Debugging failed Bazel builds

[Sam Gammon]

Hey esteemed Bazel people,

It used to be, that when running `bazel build` with `--verbose_failures` and `--sandbox_debug`, it would drop you into a shell. I'm aware that with the switchover to a new sandbox implementation, this changed and would only print the command that failed.

Now, though, running with Bazel 2.0.0, I don't see any command printed at all, when using the aforementioned flags (either via .bazelrc or manually on the command line).

I know there is a blog post out there (https://blog.bazel.build/2016/03/18/sandbox-easier-debug.html) that is out of date. Just a bump that it should probably be removed, or even better, updated with new procedures for debugging.

I understand code shifts, but what is the procedure now for debugging Bazel builds, or otherwise coaxing it into dumping commands to stdout? I can't seem to find any documentation or follow-up instructions with a new procedure.

[david.o...@gmail.com]

Does --subcommands option help: [1], aka -s?

[1] https://docs.bazel.build/versions/master/user-manual.html#flag--subcommands