UnicodeEncodeError when encoding lone surrogates with utf-16 and surrogatepass handler

[kgonia]

When attempting to encode a string containing a lone surrogate (e.g., \ud83d) using the utf-16 codec and the surrogatepass error handler, GraalPy raises a UnicodeEncodeError.

def main():
    text = "\ud83d"
    text.encode("utf-16", "surrogatepass").decode("utf-16", "replace")
if __name__ == "__main__":
    main()

throws UnicodeEncodeError: 'utf_16' codec can't encode character '\ud83d' in position 0: malformed input when run on graalpy-25.0.1

while running normaly on python

I encountered this issue when I was trying to build graalpy wheel for tiktoken

[msimacek]

Thank you for the report, I was able to reproduce the bug and I'll look into it soon