Description of the bug:

py_binary rules come with a auto-generated wrapper script which automatically detects runfiles and sets either RUNFILES_DIR or RUNFILES_MANIFEST_FILE, depending on what is found first.

This script has a bug: if progname.runfiles_manifest file is missing, but programe.runfiles/MANIFEST is present, the script erroneously sets RUNFILES_DIR to manifest file location. This causes all sorts of failures down the line (for example when using bazel's runfiles.bash rules)

Code in question:

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

To demonstrate it, we need any bazel repo which uses python runfiles lib. Bazel's own rules_pkg is one example.
First, check out and run the test. It should work:

git clone https://github.com/bazelbuild/rules_pkg.git
cd rules_pkg
bazel run //tests:stamp_test  # This works

Now naively package the runfiles dir and try to use it. Note we've got stamp_test.runfiles/MANIFEST (inside runfiles) but forgot stamp_test.runfiles_manifest:

rm -rf /tmp/work && mkdir /tmp/work && cp -r bazel-bin/tests/stamp_test bazel-bin/tests/stamp_test.runfiles /tmp/work && /tmp/work/stamp_test
...
NotADirectoryError: [Errno 20] Not a directory: '/tmp/work/stamp_test.runfiles/MANIFEST/rules_pkg/tests/stamped_zip.zip'

----------------------------------------------------------------------
Ran 2 tests in 0.002s

FAILED (errors=2)

observe how it treats stamp_test.runfiles/MANIFEST file as a directory and fails.

Which operating system are you running Bazel on?

Various Ubuntu versions (18.04, 20.04, 22.04)

What is the output of bazel info release?

This is present in HEAD and was introduced in 2018. Testcases above were tested on 6.0.0

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 master; git rev-parse HEAD ?

https://github.com/bazelbuild/bazel.git
4427a1fb0cf537da82e1ca4841e0cecda99e1107
4427a1fb0cf537da82e1ca4841e0cecda99e1107

Have you found anything relevant by searching the web?

Nothing. I am guessing very few people use custom bazel packaging scripts that only copy one file but not both.

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

We have a workaround which is to copy both files, and it probably is more correct that way, too. I am reporting this bug for the unlikely case someone else encounters it.

Workarounds for my test case above:

• Include both manifest files:

rm -rf /tmp/work && mkdir /tmp/work && cp -r bazel-bin/tests/stamp_test{,.runfiles,.runfiles_manifest} /tmp/work && /tmp/work/stamp_test
..
OK

• Do not include any manifest files

rm -rf /tmp/work && mkdir /tmp/work && cp -r bazel-bin/tests/stamp_test{,.runfiles} /tmp/work && rm -f /tmp/work/stamp_test.runfiles/MANIFEST && /tmp/work/stamp_test
..
OK