Modified inputs cause validation to fail

[Tagl]

We have a problem with non-standard input.

Running verifyproblem on it results in a crash due to the following error:

Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/root/problemtools/problemtools/verifyproblem.py", line 2225, in <module>
    main()
  File "/root/problemtools/problemtools/verifyproblem.py", line 2209, in main
    errors, warnings = prob.check()
                       ^^^^^^^^^^^^
  File "/root/problemtools/problemtools/verifyproblem.py", line 2061, in check
    item.check(context)
  File "/root/problemtools/problemtools/verifyproblem.py", line 1192, in check
    if modified_input_validates(applicable, modifier):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/root/problemtools/problemtools/verifyproblem.py", line 1169, in modified_input_validates
    infile_data = infile.read()
                  ^^^^^^^^^^^^^
  File "<frozen codecs>", line 322, in decode
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x8a in position 2: invalid start byte

This is not very nice for us.
The inputs are correct and completely fine according to the problem statement.

Perhaps it should just print a warning or fail silently if the input is not UTF-8

[Matistjati]

All text files for a problem must be UTF-8 encoded and not have a byte-order mark (BOM).

https://www.kattis.com/problem-package-format/spec/legacy.html

Even if this is fixed, I would imagine more things might break?

[Tagl]

No, it works fine if you add a try except around this and skip modification in this exceptional case.