[Bug] Infinite Symlink Expansion in external project (new_local_repository)

[firstprayer]

Description of the problem / feature request:

Encountering "Infinite symlink expansion" when integrating an external cmake project which has symlink.

ERROR: infinite symlink expansion detected
[start of symlink chain]
/Users/taiyuanz/Projects/faiss/faiss
/Users/taiyuanz/Projects/faiss
[end of symlink chain]
ERROR: Skipping '@faiss_lib//:faiss_lib': no such package '@faiss_lib//': Infinite symlink expansion
WARNING: Target pattern parsing failed.
ERROR: no such package '@faiss_lib//': Infinite symlink expansion
INFO: Elapsed time: 0.059s
INFO: 0 processes.
FAILED: Build did NOT complete successfully (0 packages loaded)
    Fetching @faiss_lib; Restarting.

I was expecting Bazel to be able to work around this symlink because cmake can handle it pretty well.

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

1. The external project is https://github.com/facebookresearch/faiss. You can do a git clone to have a copy locally. Then you can follow the instruction on INSTALL.md to do ./configure and then make
2. You can see the in the root of the project folder there's a symlink "faiss/ -> ./". This allows the developers of FAISS to write code like "#include <faiss/IndexFlat.h>" etc, even though IndexFlat.h is actually under the root directory
3. To reproduce using bazel, we just need the following simple files:

WORKSPACE

# File //:WORKSPACE
workspace(name = "faiss_server")

# External libraries that don't use bazel.
new_local_repository(
    name = "faiss_lib",
    path = "/Users/taiyuanz/Projects/faiss/",
    build_file_content = """
cc_library(
    name = "faiss_lib",
    srcs = glob(
        ["*.o", "*.h"]
    ),
    visibility = ["//visibility:public"],
)
    """
)

Then you just run

bazel build @faiss_lib//:faiss_lib

Then you will see

ERROR: infinite symlink expansion detected
[start of symlink chain]
/Users/taiyuanz/Projects/faiss/faiss
/Users/taiyuanz/Projects/faiss
[end of symlink chain]
ERROR: Skipping '@faiss_lib//:faiss_lib': no such package '@faiss_lib//': Infinite symlink expansion
WARNING: Target pattern parsing failed.
ERROR: no such package '@faiss_lib//': Infinite symlink expansion
INFO: Elapsed time: 0.059s
INFO: 0 processes.
FAILED: Build did NOT complete successfully (0 packages loaded)
    Fetching @faiss_lib; Restarting.

What operating system are you running Bazel on?

Mac OS X Catalina

What's the output of bazel info release?

release 2.0.0

Have you found anything relevant by searching the web?

I have checked various discussions but haven't found anything similar to this issue.

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

Not yet.

[irengrig]

Hi @firstprayer, the reported problem describes Bazel designed behavior: recursive symlinks are not allowed. Bazel expands symlinks to track file changes for accurate incremental builds.
Similar problem: #2927

[jin]

Closing as WAI and dupe.