bazel: --distinct_host_configuration=false causes conflicting actions on bazel test --test_arg

Description of the problem:

Enabling --distinct_host_configuration=false causes tests to fail to build when --test_arg is set. Specifically, a bazel test --test_arg=... following a bazel test without --test_arg set fails in this manner. The test succeeds if both commands do not set --test_arg or if both set the same --test_arg.

Bugs: what’s the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

Make sure to have bazelisk installed and run the following script in an empty directory.

echo USE_BAZEL_VERSION=5.0.0 >.bazeliskrc
touch WORKSPACE
cat >BUILD.bazel <<EOF
sh_test(
    name = "test",
    srcs = ["test.sh"],
)
EOF
touch test.sh
chmod +x test.sh
cat >.bazelrc <<EOF
test --nocache_test_results
EOF

echo SUCCEEDS
bazel test //:test; bazel test //:test --test_arg=foo

cat >>.bazelrc <<EOF
build --distinct_host_configuration=false
EOF

echo FAILS
bazel test //:test; bazel test //:test --test_arg=foo

Note, this seems to be a regression. Using Bazel version 4.2.2 instead of 5.0.0 does not trigger this issue.

What operating system are you running Bazel on?

Ubuntu 21.04

What’s the output of bazel info release?

release 5.0.0

Any other information, logs, or outputs that you want to share?

This issue was discovered here and then stripped down to a minimal repro.