[[format_write]] is broken

[Kein]

Operating System

Windows

What's the issue you encountered?

I'mHex v 1.33.0

u8               SaveHash      [[format_write("WriteHash")]];

// Hash handling
fn WriteHash(str v) { return 12; };

Result: nothing happens. Completely nothing, not even user-input value being written as-is.

How can the issue be reproduced?

See above.

ImHex Version

1.33.0

ImHex Build Type

• [X] Nightly or built from sources

Installation type

manual

Additional context?

format_read works

[EtiTheSpirit]

I can reproduce this on 1.33.2 Release installed via the non-portable .msi installer on Windows

I tested this myself and as tested by OP, the return value of the function is entirely ignored and discarded in all cases. In my case I am using a custom struct rather than u8, but the same issue applies here.

I will also add that nothing is output into the log console at debug level with respect to the pattern data.

Edit 12 July 2024: I've just decided to come back to this since I ran into it on accident again. There's some additional quirks I noticed.

1. Adding a std::print(txt) (where txt is the string arg to the function) does nothing if the argument type is ref str txt, but works fine if it is just str txt.
2. I was attempting to return a custom object type but realized this does not work. Is this intentional?
3. I followed this up by trying to return a char array but this just placed corrupted data in, even if I wrote to the array in a loop (bug? it always seemed to be the same data, I was using std::string::at)
4. I did get it to work by returning a string value. My struct is a string value prefixed with a 16 bit length, so I just prepended two spaces to the result string then replaced [0] and [1] of the string with the length bytes. The issue I ran into now is that it can't seem to insert or remove bytes.