py_runtime does not consume root_symlinks from the interpreter attr (hermetic toolchain)

[wade-arista]

🐞 bug report

Affected Rule

py_runtime is affected.

For example

py_runtime(
    name = "hermetic_runtime",
    files = ["extracted_toolchain"],
    interpreter = "extracted_toolchain",
    interpreter_version_info = {
        "major": "3",
        "minor": "9",
        "micro": "21",
    },
    python_version = "PY3",
    visibility = ["//BazArTest/py_toolchain:__pkg__"],
)

Is this a regression?

No. It was discovered when upgrading to bazel 9.0.0, however, because @bazel_tools//tools/bash/runfiles is now an alias that uses root_symlinks.

Description

The py_runtime interpreter from the example makes use of runfiles.bash, but if it is only present in the Runfiles.root_symlinks of interpreter / files, then it does not exist in the runfiles directory when executing python actions.

You can see here:

rules_python/python/private/py_runtime_rule.bzl

Lines 54 to 58 in 393dcfd

	runtime_files = depset(transitive = [
	interpreter_di.files,
	interpreter_di.default_runfiles.files,
	runtime_files,
	])

that it does not consider the root_symlinks in the interpreter runfiles.

🔬 Minimal Reproduction

It is pretty involved, so I'm hoping the description makes the issue readily apparent. I can work on a reproducer if that is not the case.

🌍 Your Environment

Operating System:

  
AlmaLinux 9.7 (Moss Jungle Cat)
  

Output of bazel version:

  
Bazelisk version: v1.26.0
INFO: Invocation ID: decd4a2d-e400-43ca-8558-5e818e7da8d1
Build label: 9.0.0
Build target: @@//src/main/java/com/google/devtools/build/lib/bazel:BazelServer
Build time: Tue Jan 20 18:16:47 2026 (1768933007)
Build timestamp: 1768933007
Build timestamp as int: 1768933007
  

Rules_python version:

  
bazel_dep(name = "rules_python", version = "1.7.0")