Replace ctx.files.srcs with ctx.attr.srcs in run_binary

[hauserx]

The ctx.files.srcs maybe memory heavy in case of many input sources as it flattens depset, see bazelbuild/bazel#28753

In below reproduction that creates 100k actions, each having 10k inputs this fix allows the used-heap-size-after-gc to drop from 8GB to 300M.

Repo

MODULE.bazel

bazel_dep(name = "bazel_skylib", version = "1.9.0")

myecho

echo "$1" > $2

BUILD.bazel

load("@bazel_skylib//rules:run_binary.bzl", "run_binary")

GENERATED_INPUTS=10000
ACTIONS = 100000

[
    run_binary(
        name="gen_file_" + str(idx),
        args = ["content_gen" + str(idx), "$(location :file_" + str(idx) + ")"],
        tool = ":myecho",
        outs = ["file_" + str(idx)],
    )
    for idx in range(GENERATED_INPUTS)
]

filegroup(
     name="genfiles",
     srcs = ["gen_file_" + str(idx) for idx in range(GENERATED_INPUTS)]
)

[
    run_binary(
        name = "action_" + str(idx),
        args = ["content_action" + str(idx), "$(location :out_" + str(idx) + ")"],
        tool = ":myecho",
        outs = ["out_" + str(idx)],
        srcs = [":genfiles"],
    )
    for idx in range(ACTIONS)
]

run_binary(
    name = "result",
    args = ["content_result", "$(location :final_out)"],
    tool = ":myecho",
    srcs = [":out_" + str(idx) for idx in range(ACTIONS)],
    outs = ["final_out"],
)

Before:

$ USE_BAZEL_VERSION=9.0.0 bazelisk --host_jvm_args=-Xmx64g build :result --nobuild
...
$ USE_BAZEL_VERSION=9.0.0 bazelisk --host_jvm_args=-Xmx64g info used-heap-size-after-gc
8461MB

After:

$ USE_BAZEL_VERSION=9.0.0 bazelisk --host_jvm_args=-Xmx64g info used-heap-size-after-gc
305MB