I'm surprised by nonchalance about bad inputs evoking bad program behavior.
That attitude may have been excusable 50 years ago. By now, though, we have
seen so much malicious exploitation of open avenues of "undefined behavior"
that we can no longer ignore bugs that "can't happen when using the tool
correctly". Mature software should not brook incorrect usage.
"Bailing out near line 1" is a sign of defensive precautions. Crashes and
unjustified output betray their absence.
I commend attention to the LangSec movement, which advocates for rigorously
enforced separation between legal and illegal inputs.
Doug