Fix dependency resolution when generating rules.

[while-false]

From somewhere over the rainbow we had a proposal for code like this:

COMMON_DEPS = [ # Please find a better name!
        "@com_google_protobuf//:any_proto",
        "@com_google_protobuf//:duration_proto",
]

proto_library(
	name = "foo",
	deps = COMMON_DEPS,
)

cc_eventuals_library(
    name = "object_store_eventuals_generated",
    visibility = ["//visibility:public"],
    deps = [
        ":foo",
    ] + COMMON_DEPS,
)

The rule generation should be able to deduce the common dependencies automagically based on the foo dependencies.

[CodingCanuck]

I think the COMMON_DEPS approach is an anti-pattern. From https://bazel.build/rules/build-style#dependencies :

Prefer to list dependencies directly, as a single list. Putting the "common" dependencies of several targets into a variable reduces maintainability, makes it impossible for tools to change the dependencies of a target, and can lead to unused dependencies.

Specifically, if you have this:

COMMON_DEPS [
	"//used_by_all",
	# Automated tools can't / won't safely remove this!
	"//used_by_none_aka_unnecessary_dep",
]

# Only needs //used_by_all
proto_library(
	name = "foo",
	deps = COMMON_DEPS,
)

# Only needs //used_by_all
cc_generated_library(
    name = "foo_generated",
    visibility = ["//visibility:public"],
    deps = [
        ":foo",
    ] + COMMON_DEPS,
)

Then automated cleanup tools can't remove the unused dep in the common list.

Should we close this?