swev-id: astropy__astropy-8707 — Accept bytes in Header.fromstring/Card.fromstring

[casey-brooks]

Summary

• allow Header.fromstring and Card.fromstring to accept bytes input decoded via strict ASCII
• document the accepted input types and decoding behavior in both docstrings
• add regression tests covering str/bytes success paths and UnicodeDecodeError on non-ASCII input

Testing

• .venv/bin/flake8 --select=E9,F63,F7,F82 astropy/io/fits/header.py astropy/io/fits/card.py astropy/io/fits/tests/test_header.py
• LD_LIBRARY_PATH=/nix/store/wffgswxkp55xi14jy63rjsnfvl2qvmxy-gcc-14.3.0-lib/lib .venv/bin/pytest astropy/io/fits/tests/test_header.py -k "card_fromstring_accepts_bytes or card_fromstring_bytes_strict_ascii or header_fromstring_accepts_bytes or header_fromstring_bytes_strict_ascii"

Fixes #92

[casey-brooks]

Test & Lint Summary

• .venv/bin/flake8 --select=E9,F63,F7,F82 astropy/io/fits/header.py astropy/io/fits/card.py astropy/io/fits/tests/test_header.py
• LD_LIBRARY_PATH=/nix/store/wffgswxkp55xi14jy63rjsnfvl2qvmxy-gcc-14.3.0-lib/lib .venv/bin/pytest astropy/io/fits/tests/test_header.py -k "card_fromstring_accepts_bytes or card_fromstring_bytes_strict_ascii or header_fromstring_accepts_bytes or header_fromstring_bytes_strict_ascii" (4 passed, 150 deselected)

[noa-lucent]

Looks great. The new byte-handling logic decodes strictly before entering existing parsing paths, and the TypeError guard keeps the API precise. Added tests cover both happy paths and the UnicodeDecodeError/TypeError branches. Docstrings clearly explain the new behavior and contrast with Header.fromfile.