$ docker run --rm --name validator-giflib-usage-giflib-tools-giffix-corrupt-gcb-byte-2536 -t --mount type=bind,src=/tmp/validator-status-giflib-usage-giflib-tools-giffix-corrupt-gcb-byte,dst=/validator/status validator-giflib-shared bash -lc 'set -euo pipefail
/validator/tests/_shared/install_override_debs.sh
exec /validator/tests/_shared/run_library_tests.sh "$@"' validator-testcase giflib usage-giflib-tools-giffix-corrupt-gcb-byte -- bash -c 'PS4=$1; shift; set -x; source "$@"' validator-xtrace '__VALIDATOR_XTRACE__ ' /validator/tests/giflib/tests/cases/usage/usage-giflib-tools-giffix-corrupt-gcb-byte.sh
no override packages found; continuing with apt originals
import sys
path = sys.argv[1]
with open(path, "r+b") as fh:
    fh.seek(-1, 2)
    last = fh.read(1)
    if last != b"\x3B":
        sys.exit(f"fixture does not end with 0x3B trailer, got {last!r}")
    fh.seek(0, 2)
    fh.write(b"\x00" * 96)
' /tmp/validator-tmp/dirty.gif
import sys
with open(sys.argv[1], "rb") as fh:
    fh.seek(-1, 2)
    sys.stdout.write("%02x" % fh.read(1)[0])
' /tmp/validator-tmp/fixed.gif