Double free or corruption error when trying to use libfive

[gsohler]

Description

[Description of the issue]
When trying to use internals of livfive i get a double free or corruption error, segfault
[Steps to reproduce]

I use this code to evaluate the tree only once:

double sdf_func(libfive::Tree &tr, Vector3d pt)
{
ArrayEvaluator e((Tree(tr))); <- segfaults here
// double xx =e.value({pt[0], pt[1], pt[2]});
}

Reading the internet i understand, why its not allowed to use a local variable for use in make_shared in ArrayEvaluator.cpp
(the memory will be freed once in local scope and once when the std_shared ptr is not used anymore.
However, in this case i dont know how to fix it, because "Tree" is a variable and not a ptr to variable.

[What did you expect to happen? What happened? All the time?]
It should return a value and not segfault.
Are there any other initialisation steps required to make simple ArrayEvaluator Class not crash ?

[Are there any error messages printed to the console?]
Yes:
double free or corruption (out)
Aborted (core dumped)

Versions

• Operating system: FC37
• libfive commit hash:
  • Is this the latest commit to master? no
• Qt version (if applicable): qt5

Additional Information

Any additional information, configuration or data that might be necessary to reproduce the issue.

[lf94]

@gsohler It seems we may be hitting the same error :)

[gsohler]

This error dominantly happens, when the meshing result from Mesh::render is void.
Issue is that the data returned by Mesh::render() already appears freed. When the returned mesh gets out of scope it gets freed
again and double free error is thrown . Could there be some issue with the Mesh desctructor ?

Is there a reason why Mesh::render returns an unique_ptr and not a shared_ptr ?
I have replaced unique_ptr to shared_ptr 12 times and once replaced release() by get()
and it workes much more stable in my place.
Would you accept a PR ?

[lf94]

Nice work @gsohler :)