Missing return value in graph.h (Undefined Behavior?)

[dnezam]

Hello,

while trying to implement an algorithm using your library, I have come across issues when trying to use std::move on a symmetric graph, namely bad_alloc or stack smashing.

After running the code with sanitizers (address and undefined), I got the following message:
gbbs/graph.h:150:20: runtime error: execution reached the end of a value-returning function without returning a value
It seems that the move assignments in graph.h are missing return *this. This might be undefined behaviour, but I am not sure as I am not too familiar with C++. After adding return *this to the end of symmetric_graph& operator=(symmetric_graph&& other) noexcept , the algorithm ran without crashing.

Let me know if you'd like more details regarding when exactly these issues occurred.

Thanks,
Daniel

[Qwendu]

Falling off the end of a function, if it has a non void return value, is Undefined Behaviour in C++.

This happens in gbbs/graph.h
in methods:
gbbs/graph.h:150 symmetric_graph& operator=(symmetric_graph &&other)
gbbs/graph.h:312 symmetric_ptr_graph& operator=(symmetric_ptr_graph &&other)
gbbs/graph.h:475 asymmetric_graph& operator=(asymmetric_graph &&other)
gbbs/graph.h:587 asymmetric_ptr_graph& operator=(asymmetric_ptr_graph &&other)

These seem to be copy and past mistake from the corresponding move constructors.

Cheers!

[tomtseng]

Thanks for the bug report, does adding a return *this; to the end of each of those functions fix it? I just merged a pull request #78 adding those return statements

[dnezam]

Thanks for the quick response! I added return *this; to the function that I used, and now it works :)