Tolerating individual dep-builder failures is deliberate: some packages are el-
or arch-pinned and are expected to fail on some targets. Tolerating all of them
is not -- it means the builder is unusable, the invocation produced nothing, and
whatever the run publishes came from somewhere other than this build.
Count the failures on both the serial and the parallel path and stop when they
account for every attempted step, before collection can take an earlier run's
artifacts for this one's. The rule itself lives in BuildUtils, where it can be
exercised without a builder.
Vinícius Ferrão