Add note about rules_foreign_cc when using @cargo_raze//:raze.

[PiotrSikora]

Signed-off-by: Piotr Sikora piotrsikora@google.com

[PiotrSikora]

cc @UebelAndre

[UebelAndre]

This is not accurate. The macros are loading rules_foreign_cc. Did you find this to not be the case?

[PiotrSikora]

This is not accurate. The macros are loading rules_foreign_cc. Did you find this to not be the case?

I found this not to be the case. I'm adding support for running @cargo_raze//:raze in the Proxy-Wasm Rust SDK repo in proxy-wasm/proxy-wasm-rust-sdk#88. You can check it out to verify:

$ git clone https://github.com/PiotrSikora/proxy-wasm-rust-sdk -b cargo-raze_v0.11.0 /tmp/raze
$ cd /tmp/raze

Right now, it includes http_archive(rules_foreign_cc) in bazel/repositories.bzl and it works fine:

$ bazel --noworkspace_rc run @cargo_raze//:raze -- --manifest-path=$(pwd)/Cargo.toml
WARNING: The following rc files are no longer being read, please transfer their contents or import their path into one of the standard rc files:
/tmp/raze/.bazelrc
Starting local Bazel server and connecting to it...
INFO: Invocation ID: d770fc81-2664-4888-bf33-9a8863100331
INFO: SHA256 (https://mirror.bazel.build/ftp.pcre.org/pub/pcre/pcre-8.43.tar.gz) = 0b8e7465dc5e98c757cc3650a20a7843ee4c3edf50aaf60bb33fd879690d2c73
DEBUG: Rule 'cargo_raze__pcre' indicated that a canonical reproducible form can be obtained by modifying arguments sha256 = "0b8e7465dc5e98c757cc3650a20a7843ee4c3edf50aaf60bb33fd879690d2c73"
DEBUG: Repository cargo_raze__pcre instantiated at:
  /tmp/raze/WORKSPACE:13:44: in <toplevel> /home/piotrsikora/.cache/bazel/_bazel_piotrsikora/29e3b7276a8bbe7fc5a302b857cd333d/external/proxy_wasm_rust_sdk/bazel/dependencies.bzl:27:28: in proxy_wasm_rust_sdk_cargo_raze_dependencies
/home/piotrsikora/.cache/bazel/_bazel_piotrsikora/29e3b7276a8bbe7fc5a302b857cd333d/external/cargo_raze/repositories.bzl:41:22: in cargo_raze_repositories
/home/piotrsikora/.cache/bazel/_bazel_piotrsikora/29e3b7276a8bbe7fc5a302b857cd333d/external/cargo_raze/third_party/pcre/pcre_repositories.bzl:7:10: in pcre_repositories
/home/piotrsikora/.cache/bazel/_bazel_piotrsikora/29e3b7276a8bbe7fc5a302b857cd333d/external/bazel_tools/tools/build_defs/repo/utils.bzl:201:18: in maybe
Repository rule http_archive defined at:
/home/piotrsikora/.cache/bazel/_bazel_piotrsikora/29e3b7276a8bbe7fc5a302b857cd333d/external/bazel_tools/tools/build_defs/repo/http.bzl:336:31: in <toplevel>
INFO: Analyzed target @cargo_raze//:raze (206 packages loaded, 15993 targets configured).
INFO: Found 1 target...
Target @cargo_raze//impl:cargo_raze_bin up-to-date:
  bazel-bin/external/cargo_raze/impl/cargo_raze_bin
INFO: Elapsed time: 46.023s, Critical Path: 12.31s
INFO: 342 processes: 263 remote cache hit, 79 internal.
INFO: Build completed successfully, 342 total actions
INFO: Build completed successfully, 342 total actions

But when you remove http_archive(rules_foreign_cc) from bazel/repositories.bzl and its workspace definitions from bazel/dependencies.bzl, then it fails:

$ bazel --noworkspace_rc run @cargo_raze//:raze -- --manifest-path=$(pwd)/Cargo.toml
WARNING: The following rc files are no longer being read, please transfer their contents or import their path into one of the standard rc files:
/home/piotrsikora/Google/proxy-wasm-rust-sdk/.bazelrc
INFO: Invocation ID: f23b6f18-524c-48a3-b345-ab498013727d
ERROR: Failed to load Starlark extension '@rules_foreign_cc//:workspace_definitions.bzl'.
Cycle in the workspace file detected. This indicates that a repository is used prior to being defined.
The following chain of repository dependencies lead to the missing definition.
 - @rules_foreign_cc
This could either mean you have to add the '@rules_foreign_cc' repository with a statement like `http_archive` in your WORKSPACE file (note that transitive dependencies are not added automatically), or move an existing definition earlier in your WORKSPACE file.
ERROR: cycles detected during target parsing
INFO: Elapsed time: 1.919s
INFO: 0 processes.
FAILED: Build did NOT complete successfully (0 packages loaded)
FAILED: Build did NOT complete successfully (0 packages loaded)

[UebelAndre]

That's because you're loading cargo_raze_transitive_deps in the same .bzl where yrules_foreign_cc is being defined (via cargo_raze_repositories).

[UebelAndre]

If you move the load for the transitive deps into a second file. You should be able to resolve your issue. But as it's written in the README.md, the comment is incorrect since that will work if you add it to a WORKSPACE file

[PiotrSikora]

If you move the load for the transitive deps into a second file. You should be able to resolve your issue.

Unless I'm mistaken, that would require a third file (repositories.bzl to load @cargo_raze, dependencies.bzl to call cargo_raze_repositories() and a new file to call cargo_raze_transitive_deps()), which isn't pretty.

But as it's written in the README.md, the comment is incorrect since that will work if you add it to a WORKSPACE file

That's a fair point, although most "real world" projects (at least, those that I interact with) don't clutter WORKSPACE too much.

Also, why don't we import rules_rust via macros as well? It seems to work fine, see: #396.