Allow for default constructed parcel instances to be moved

[hkaiser]

This fixes #1790: assertion 'action_.get()' failed: HPX(assertion_failure) when running Octotiger with pull request 1786

[sithhell]

The asserts were put in for sanity checks. A parcel without an action doesn't make a lot of sense. There might be more behind #1790, removing those asserts might just cover them up

[hkaiser]

We move default constructed parcels, for those these asserts will fire.

[hkaiser]

It would make more sense to check for an action only if we access it in order to invoke it, instead.

[sithhell]

Am 09.10.2015 1:41 vorm. schrieb "Hartmut Kaiser" <notifications@github.com

We move default constructed parcels, for those these asserts will fire.

Can you show me where this is happening? I find it highly suspicious that
those suddenly fire, I would like to know why this of suddenly happening
before removing it.

[sithhell]

Am 09.10.2015 1:42 vorm. schrieb "Hartmut Kaiser" <notifications@github.com

It would make more sense to check for an action only if we access it in
order to invoke it, instead.

Why? This catches a potential error as early as possible, checking on each
access sounds excessive.

[hkaiser]

It would make more sense to check for an action only if we access it in order to invoke it, instead.

Why? This catches a potential error as early as possible, checking on each access sounds excessive.

Let's add a proper check whether the parcel is valid, instead. Just the absence of a valid action does not tell anything.

[hkaiser]

Can you show me where this is happening? I find it highly suspicious that
those suddenly fire, I would like to know why this of suddenly happening
before removing it.

We do that in several places, for instance here.

[sithhell]

The callback takes the parcel by reference, no?
In any case, I am just very curious why this assert hasn't fired so far on master. I think #1790 has a deeper underlying problem which needs to be fixed instead. We can of course move the assert to check on each access of the action, but as said, this sounds excessive and unnecessary to me.

[hkaiser]

We can of course move the assert to check on each access of the action, but as said, this sounds excessive and unnecessary to me.

That's done already here.

[hkaiser]

The latest commit adds more comprehensive sanity checking to parcels not relying on the action only.

[sithhell]

LGTM, thanks!