bzlmod sysroot example test not working

[steve-261370]

I cloned the repo and went into the tests directory.

The following command, which uses the llvm sysroot toolchain, with bzlmod disabled, works:

bazel test --enable_bzlmod=false --extra_toolchains=@llvm_toolchain_with_sysroot//:cc-toolchain-x86_64-linux //:all

But when bzlmod is enabled, the build fails

bazel test --enable_bzlmod=true --extra_toolchains=@llvm_toolchain_with_sysroot//:cc-toolchain-x86_64-linux //:all

The error returned is:

ERROR: An error occurred during the fetch of repository 'toolchains_llvm~override~llvm~llvm_toolchain_with_sysroot': Traceback (most recent call last): File "/home/steve-261370/.cache/bazel/_bazel_steve-261370/fe79d53e53f1045ef52b7f75d9f074d8/external/toolchains_llvm~override/toolchain/internal/configure.bzl", line 87, column 57, in llvm_config_impl llvm_dist_path_prefix = _pkg_path_from_label(llvm_dist_label) File "/home/steve-261370/.cache/bazel/_bazel_steve-261370/fe79d53e53f1045ef52b7f75d9f074d8/external/toolchains_llvm~override/toolchain/internal/common.bzl", line 144, column 13, in pkg_path_from_label if label.workspace_root: Error: 'workspace_root' is not allowed on invalid Label @[unknown repo 'llvm_toolchain_llvm' requested from @toolchains_llvm~override]//:BUILD.bazel

It looks like the github tests only run through the sysroot tests with bzlmod=false. I am running bazel 6.4.0 on a debian-based system.

[patrice332]

Hitting the same issue

[fmeum]

We are also hitting this. For now, you can work around this by specifying a canonical label:

llvm = use_extension("@toolchains_llvm//toolchain/extensions:llvm.bzl", "llvm")
llvm.toolchain(
    llvm_version = "16.0.4",
    sysroot = {
        # The extension doesn't handle labels to external repositories correctly: It does not map
        # apparent names such as @org_chromium_sysroot_linux_x64 to the correct Bazel-internal
        # canonical repository name. As a workaround, specify the canonical name directly.
        # TODO: Get rid on this dependency of Bazel implementation details when toolchains_llvm
        #       offers an attribute of type label rather than string.
        "linux-x86_64": "@@_main~_repo_rules~org_chromium_sysroot_linux_x64//:sysroot",
    },
)
use_repo(llvm, "llvm_toolchain")

[mering]

How can I find out the canonical label of a transitive non-module dependency (made visible via use_repo())?

[fmeum]

You can bazel query --canonical_labels for it using a regular label.

[mering]

You can bazel query --canonical_labels for it using a regular label.

Thanks for the hint. I got it working by using --consistent_labels.

[Lev1ty]

the full command bazel query --consistent_labels @org_chromium_sysroot_linux_x64//:sysroot

the below snippet worked well for me

bazel_dep(name = "toolchains_llvm", version = "0.10.3")

http_archive = use_repo_rule("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
  name = "org_chromium_sysroot_linux_x64",
  integrity = "sha256-G+YOfEVqvFkKYTxk+rTqx2MsgexvInNKYbU2aaRAc0Y=",
  urls = ["https://commondatastorage.googleapis.com/chrome-linux-sysroot/toolchain/2028cdaf24259d23adcff95393b8cc4f0eef714b/debian_bullseye_amd64_sysroot.tar.xz"],
  build_file_content = """
filegroup(
  name = "sysroot",
  srcs = glob(["*/**"]),
  visibility = ["//visibility:public"],
)
""",
)

llvm = use_extension("@toolchains_llvm//toolchain/extensions:llvm.bzl", "llvm")
LLVM_VERSION = "16.0.4"
llvm.toolchain(llvm_version = LLVM_VERSION)
use_repo(llvm, "llvm_toolchain", "llvm_toolchain_llvm")
llvm.toolchain(
  name = "llvm_toolchain_with_sysroot",
  llvm_version = LLVM_VERSION,
  # https://github.com/bazel-contrib/toolchains_llvm/issues/234
  # aspect query --consistent_labels @org_chromium_sysroot_linux_x64//:sysroot
  sysroot = {"linux-x86_64": "@@_main~_repo_rules~org_chromium_sysroot_linux_x64//:sysroot"},
  toolchain_roots = {"": "@@toolchains_llvm~~llvm~llvm_toolchain_llvm//"},
)
use_repo(llvm, "llvm_toolchain_with_sysroot")
register_toolchains("@llvm_toolchain//:all")