[Issue 17650] [REG v2.075.0 b1-b4] std.getopt range violation

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=17650

--- Comment #7 from Jon Degenhardt <jrdemail2000-dlang at yahoo.com> ---
(In reply to ZombineDev from comment #6)
> The error doesn't make sense to me. @safe adds bounds checks where there are
> none only when building with -release. I.e. if we're not building with
> -release, there shouldn't be any change in behavior - bounds checking should
> already be present (-boundscheck defaults to 'on' in that case). Am I
> missing something?

There was already an existing range violation, one that didn't have a unit test
in the std.getopt module. Adding @safe to the function turned on bounds
checking in debug mode. I had a unit test in my own code (not std.geopt) that
triggered the out-of-bounds case. This unit test didn't get run until I
actually ran my own unit tests with the new code.

The out-of-bounds case occurs when there is an command line argument that is a
single dash. e.g.

   $ myprogram -x a  # okay
   $ myprogram -x -  # out-of-bounds

In the single dash case there's an attempt to access one character past it.
Kind of understandable there wasn't a unit test for this originally. If you
want to see the sequence that led to adding @safe read
https://github.com/dlang/phobos/pull/5347.

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