bazel pypi macro self-edge - pypi

Question

I'm stumbling around trying to get bazel working with pypi dependencies.
./pypi.bzl:
def _impl(ctx):
ctx.actions.run_shell(
command = "pip download %s" % ctx.package
)
_pypi_package = rule(
implementation=_impl,
attrs={"package": attr.label(mandatory=True)},
)
def pypi_package(package):
_pypi_package(name = package, package = package)
./BUILD:
py_binary(
name = "app",
srcs = ["app.py"],
deps = [":python-dateutil"]
)
load("//:pypi.bzl", "pypi_package")
pypi_package(
package="python-dateutil",
)
Trying to build:
$ bazel build app
ERROR: /path/to/cwd/BUILD:9:1: in _pypi_package rule //:python-dateutil: cycle in dependency graph:
//:app
.-> //:python-dateutil [self-edge]
`--
This cycle occurred because of a configuration option.
ERROR: Analysis of target '//:app' failed; build aborted.
INFO: Elapsed time: 0.219s
No idea if this is even the right approach for working with external dependencies, but ignoring that, I don't understand where the self-dep here is coming from. In fact, I don't see that I'm declaring any deps for the pypi_package rule at all. What's going on?

Answer 1

The issue was attr.label: "label" here means BUILD label. I should have been using attr.string.