chore(bzlmod): add trivial pass-through module extension for oci_pull

[alexeagle]

However it trips over the labels in our generated build files making assumptions about repository names, needs some fixing

[alexeagle]

I made an example to test this, and there's a bug. Problem here is

ERROR: /home/alexeagle/Projects/bazel-examples/oci_go_image/BUILD.bazel:34:10:
no such target '@rules_oci~override~oci~distroless_base//:distroless_base': target 'distroless_base' not declared in package '' 
defined by /shared/cache/bazel/user_base/359b45a24cf55cc22380e941fe3bcf54/external/rules_oci~override~oci~distroless_base/BUILD.bazel

which is caused by https://github.com/bazel-contrib/rules_oci/blob/main/oci/pull.bzl#L246

I wanted to have nice syntax sugar for users to choose a base image like just base = "@distroless_static" but one option here is to give that up and require a label like @distroless_static//:image - then we don't need to know the repo name here to create a target with a matching name.

[kormide]

I made an example to test this, and there's a bug. Problem here is

ERROR: /home/alexeagle/Projects/bazel-examples/oci_go_image/BUILD.bazel:34:10:
no such target '@rules_oci~override~oci~distroless_base//:distroless_base': target 'distroless_base' not declared in package '' 
defined by /shared/cache/bazel/user_base/359b45a24cf55cc22380e941fe3bcf54/external/rules_oci~override~oci~distroless_base/BUILD.bazel

which is caused by https://github.com/bazel-contrib/rules_oci/blob/main/oci/pull.bzl#L246

I wanted to have nice syntax sugar for users to choose a base image like just base = "@distroless_static" but one option here is to give that up and require a label like @distroless_static//:image - then we don't need to know the repo name here to create a target with a matching name.

I'm missing some pieces here. So you want to be able to pass in base = "@distroless_static" into oci_image? As in you want to pass a string rather than a label and have it do the equivalent of appending the //:image target?

[alexeagle]

@distroless_static is a label! It expands to @distroless_static//:distroless_static after the de-sugaring.

[alexeagle]

okay the downstream example is green now!