Re: simple-spacer: inappropriate assert; issue 4448 (issue 249820043 by address@hidden)

[Keith OHara]

On Fri, 19 Jun 2015 23:59:11 -0700, <address@hidden> wrote:

> https://codereview.appspot.com/249820043/diff/1/lily/simple-spacer.cc
> File lily/simple-spacer.cc (right):
>
> https://codereview.appspot.com/249820043/diff/1/lily/simple-spacer.cc#newcode199
> lily/simple-spacer.cc:199: programming_error ("misuse of expand_line");
> Any sensible fallback behavior for this "misuse of expand_line"?  If we
> can reliably guess what the intent of the "misuse" is (after all, it
> would appear that the situation comes about from reasonably regular
> input rather than explicit user error), one could just do that and
> forget about the programming error.

These two asserts cannot be triggered in current code, except maybe through 
roundoff error, because the only calls of the function are protected my 
matching conditionals in Simple_spacer::solve()

The third assert is the one that trips (windows-only).


> Is there something reasonably "continuous" one can do so that small
> errors lead to small offsets?

The following line obviously returns a quantity that changes continuously 
across the assert condition,
so I am 90% sure you are defying national stereotypes and using irony.

In that case, yes, I do think the behavior that was being protected against is 
so benign that there need be no traps at all for these conditions.