Crash when using subrules in aspects that uses to a bool_flag

[jacky8hyf]

Description of the bug:

Bazel crashes when using subrules in aspects that uses to a bool_flag

Which category does this issue belong to?

Configurability, Rules API

What's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

# a.bzl
def _print_label_impl(subrule_ctx, *, _should_print):
    pass

_print_label = subrule(
    implementation = _print_label_impl,
    attrs = {
        "_should_print": attr.label(default = "//:debug_print_label"),
    },
)

def _print_label_aspect_impl(_target, _ctx):
    _print_label()
    return []

_print_label_aspect = aspect(
    implementation = _print_label_aspect_impl,
    subrules = [_print_label],
)

def _myrule_impl(ctx):
    return DefaultInfo(files = depset(ctx.files.src))

myrule = rule(
    implementation = _myrule_impl,
    attrs = {
        "src": attr.label(
            allow_files = True,
            aspects = [_print_label_aspect],
        ),
    },
)

# BUILD.bazel
load("@bazel_skylib//rules:common_settings.bzl", "bool_flag")
load(":a.bzl", "myrule")

bool_flag(
    name = "debug_print_label",
    build_setting_default = False,
    visibility = ["//build/kernel:__subpackages__"],
)

filegroup(
    name = "file",
    srcs = ["a.bzl"]
)

myrule(
    name = "ok",
    src = ":file"
)

and an empty MODULE.bazel file.

Then

$ bazel build //:ok  --experimental_rule_extension_api --//:debug_print_label
Starting local Bazel server and connecting to it...
Analyzing: target //:ok (1 packages loaded, 0 targets configured)
    currently loading: @@bazel_tools//tools
[0 / 1] checking cached actions
FATAL: bazel crashed due to an internal error. Printing stack trace:
java.lang.RuntimeException: Unrecoverable error while evaluating node '//:file#//:a.bzl%_print_label_aspect ConfiguredTargetKey{label=//:file, config=BuildConfigurationKey[4cc7959eb23e0d30c542520c40bc7e2d5c65d1105b5d1458ef83c5b1bb5b10ae]} {}' (requested by nodes 'ConfiguredTargetKey{label=//:ok, config=BuildConfigurationKey[4cc7959eb23e0d30c542520c40bc7e2d5c65d1105b5d1458ef83c5b1bb5b10ae]}')
	at com.google.devtools.build.skyframe.AbstractParallelEvaluator$Evaluate.run(AbstractParallelEvaluator.java:550)
	at com.google.devtools.build.lib.concurrent.AbstractQueueVisitor$WrappedRunnable.run(AbstractQueueVisitor.java:414)
	at java.base/java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinPool.scan(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source)
Caused by: net.starlark.java.eval.Starlark$UncheckedEvalException: NullPointerException thrown during Starlark evaluation (//:file)
	at <starlark>._print_label(<builtin>:0)
	at <starlark>._print_label_aspect_impl(/mnt/sdc/android/tmpdir2/a.bzl:12)
Caused by: java.lang.NullPointerException: Attribute $//:a.bzl%_print_label%_should_print does not exist
	at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:1010)
	at com.google.devtools.build.lib.packages.RuleClass.getAttributeByName(RuleClass.java:2055)
	at com.google.devtools.build.lib.analysis.starlark.StarlarkSubrule.call(StarlarkSubrule.java:143)
	at net.starlark.java.eval.StarlarkCallable.fastcall(StarlarkCallable.java:86)
	at net.starlark.java.eval.Starlark.fastcall(Starlark.java:806)
	at net.starlark.java.eval.Eval.evalCall(Eval.java:682)
	at net.starlark.java.eval.Eval.eval(Eval.java:497)
	at net.starlark.java.eval.Eval.exec(Eval.java:271)
	at net.starlark.java.eval.Eval.execStatements(Eval.java:82)
	at net.starlark.java.eval.Eval.execFunctionBody(Eval.java:66)
	at net.starlark.java.eval.StarlarkFunction.fastcall(StarlarkFunction.java:179)
	at net.starlark.java.eval.Starlark.fastcall(Starlark.java:806)
	at com.google.devtools.build.lib.skyframe.StarlarkAspectFactory.create(StarlarkAspectFactory.java:64)
	at com.google.devtools.build.lib.analysis.ConfiguredTargetFactory.createAspect(ConfiguredTargetFactory.java:611)
	at com.google.devtools.build.lib.skyframe.AspectFunction.createAspect(AspectFunction.java:778)
	at com.google.devtools.build.lib.skyframe.AspectFunction.compute(AspectFunction.java:366)
	at com.google.devtools.build.skyframe.AbstractParallelEvaluator$Evaluate.run(AbstractParallelEvaluator.java:461)
	at com.google.devtools.build.lib.concurrent.AbstractQueueVisitor$WrappedRunnable.run(AbstractQueueVisitor.java:414)
	at java.base/java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinPool.scan(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source)

Which operating system are you running Bazel on?

Linux

What is the output of bazel info release?

release 7.3.0

If bazel info release returns development version or (@non-git), tell us how you built Bazel.

No response

What's the output of git remote get-url origin; git rev-parse HEAD ?

No response

If this is a regression, please try to identify the Bazel commit where the bug was introduced with bazelisk --bisect.

No response

Have you found anything relevant by searching the web?

No response

Any other information, logs, or outputs that you want to share?

This only happens when using subrules. If I put the attrs in the aspect directly, then it would work properly.

def _print_label_aspect_impl(_target, _ctx):
    return []

_print_label_aspect = aspect(
    implementation = _print_label_aspect_impl,
    attrs = {
        "_should_print": attr.label(default = "//:debug_print_label"),
    },
)

def _myrule_impl(ctx):
    return DefaultInfo(files = depset(ctx.files.src))

myrule = rule(
    implementation = _myrule_impl,
    attrs = {
        "src": attr.label(
            allow_files = True,
            aspects = [_print_label_aspect],
        ),
    },
)

[hvadehra]

@bazel-io flag

[iancha1992]

@bazel-io fork 7.4.0

[iancha1992]

A fix for this issue has been included in Bazel 7.4.0 RC1. Please test out the release candidate and report any issues as soon as possible.
If you're using Bazelisk, you can point to the latest RC by setting USE_BAZEL_VERSION=7.4.0rc1. Thanks!