Allow linking rustc and rustdoc against the same single tracing crate

By consecutively initializing `tracing` and `rustc_log`, Rustdoc assumes
that these involve 2 different tracing crates.

I would like to be able to build rustdoc against the same tracing crate
that rustc_log is also built against. Previously this arrangement would
crash rustdoc:

    thread 'main' panicked at rust/compiler/rustc_log/src/lib.rs:142:65:
    called `Result::unwrap()` on an `Err` value: SetGlobalDefaultError("a global default trace dispatcher has already been set")
    stack backtrace:
       0: rust_begin_unwind
       1: core::panicking::panic_fmt
       2: core::result::unwrap_failed
       3: rustc_log::init_logger
       4: rustc_driver_impl::init_logger
       5: rustdoc::main
    note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

    error: the compiler unexpectedly panicked. this is a bug.

    note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-rustdoc&template=ice.md

    note: please make sure that you have updated to the latest nightly

    query stack during panic:
    end of query stack
2 files changed
tree: 5ad573dadb72a0e30d599f41b51aadb5d4cb17ab
  1. .github/
  2. compiler/
  3. library/
  4. LICENSES/
  5. src/
  6. tests/
  7. .clang-format
  8. .editorconfig
  9. .git-blame-ignore-revs
  10. .gitattributes
  11. .gitignore
  12. .gitmodules
  13. .ignore
  14. .mailmap
  15. bootstrap.example.toml
  16. Cargo.lock
  17. Cargo.toml
  18. CODE_OF_CONDUCT.md
  19. configure
  20. CONTRIBUTING.md
  21. COPYRIGHT
  22. INSTALL.md
  23. LICENSE-APACHE
  24. license-metadata.json
  25. LICENSE-MIT
  26. README.md
  27. RELEASES.md
  28. REUSE.toml
  29. rust-bors.toml
  30. rustfmt.toml
  31. triagebot.toml
  32. x
  33. x.ps1
  34. x.py
README.md

Website | Getting started | Learn | Documentation | Contributing

This is the main source code repository for Rust. It contains the compiler, standard library, and documentation.

Why Rust?

  • Performance: Fast and memory-efficient, suitable for critical services, embedded devices, and easily integrated with other languages.

  • Reliability: Our rich type system and ownership model ensure memory and thread safety, reducing bugs at compile-time.

  • Productivity: Comprehensive documentation, a compiler committed to providing great diagnostics, and advanced tooling including package manager and build tool (Cargo), auto-formatter (rustfmt), linter (Clippy) and editor support (rust-analyzer).

Quick Start

Read “Installation” from The Book.

Installing from Source

If you really want to install from source (though this is not recommended), see INSTALL.md.

Getting Help

See https://www.rust-lang.org/community for a list of chat platforms and forums.

Contributing

See CONTRIBUTING.md.

License

Rust is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0), with portions covered by various BSD-like licenses.

See LICENSE-APACHE, LICENSE-MIT, and COPYRIGHT for details.

Trademark

The Rust Foundation owns and protects the Rust and Cargo trademarks and logos (the “Rust Trademarks”).

If you want to use these names or brands, please read the Rust language trademark policy.

Third-party logos may be subject to third-party copyrights and trademarks. See Licenses for details.