git.getModTime panics on nil commit.Author field

[renfredxh]

Ran into this issue in production on sourcegraph.com. Fixing it with a patch that checks if commit.Author is nil but we're not sure if that should ever be the case.

[dmitshur]

/cc @shazow Do you know if it's valid for a go-git.Commit to have a nil value for Author? If so, in what conditions can that happen?

[shazow]

I actually remember adding a TODO to investigate this. https://github.com/shazow/go-vcs/blob/db0a781237d83106d6f48dede25d70aa9842b451/vcs/git/repo.go#L207 Good times.

Not sure what condition this falls under off the top of my head, I just noticed one backend allowed for nil and another did not.

[dmitshur]

I just noticed one backend allowed for nil and another did not.

Which backends are you referring to? There are multiple layers of abstraction, so the word "backend" becomes ambiguous. :P

[shazow]

Two of the three of: go-vcs's libgit2, gitcmd, and gogs' go-git that I forked. (I forget which)