Support for --incompatible_use_plus_in_repo_names

[criemen]

Bazel 7.3.0 introduced --incompatible_use_plus_in_repo_names which changes the bzlmod separator from ~ to + (for performance reasons on Windows). This flag will be flipped with 8.0.0.
Flipping that flag currently is incompatible with rules_rust, as (at least) the crate_universe code assumes that the separator is ~.
Im getting

ERROR: Traceback (most recent call last):
        File "/private/var/tmp/_bazel_criemen/267ec2c545f0139b2caed9502387afe1/external/rules_rust+/crate_universe/extension.bzl", line 369, column 37, in _crate_impl
                _generate_hub_and_spokes(module_ctx, cargo_bazel, cfg, annotations, cargo_lockfile = cargo_lockfile, manifests = manifests)
        File "/private/var/tmp/_bazel_criemen/267ec2c545f0139b2caed9502387afe1/external/rules_rust+/crate_universe/extension.bzl", line 132, column 16, in _generate_hub_and_spokes
                cargo_bazel(splice_args)
        File "/private/var/tmp/_bazel_criemen/267ec2c545f0139b2caed9502387afe1/external/rules_rust+/crate_universe/private/module_extensions/cargo_bazel_bootstrap.bzl", line 66, column 17, in run
                fail("%s returned with exit code %d:\n%s" % (pretty_args, result.return_code, result.stderr))
Error in fail: /private/var/tmp/_bazel_criemen/267ec2c545f0139b2caed9502387afe1/modextwd/rules_rust++_crate+ql++r/cargo-bazel splice --output-dir /private/var/tmp/_bazel_criemen/267ec2c545f0139b2caed9502387afe1/modextwd/rules_rust++_crate+ql++r/rd/splicing-output --config /private/var/tmp/_bazel_criemen/267ec2c545f0139b2caed9502387afe1/modextwd/rules_rust++_crate+ql++r/rd/config.json --splicing-manifest /private/var/tmp/_bazel_criemen/267ec2c545f0139b2caed9502387afe1/modextwd/rules_rust++_crate+ql++r/rd/splicing_manifest.json --cargo-lockfile /private/var/tmp/_bazel_criemen/267ec2c545f0139b2caed9502387afe1/external/ql+/ruby/extractor/Cargo.lock --cargo /private/var/tmp/_bazel_criemen/267ec2c545f0139b2caed9502387afe1/external/rules_rust++rust_host_tools+rust_host_tools/bin/cargo --rustc /private/var/tmp/_bazel_criemen/267ec2c545f0139b2caed9502387afe1/external/rules_rust++rust_host_tools+rust_host_tools/bin/rustc returned with exit code 1:
Error: Failed to parse splicing manifest

Caused by:
    0: Failed to load SplicingManifest
    1: Invalid Label: @@ql+//ruby/extractor:Cargo.toml at line 5 column 149
ERROR: Analysis of target '//language-packs:intree-codeql' failed; build aborted: error evaluating module extension crate in @@rules_rust+//crate_universe:extension.bzl

with rules_rust 0.49.1, and I've not seen anything in the changelog or source code that'd indicate that upgrading to the latest release would help.

[marvin-hansen]

According to to this engflow blog post, there is a real chance the canonical name will change again in the future...

https://blog.engflow.com/2024/09/06/migrating-to-bazel-modules-aka-bzlmod---repo-names-macros-and-variables/

[konkers]

#2844 Is sufficient for getting all of //examples/bzlmod building and passing tests with bazel version d62e0a0f32188e1875bb8e62ef4377ea4dc1aab2

[marvin-hansen]

I have multiple examples over at the bazel/examples repo that are currently failing with Bazel v8. All examples use the latest rules release 0.50.1

Repro:
https://github.com/marvin-hansen/bazel_8_rust

I don't know if it is the same issue as this one, but I want to bring this up and share the repro.

[marvin-hansen]

The error I am seeing with Bazel 8.0.0-pre.20240826.1 (2024-09-07):

bazel build //...
ERROR: /private/var/tmp/_bazel_marvin/2ca8fbba9913b18ada099dc013e74ad8/external/rules_rust+/crate_universe/private/module_extensions/cargo_bazel_bootstrap.bzl:66:17: Traceback (most recent call last):
        File "/private/var/tmp/_bazel_marvin/2ca8fbba9913b18ada099dc013e74ad8/external/rules_rust+/crate_universe/extension.bzl", line 369, column 37, in _crate_impl
                _generate_hub_and_spokes(module_ctx, cargo_bazel, cfg, annotations, cargo_lockfile = cargo_lockfile, manifests = manifests)
        File "/private/var/tmp/_bazel_marvin/2ca8fbba9913b18ada099dc013e74ad8/external/rules_rust+/crate_universe/extension.bzl", line 139, column 16, in _generate_hub_and_spokes
                cargo_bazel([
        File "/private/var/tmp/_bazel_marvin/2ca8fbba9913b18ada099dc013e74ad8/external/rules_rust+/crate_universe/private/module_extensions/cargo_bazel_bootstrap.bzl", line 66, column 17, in run
                fail("%s returned with exit code %d:\n%s" % (pretty_args, result.return_code, result.stderr
                
                /2ca8fbba9913b18ada099dc013e74ad8/external/rules_rust++rust_host_tools+rust_host_tools/bin/rustc returned with exit code 101:
thread 'main' panicked at src/utils.rs:49:22:
Could not rename paths: Os { code: 2, kind: NotFound, message: "No such file or directory" }
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
ERROR: error evaluating module extension crate in @@rules_rust+//crate_universe:extension.bzl
INFO: Elapsed time: 1.890s
INFO: 0 processes.
ERROR: Build did NOT complete successfully
FAILED: 
    Fetching ... @@rules_rust+//crate_universe:extension.bzl; starting

[tpasternak]

we're getting the same problem with https://github.com/bazelbuild/intellij - we can't call bazel mod deps "" there because of this bug

[criemen]

Fixed by #2908.