go mod graph is an invaluable tool for debugging module problems. It allows us to see problems deep into our transitive dependencies. However, it completely falls over if there is a single issue somewhere in the graph, and if that issue is not at the root module it's quite hard to debug transitive dependency problems.

Consider, for example:

$ go mod graph
go: finding github.com/kr/pty v1.1.7
go: github.com/kr/pty@v1.1.7: unknown revision v1.1.7
go: error loading module requirements
$

It would be ideal if the go mod graph command traversed and printed as much of the graph as possible, and indicated which nodes were problematic. For example:

$ go mod graph
A B
B C
C github.com/kr/pty@v1.1.7--ERROR
go: github.com/kr/pty@v1.1.7: unknown revision v1.1.7
go: error loading module requirements

(last two lines are STDERR, first three are STDOUT)