Create headers for a target

materialize_headers_aspect.bzl

def _impl(target, ctx):
    deps = [target]
    if hasattr(ctx.rule.attr, "elf"):
        deps.append(ctx.rule.attr.elf)
    if hasattr(ctx.rule.attr, "srcs"):
        deps.extend(ctx.rule.attr.srcs)
    if hasattr(ctx.rule.attr, "deps"):
        deps.extend(ctx.rule.attr.deps)

    all_header_files = []
    for dep in deps:
        if CcInfo in dep:
            all_header_files.append(dep[CcInfo].compilation_context.headers)
        if OutputGroupInfo in dep and hasattr(dep[OutputGroupInfo], "header_files"):
            all_header_files.append(dep[OutputGroupInfo].header_files)

    return [
        OutputGroupInfo(
            header_files = depset(
                transitive = all_header_files
            ),
        ),
    ]

materialize_headers = aspect(
    attr_aspects = ["srcs", "deps", "elf"],
    implementation = _impl,
    apply_to_generating_rules = True,
)