touch WORKSPACE

cat <<EOF > BUILD.bazel
load(":rules.bzl", "build_setting", "library_no_transition", "library_input_outdir", "library_input_outdir_bs1")
load(":setup_graph.bzl", "setup_graph")

build_setting(
    name = "bs1",
    build_setting_default = "bs1_default",
)

[
    setup_graph(case=case, rule=rule, rule_args=rule_args)

    for case, rule, rule_args in [
        ("1", library_no_transition, {}),
        ("2", library_input_outdir, {
            "input_settings": {
                "//command_line_option:output directory name": "any",
            }},
        ),
        ("3", library_input_outdir_bs1, {
            "input_settings": {
                "//command_line_option:output directory name": "any",
                "//:bs1": "bs1_default",
            }},
        ),
    ]
]
EOF

cat <<EOF > setup_graph.bzl
load(":rules.bzl", "no_transition", "input_bs1", "library_input_bs1")

def setup_graph(*, case, rule, rule_args):
    no_transition(
        name = "A" + case,
        deps = [":B" + case, ":C" + case],
    )

    input_bs1(
        name = "B" + case,
        deps = [":D" + case],
        input_settings = {"//:bs1": "bs1_B"},
    )

    input_bs1(
        name = "C" + case,
        deps = [":D" + case],
        input_settings = {"//:bs1": "bs1_C"},
    )

    rule(
        name = "D" + case,
        deps = [":E" + case],
        **rule_args
    )

    library_input_bs1(
        name = "E" + case,
        path_resolution = ["//:bs1"],
    )
EOF

cat <<EOF > rules.bzl
load("@bazel_tools//tools/cpp:toolchain_utils.bzl", "find_cpp_toolchain")

BuildSettingInfo = provider(fields = ["value"])

def _build_setting_impl(ctx):
    return BuildSettingInfo(value = ctx.build_setting_value)

def _dummy_rule_impl(ctx, files = []):
    transitive = [dep[DefaultInfo].files for dep in ctx.attr.deps]
    return [DefaultInfo(files = depset(direct = files, transitive = transitive))]

def _library_rule_impl(ctx):
    path_resolution = "".join(["_%s" % dep[BuildSettingInfo].value for dep in ctx.attr.path_resolution])
    name = ctx.label.name + path_resolution
    src = ctx.actions.declare_file(name + ".c")
    ctx.actions.write(src, "int %s() {return 1;}\n" % name)
    cc_toolchain = find_cpp_toolchain(ctx)
    feature_configuration = cc_common.configure_features(ctx = ctx, cc_toolchain = cc_toolchain)
    cc_args = {"actions": ctx.actions, "feature_configuration": feature_configuration, "cc_toolchain": cc_toolchain}
    compilation_context, compilation_outputs = cc_common.compile(
        name = name, srcs = [src], **cc_args)
    linking_context, linking_outputs = cc_common.create_linking_context_from_compilation_outputs(
        name = name, compilation_outputs = compilation_outputs, **cc_args)
    library_to_link = linking_outputs.library_to_link
    files = []
    files += [library_to_link.static_library] if library_to_link.static_library else []
    files += [library_to_link.pic_static_library] if library_to_link.pic_static_library else []
    return _dummy_rule_impl(ctx, files = files) + [CcInfo(
        compilation_context = compilation_context, linking_context = linking_context)]

def _input_transition_impl(settings, attr):
    settings = {setting: settings[setting] for setting in attr._input_settings}
    settings.update(attr.input_settings)
    return settings

def _create_custom_rule(implementation, input = [], cpp = False):
    attrs = {"deps": attr.label_list(), "path_resolution": attr.label_list()}
    args = {"attrs": attrs, "implementation": implementation}
    if cpp:
        args["fragments"] = ["cpp"]
        args["toolchains"] = ["@bazel_tools//tools/cpp:toolchain_type"]
        attrs["_cc_toolchain"] = attr.label(default = "@bazel_tools//tools/cpp:current_cc_toolchain")

    if input:
        attrs.update({
            "input_settings": attr.string_dict(),
            "_input_settings": attr.string_list(default = input),
            "_whitelist_function_transition": attr.label(
                default = "@bazel_tools//tools/whitelists/function_transition_whitelist"),
        })
        args["cfg"] = transition(inputs = input, outputs = input, implementation = _input_transition_impl)
    return rule(**args)

build_setting = rule(
    implementation = _build_setting_impl,
    build_setting = config.string(flag = False),
)

outdir = "//command_line_option:output directory name"
no_transition = _create_custom_rule(_dummy_rule_impl)
input_bs1 = _create_custom_rule(_dummy_rule_impl, ["//:bs1"])
library_no_transition = _create_custom_rule(_library_rule_impl, cpp = True)
library_input_bs1 = _create_custom_rule(_library_rule_impl, ["//:bs1"], cpp = True)
library_input_outdir = _create_custom_rule(_library_rule_impl, [outdir], cpp = True)
library_input_outdir_bs1 = _create_custom_rule(_library_rule_impl, [outdir, "//:bs1"], cpp = True)
EOF