Fix infinite loop when failed to find path for volume on Windows

[woct0rdho]

When getVolumePaths returns an error, we should not just continue the for loop. We should skip processMountsForVolume, then update volNameBuf using procFindNextVolumeW. Otherwise it would loop forever.

I discovered this bug when running wandb, which uses gopsutil to collect system info, and there is a virtual CD program on my machine that leaves a stale volume that causes an error in getVolumePaths. It's discussed in #1911 but not really fixed yet.

[StefanoBalzarottiNozomi]

thanks for the fix, but are you able to add a test to simulate the problem ?

[woct0rdho]

I've refactored it to allow inserting custom functions getVolumePathsFn, processMountsForVolumeFn, findNextVolumeFn, then test how many times these functions are called in processVolumeLoopWith.

I'm not very familiar with Go. In Python people would monkey-patch getVolumePaths to test it, but I'm not sure if there is a way to do so in Go.

[shirou]

Thank you for your PR. The fix for the infinite loop is a nice catch!

I appreciate you adding the test based on the review feedback. However, the test only verifies the if/else control flow, which is fairly straightforward. I think changing the function signature to 9 arguments just for this test is a bit much.

Sorry for the extra work, but could you revert to your original minimal fix? That's all we need here. Thanks!

[woct0rdho]

Ok I've reverted the test and kept it a minimal change.

[shirou]

Thank you so much!