oci_load drops empty strings in cmd list

[garrettjohnston]

The oci_load rule seems to drop empty strings from the cmd list. This doesn't happen with rules_docker container_image rule.

The empty string behavior is useful for Java libraries like JCommander that help parse command line args.

To reproduce

WORKSPACE

oci_pull(
    name = "distroless_java21",
    digest = "sha256:ed5be62a70c5b99708b4ad0fc53bda628d11e46e917f66720fd218cae8fe1568",
    image = "gcr.io/distroless/java21-debian12",
)

BUILD

load("@rules_oci//oci:defs.bzl", "oci_image", "oci_load")

oci_image(
    name = "test_image",
    base = "@distroless_java21",
    cmd = [
        "hello",
        "",
        "goodbye",
        "",
    ],
)

oci_load(
    name = "test_image_load",
    image = ":test_image",
    repo_tags = [
        "test_image:latest",
    ],
)

$ bazel run :test_image_load
$ docker inspect test_image:latest
...
 "Config": {
            "Cmd": [
                "hello",
                "goodbye"
            ],
            "Entrypoint": [
                "/usr/bin/java",
                "-jar"
            ],
...

Notice the empty strings are missing in the CMD list.

• rules_oci v2.2.6
• Bazel version 6.5.0
• Docker version 28.4.0, build d8eb465