Subpar ignores Bazel imports

[calder]

Subpar ignores Bazel py_library imports attributes. This is needed by any workspace with interdependent Python setuptools packages.

The TODO currently references a Buganizer issue: https://github.com/google/subpar/blob/master/subpar.bzl#L62

[calder]

Minimal example

Directory structure

• WORKSPACE
• foo/
  • BUILD
  • foo/
  • __init__.py
  • lib.py
  • main.py

Contents

WORKSPACE:

git_repository(
    name = "subpar",
    remote = "https://github.com/google/subpar",
    tag = "1.0.0",
)

foo/BUILD:

load("@subpar//:subpar.bzl", "par_binary")

py_library(
    name = "foo",
    srcs = ["foo/lib.py"],
    imports = ["."],
)

par_binary(
    name = "foo_main",
    srcs = ["foo/main.py"],
    main = "foo/main.py",
    deps = [
        ":foo",
    ],
)

foo/foo/__init__.py: empty foo/foo/lib.py:

x = 123

• foo/foo/main.py:

  
  from foo.lib import x

print "x = %d" % x

## Result

```sh
➤ bazel run //foo:foo_main.par
.................
INFO: Analysed target //foo:foo_main.par (11 packages loaded).
INFO: Found 1 target...
Target //foo:foo_main.par up-to-date:
  bazel-bin/foo/foo_main.par
INFO: Elapsed time: 3.884s, Critical Path: 0.27s
INFO: Build completed successfully, 15 total actions

INFO: Running command line: bazel-bin/foo/foo_main.par
Traceback (most recent call last):
  File "/usr/lib/python2.7/runpy.py", line 174, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/usr/lib/python2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File ".../.cache/bazel/.../execroot/__main__/bazel-out/local-fastbuild/bin/foo/foo_main.par/__main__.py", line 6, in <module>
ImportError: No module named lib
ERROR: Non-zero return code '1' from command: Process exited with status 1

[duggelz]

Currently blocked on bazel: https://github.com/bazelbuild/bazel/issues/2617

[duggelz]

Actually, in this case, it should work, but my brittle workaround is finding the wrong foo first. I should be able to reorder the heuristic.