[ bug ] Crashes on extending file of same name to source

[yonas]

Describe The Bug

Accidentally trying to extend a file of the same name as the source will crash cargo-make.

This should be handled more gracefully.

To Reproduce

Add the following to a file Makefile.toml.

extend = { path = "Makefile.toml", optional = false }

Error Stack

thread 'main' has overflowed its stack
fatal runtime error: stack overflow
fish: Job 1, 'cargo make ping --verbose' terminated by signal SIGABRT (Abort)