Fix examples with Bazel@HEAD

[kotlaja]

This PR fixes multiple errors from the Downstream:

1. Error with catch2 (mentioned in [Bazel CI] ERROR: Analysis of //:catch2_test failed due to missing cc_library load in external dependency #657) - Fix is updating its version.
2. Error with loads in toolchains_llvm - Fix is updating its version.
3. Error with toolchains_protoc (name 'proto_library' is not defined) - Fix is removing toolchains_protoc since it was overriding an incompatible version of toolchain.
4. Error with incompatible_use_toolchain_transition - Seemed to be fixed with upgrade of toolchains_llvm.

Also, updated links for documentation which were not working.

[kotlaja]

Regarding BazelCI error:

ERROR: /var/lib/buildkite-agent/.cache/bazel/_bazel_buildkite-agent/ae0c8c8707a22b569ed3ce7542eb6c9c/external/rules_rust++i+rules_rust_tinyjson/BUILD.bazel:4:37: Compiling Rust (without process_wrapper) rlib tinyjson (4 files) [for tool] failed: Exec failed due to IOException: The file type of '/var/lib/buildkite-agent/.cache/bazel/_bazel_buildkite-agent/ae0c8c8707a22b569ed3ce7542eb6c9c/external/toolchains_llvm++llvm+llvm_toolchain/bin/clang-format' is not supported

I can't reproduce the error, It passes locally for me.
Command I am using is bazel run ... inside rust-examples/02-hello-cross workspace.

[meteorcloudy]

Did you try in gcr.io/bazel-public/ubuntu2204?

[kotlaja]

Didd you try in gcr.io/bazel-public/ubuntu2204?

I tried it now and it still passes, hmm

[gregestren]

As an aside, does anyone know why the CI badge on https://github.com/bazelbuild/examples is red even though the main branch is consistently green?

[gregestren]

As an aside, does anyone know why the CI badge on https://github.com/bazelbuild/examples is red even though the main branch is consistently green?

I guess https://buildkite.com/bazel/bazel-bazel-examples/settings/badges explains it:

• https://badge.buildkite.com/260bbace6a4067a3c60539a31fed1191d341a24cb0bfeb0e23.svg - red
• https://badge.buildkite.com/260bbace6a4067a3c60539a31fed1191d341a24cb0bfeb0e23.svg?branch=main - green

Which is the better signal for this repo?

[kotlaja]

I didn't manage to reproduce the error but I figured out that toolchains_llvm++llvm+llvm_toolchain/bin/clang-format is a symlink that doesn't exist (pointing to nothing). The reason is inside LLVM 19.1.6 - This archive does not contain bin/clang-format, bin/clang-tidy, etc. In other words, when Bazel tries to use or analyze this file (likely as an input to a sandbox), it sees a file type it "doesn't support" (a broken symlink) and fails.

• Could be a "Why it fails with Bazel 9 but not with Bazel 8" question..

Bazel 9 potentially has stricter input validation for action execution?? Could be that some additional validation is added when it prepares the sandbox or inputs for compilation. Then it would encounter this broken symlink and throw an IOException because the file type (broken symlink) is invalid/unsupported in that context.

[meteorcloudy]

Thank you! \o/

[meteorcloudy]

/cc @tjgq probably knows more about the symlink stuff.