fix memory leak on string arguments

src/lang.zig

@@ -479,6 +479,21 @@ pub const CommandList = struct {
     pub fn deinit(self: *Self) void {
         for (self.list.items) |cmd_ptr| {
             self.list.allocator.destroy(cmd_ptr);
+            inline for (@typeInfo(Command.Tag).Enum.fields) |field| {
+                if (cmd_ptr.tag == @field(Command.Tag, field.name)) {
+                    const actual_tag =
+                        @field(Command.Tag, field.name);
+                    // if we find a match on the tag, we can get the type
+                    const typ = Command.tagToType(actual_tag);
+
+                    inline for (@typeInfo(typ).Struct.fields) |cmd_field| {
+                        switch (cmd_field.field_type) {
+                            []u8, []const u8 => self.list.allocator.destroy(@field(typ, cmd_field.name)),
+                            else => {},
+                        }
+                    }
+                }
+            }
         }
         self.list.deinit();
     }
@@ -561,7 +576,7 @@ pub const Lang = struct {
                     f32 => try std.fmt.parseFloat(f32, arg),
                     u64 => try std.fmt.parseInt(u64, arg, 10),
                     usize => try std.fmt.parseInt(usize, arg, 10),
-                    []const u8 => arg,
+                    []const u8 => @as([]const u8, try self.allocator.dupe(u8, arg)),
                     else => @compileError("parameter struct has unsupported type " ++ @typeName(cmd_field.field_type)),
                 };
 
@@ -586,7 +601,7 @@ pub const Lang = struct {
                     usize => try std.fmt.parseInt(usize, arg, 10),
                     i32 => try std.fmt.parseInt(i32, arg, 10),
                     f32 => try std.fmt.parseFloat(f32, arg),
-                    []const u8 => arg,
+                    []const u8 => @as([]const u8, try self.allocator.dupe(u8, arg)),
                     else => @compileError("Invalid parameter type (" ++ @typeName(cmd_field.field_type) ++ ") left on command struct " ++ @typeName(command_struct) ++ "."),
                 };
 

src/main.zig

@@ -40,6 +40,8 @@ pub fn doRepl(allocator: *std.mem.Allocator, args_it: anytype) !void {
     var stdout_file = std.io.getStdOut();
     const stdout = &stdout_file.writer();
     const scri_path = try (args_it.next(allocator) orelse @panic("expected scri path"));
+    errdefer allocator.free(scri_path);
+    defer allocator.free(scri_path);
 
     var file_read_opt: ?std.fs.File = std.fs.cwd().openFile(scri_path, .{}) catch |err| blk: {
         if (err == error.FileNotFound) break :blk null;
@@ -54,11 +56,9 @@ pub fn doRepl(allocator: *std.mem.Allocator, args_it: anytype) !void {
     defer lang.deinit();
 
     if (total_bytes > 0) {
-        // this MUST BE long lived (a reference to it is kept inside
-        // existing_cmds, and then passed along to cmds),
-        // we can't defer them here
         var scri_existing = try allocator.alloc(u8, total_bytes);
         _ = try file_read_opt.?.read(scri_existing);
+        defer allocator.free(scri_existing);
 
         // we can't defer this directly because we copy the
         // Command pointers to the cmds list. running deinit() directly