bazel_external_repository_test: ModuleNotFoundError: No module named 'six'

[ehrtro]

Description of the problem / feature request:

When running bazel_external_repository_test we're encountering the following issue:
fastbuild/bin/src/test/py/bazel/bazel_external_repository_test.runfiles/io_bazel/src/test/py/bazel/bazel_external_repository_test.py", line 19, in <module> from six.moves import SimpleHTTPServer ModuleNotFoundError: No module named 'six'

.. where the failing line in the tests looks like this: from six.moves import SimpleHTTPServer

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

Reproducing this issue is fairly hard since we're not 100% sure about what's causing this issue in our specific environment.

What operating system are you running Bazel on?

Red Hat Enterprise Linux 7 (RHEL7)

Have you found anything relevant by searching the web?

No

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

When looking in the relevant BUILD-file we find that the BUILD initially looks like:

py_test( name = "bazel_external_repository_test", size = "medium", srcs = ["bazel_external_repository_test.py"], data = glob(["testdata/bazel_external_repository_test/**"]), tags = [ "requires-network", ], deps = [ ":test_base" ], )

Which results in the issue stated as above.

But by adding: //third_party/py/six in the list of dependencies, resulting in
py_test( name = "bazel_external_repository_test", size = "medium", srcs = ["bazel_external_repository_test.py"], data = glob(["testdata/bazel_external_repository_test/**"]), tags = [ "requires-network", ], deps = [ ":test_base", "//third_party/py/six", ], )

This issue is fixed and no more issues are envoked when running the test.

So now to the question: We do not understand how this test can pass in the orignial Bazel repo without this dependency added to the list. We're still not sure if this might is to be seen as a bug in the system, or if it is something related to our own environment? Thoughts on this?

[meisterT]

cc @brandjon

[ehrtro]

@meisterT , @brandjon

Any further progress on this issue? It seems like #11664 would solve this issue without breaking something else.

[meisterT]

cc @meteorcloudy
Yun, do you have any idea whether we do anything special with this test on the Bazel CI images?

[meteorcloudy]

I guess it's because six is pre-installed in the docker we run on CI for bazel test?
https://github.com/bazelbuild/continuous-integration/blob/4d2a7dab6c4767e741683c5e68fc5b737a7b9805/buildkite/docker/ubuntu1804/Dockerfile#L40

[jtillwickEA]

Still no fix for this.