GDScript: Improve validation and documentation of @export_flags
#72493
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dalexeev
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| return false; | ||
| } | ||
| int64_t value = t[1].to_int(); | ||
| if (value < 1 || value >= (1LL << max_flags)) { |
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const int64_t max_flags = 32;
int64_t value = t[1].to_int();
value >= (1LL << max_flags)I'm not sure if this is correct.
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1LL << max_flags should be 4294967296 (2^32) which is correct, since the underlying type is a 32-bit integer. The >= comparison is also correct, since the value needs to be less than the maximum; otherwise, it would overflow and become 0.
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I'm not sure if int_64t is needed for the constant 32, but I haven't found another way to satisfy CI (tests on multiple platforms have failed).
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The value 1 << 32 doesn't fit in an 32-bit integer. So I'd say it needs to be stored in a int64_t. As for the max_flags constant, I don't think it needs to be int64_t, unless the compiler is complaining about mixing types in bitwise operations.
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It's all unsigned no? Usually for bitwise operations we use 1U << flags where flags is uint64_t.
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The 2^32 value would still not fit in a 32-bit unsigned integer. It will fit in both a signed and unsigned 64-bit integer. I don't know if it matters in C++ if the 64-bit integer is signed, but yes flags usually are unsigned.
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modules/gdscript/gdscript_parser.cpp
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| if (p_annotation->name == SNAME("@export_flags") && p_annotation->resolved_arguments.size() > max_flags) { | ||
| push_error(vformat(R"(The argument count limit for "@export_flags" is exceeded (%d/%d).)", p_annotation->resolved_arguments.size(), max_flags), p_annotation); | ||
| return false; | ||
| } |
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I think this code is no longer needed? Since the flag values are already checked below, and (in theory) there can be more than 32 arguments (different combinations of flags)?
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The value of each argument can't exceed 32^2 2^32 because the underlying type is a 32-bit integer. So this error is still useful because it helps avoid exceeding this limit when the arguments don't specify their value, although it could be improved.
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No, I mean something like:
A:1,B:2,C:4,D:8,E:16,F:32,G:64,<X>
Where <X> is all combinations of 3 flags. C(7,3) = 7! / (3! * 4!) = 35. So there are 7 + 35 = 42 arguments in total. This is greater than 32, but each of the arguments does not exceed the allowed value.
The only thing missing from the check below is the calculation of an auto value if :number is not specified.
Note: I haven't checked how the inspector handles this.
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My response was addressing your question I think this code is no longer needed?. I was thinking it was still needed for the case when values are not specified because it will increase the values automatically so the 33rd argument will exceed 2^32 (4294967296). But I totally missed that you also said Since the flag values are already checked below.
I think, when the value is not specified, this check would give a better error. Otherwise, it may be a bit confusing for users to get Invalid argument %d of annotation "@export_flags": The flag value must be at least 1 and at most 2 ** %d - 1. when they didn't specify any value.
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I think we can finalize this PR, and discuss further improvements separately.
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@export_flags(\
"F00:1", "F01:1", "F02:1", "F03:1",
"F04:1", "F05:1", "F06:1", "F07:1",
"F08:1", "F09:1", "F10:1", "F11:1",
"F12:1", "F13:1", "F14:1", "F15:1",
"F16:1", "F17:1", "F18:1", "F19:1",
"F20:1", "F21:1", "F22:1", "F23:1",
"F24:1", "F25:1", "F26:1", "F27:1",
"F28:1", "F29:1", "F30:1", "F31:1",
"F32:2", "F33:4", "F34:8", "F35:16"
) var test
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|
Thanks! |
@export_flagssupports specifying other values with a colon, just like@export_enum. See the comment.