Comment by rhencke

Here's what I mean:

    genrule(name = "oops", cmd = "date > $@", outs = ["oops.txt"])

This is admittedly contrived, but sadly not unrealistic.

Again, I am not picking on Bazel here. Correct builds are difficult enough to get right even when everyone involved wants to keep the build correct! But, the reality is that a lot of real-world build conditions can be downright hostile. (did you know that ext4 vs xfs can change the order JARs in the same directory are loaded off the classpath? I wish I didn't!)