23 +++++++++++++++++++----
 3 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/debug/app.ona b/debug/app.ona
index bb14b64..6920724 100644
--- a/debug/app.ona
+++ b/debug/app.ona
@@ -1,5 +1,9 @@
 
-let test_param = "monkey wrench"
+let wrench = "wrench"
+
+var test_param = "monkey {wrench}"
+
+test_param = "monkey"
 
 let printer = lambda (pfx):
 	@print(test_param)
diff --git a/source/ona/kym.zig b/source/ona/kym.zig
index 69c40fe..7ad0543 100644
--- a/source/ona/kym.zig
+++ b/source/ona/kym.zig
@@ -282,7 +282,7 @@ pub const RuntimeEnv = struct {
 	pub fn get_boxed(self: *RuntimeEnv, boxable: *RuntimeRef) RuntimeError!?*RuntimeRef {
 		return switch (boxable.object().payload) {
 			.boxed => |boxed| if (boxed) |boxed_value| boxed_value.acquire() else null,
-			else => self.raise(error.TypeMismatch, "{typename} is not boxable", .{.typename = boxable.typename()}),
+			else => self.raise(error.TypeMismatch, "{typename} is not box-gettable", .{.typename = boxable.typename()}),
 		};
 	}
 
@@ -624,7 +624,7 @@ pub const RuntimeEnv = struct {
 				boxed.* = if (value) |ref| ref.acquire() else null;
 			},
 
-			else => return self.raise(error.TypeMismatch, "{typename} is not boxable", .{
+			else => return self.raise(error.TypeMismatch, "{typename} is not box-settable", .{
 				.typename = boxable.typename(),
 			}),
 		}
diff --git a/source/ona/kym/Chunk.zig b/source/ona/kym/Chunk.zig
index 7ebb7fb..20be8b5 100644
--- a/source/ona/kym/Chunk.zig
+++ b/source/ona/kym/Chunk.zig
@@ -167,7 +167,14 @@ const Compiler = struct {
 
 			.declaration_get => |declaration_get| {
 				if (get_local_index(environment, declaration_get.declaration)) |index| {
-					return self.chunk.write(expression.line, .{.push_local = index});
+					if (is_declaration_boxed(declaration_get.declaration)) {
+						try self.chunk.write(expression.line, .{.push_local = index});
+						try self.chunk.write(expression.line, .get_box);
+					} else {
+						try self.chunk.write(expression.line, .{.push_local = index});
+					}
+
+					return;
 				}
 
 				if (try self.get_binding_index(environment, declaration_get.declaration)) |index| {
@@ -187,12 +194,19 @@ const Compiler = struct {
 				if (get_local_index(environment, declaration_set.declaration)) |index| {
 					try self.compile_expression(environment, declaration_set.assign, null);
 
-					return self.chunk.write(expression.line, .{.set_local = index});
+					if (is_declaration_boxed(declaration_set.declaration)) {
+						try self.chunk.write(expression.line, .{.push_local = index});
+						try self.chunk.write(expression.line, .set_box);
+					} else {
+						try self.chunk.write(expression.line, .{.set_local = index});
+					}
+
+					return;
 				}
 
 				if (try self.get_binding_index(environment, declaration_set.declaration)) |index| {
-					try self.chunk.write(expression.line, .{.push_binding = index});
 					try self.compile_expression(environment, declaration_set.assign, null);
+					try self.chunk.write(expression.line, .{.push_binding = index});
 
 					if (is_declaration_boxed(declaration_set.declaration)) {
 						try self.chunk.write(expression.line, .set_box);
@@ -730,7 +744,8 @@ pub fn execute(self: *Self, env: *kym.RuntimeEnv, frame: *const kym.Frame) kym.R
 
 				const value = try env.expect(try env.pop_local());
 
-				defer env.discard(box);
+				errdefer env.discard(value);
+
 				try env.set_boxed(box, value);
 			},