Exceptions inside assertions

Exceptions inside assertions

[Gerd Stolpmann]

Hi, 

I have a problem with exceptions which are raised within the expression of an
assertion, e.g.

assert (raise Not_found)

The current behaviour is that the exception "falls through the assertion" which
may not be appropriate for some cases. For example, consider

assert (Queue.peek queue == current_element)

>From my point of view, the assertion expresses that "queue" has at least one
element and that this element is identical to "current_element". But if the
assertion is violated because the queue is empty, I only get a Queue.Empty
exception, and I do not see the reason for it. Perhaps I even catch
Queue.Empty, and the program continues, which is very hard to find out.

I suggest to introduce a new Assert_failure_by_exception exception to better
report this situation.

Gerd
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Re: Exceptions inside assertions

[Damien Doligez]

>From: Gerd Stolpmann <Gerd.Stolpmann@darmstadt.netsurf.de>
>
>I have a problem with exceptions which are raised within the expression of an
>assertion, e.g.
>
>assert (raise Not_found)
>
>The current behaviour is that the exception "falls through the
>assertion" which may not be appropriate for some cases.

I'd say this is a bug: the doc says Assert_failure is raised whenever
the expression does not evaluate to true.

This will be fixed in the next release.

-- Damien