diff --git a/lib/std/json.zig b/lib/std/json.zig index 1c4cbdf5cb..42c4d98d32 100644 --- a/lib/std/json.zig +++ b/lib/std/json.zig @@ -1745,7 +1745,37 @@ pub fn parseFree(comptime T: type, value: T, options: ParseOptions) void { .Struct => |structInfo| { inline for (structInfo.fields) |field| { if (!field.is_comptime) { - parseFree(field.type, @field(value, field.name), options); + var should_free = true; + if (field.default_value) |default| { + switch (@typeInfo(field.type)) { + // We must not attempt to free pointers to struct default values + .Pointer => |fieldPtrInfo| { + const field_value = @field(value, field.name); + const field_ptr = switch (fieldPtrInfo.size) { + .One => field_value, + .Slice => field_value.ptr, + else => unreachable, // Other pointer types are not parseable + }; + const field_addr = @ptrToInt(field_ptr); + + const casted_default = @ptrCast(*const field.type, @alignCast(@alignOf(field.type), default)).*; + const default_ptr = switch (fieldPtrInfo.size) { + .One => casted_default, + .Slice => casted_default.ptr, + else => unreachable, // Other pointer types are not parseable + }; + const default_addr = @ptrToInt(default_ptr); + + if (field_addr == default_addr) { + should_free = false; + } + }, + else => {}, + } + } + if (should_free) { + parseFree(field.type, @field(value, field.name), options); + } } } }, diff --git a/lib/std/json/test.zig b/lib/std/json/test.zig index 7f87b2fa52..3c9414a59c 100644 --- a/lib/std/json/test.zig +++ b/lib/std/json/test.zig @@ -2246,6 +2246,31 @@ test "parse into struct with default const pointer field" { try testing.expectEqual(T{}, try parse(T, &ts, .{})); } +const test_default_usize: usize = 123; +const test_default_usize_ptr: *align(1) const usize = &test_default_usize; +const test_default_str: []const u8 = "test str"; +const test_default_str_slice: [2][]const u8 = [_][]const u8{ + "test1", + "test2", +}; + +test "freeing parsed structs with pointers to default values" { + const T = struct { + int: *const usize = &test_default_usize, + int_ptr: *allowzero align(1) const usize = test_default_usize_ptr, + str: []const u8 = test_default_str, + str_slice: []const []const u8 = &test_default_str_slice, + }; + + var ts = json.TokenStream.init("{}"); + const options = .{ .allocator = std.heap.page_allocator }; + const parsed = try json.parse(T, &ts, options); + + try testing.expectEqual(T{}, parsed); + + json.parseFree(T, parsed, options); +} + test "parse into struct where destination and source lengths mismatch" { const T = struct { a: [2]u8 }; var ts = TokenStream.init("{\"a\": \"bbb\"}");