Re: next assertion found (ldo.c:679: lua_resume: L->nCcalls == ((from) ? from->nCcalls : 0))

[Coda Highland <chighland@...>]

On Wed, Jul 20, 2016 at 3:51 AM, nobody <nobody+lua-list@afra-berlin.de> wrote:
> My "fuzzer" (for lack of a better word) has become too clever for its
> own good and started setting per-line debug hooks that error(),
> producing too many spurious "crashes".  So I locked it away in a
> coroutine... and it immediately crashed.  Oh well. :-)
>
> A lucky random seed got me
> .....coroutine.resume(table.unpack(debug.getregistry())).....,
> which translates into:
>
>
> -- begin test case --
> A = coroutine.running( )
> B = coroutine.create( function( )  coroutine.resume( A )  end )
> coroutine.resume( B )
> -- end test case --
>
> Wrapping print() around the resumes, you get (with lua_assert #defined):
>   false    cannot resume non-suspended coroutine
>   lua.debug: ldo.c:679: lua_resume: Assertion
>     `L->nCcalls == ((from) ? from->nCcalls : 0)' failed.
>   Aborted(134)
> i.e. the resume of A fails with the expected error message, but the
> resume of B runs into the assertion while returning.
>
> (Previous problems in that corner: [1] (and maybe more))
>
>
> Notably (& furthermore), coroutine.wrap will not hit the assertion,
> instead the main thread (A) is claimed to be both dead _and_ alive:
>
> -- begin test case #2 --
> local co = coroutine
> A = co.running( )
> co.wrap( function( )
>   print( co.resume( A ) )  --> false, "cannot resume dead coroutine"
>   print( co.status( A ) )  --> "normal"
> end )( )
> -- end test case #2 --
>
>
> -- Marco
>
> [1]: http://lua-users.org/lists/lua-l/2013-10/msg00745.html
>

Congratulations, you've discovered Schroedinger's Coroutine!

/s/ Adam