Comment 3 for bug 919216

> Well, in the case of failing dependencies, it seems like any choice at
> the prompt gives a 0 return value. Is the rationale that 'aptitude
> managed to abort successfully' equals success? If that is the intended
> functionality, then I cannot trust aptitude to give any meaningful
> return value.

In choosing to abort at the prompt the return value of 0 should be considered a bug. Other choices made at the prompt have the effect of changing your instructions, and thus, if the new request succeeds, the return value should indicate that.

> And as far as I can see, the bug you refer to only concerns failing to
> install a specified version. At least that's what it patches.

Both case 2 in the OP and the case in the mentioned Debian bug report
are symptoms of the same underlying problem: failure to find the
specified installation candidate.