bootstrap.example.toml: use less contextual format #142636

lolbinarycat · 2025-06-17T17:31:07Z

prefixing each key with its section means you don't need to scroll up 4 pages to see which section
a particular key is from.

target specific options were kept in old format since the exact section name depends on the target, so those options must now be moved to the bottom of the file.

inspired by zulip discussion

r? @workingjubilee

prefixing each key with its section means you don't need to scroll up 4 pages to see which section a particular key is from. target specific options were kept in old format since the exact section name depends on the target, so those options must now be moved to the bottom of the file.

rustbot · 2025-06-17T17:31:13Z

This PR modifies bootstrap.example.toml.

If appropriate, please update CONFIG_CHANGE_HISTORY in src/bootstrap/src/utils/change_tracker.rs.

Kobzol · 2025-06-17T18:46:18Z

Note that the Python part of bootstrap parses this file, so it will probably require some changes in it 🥶

workingjubilee · 2025-06-17T19:08:14Z

bootstrap.example.toml

+#llvm.clang = false

 # Whether to enable llvm compilation warnings.
-#enable-warnings = false
+#llvm.enable-warnings = false

 # Custom CMake defines to set when building LLVM.
-#build-config = {}
+#llvm.build-config = {}

 # =============================================================================
 # Tweaking how GCC is compiled
 # =============================================================================
-[gcc]
 # Download GCC from CI instead of building it locally.
 # Note that this will attempt to download GCC even if there are local
 # modifications to the `src/gcc` submodule.
 # Currently, this is only supported for the `x86_64-unknown-linux-gnu` target.
-#download-ci-gcc = false
+#gcc.download-ci-gcc = false


I forget. If we have a sequence like this:

llvm.clang = false gcc.download-ci-gcc = false llvm.enable-warnings = false

does that still parse correctly as toml?

According to https://www.toml-lint.com/ and https://pseitz.github.io/toml-to-json-online-converter/ it does.

https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=23021a5f34e12891223fcaba97e4f37d

cool, that was the one thing I was wondering about.

There was a point during the TOML spec discussions leading up to 1.0 where some of us argued we should not allow this.

rustbot assigned workingjubilee Jun 17, 2025

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-bootstrap Relevant to the bootstrap subteam: Rust's build system (x.py and src/bootstrap) labels Jun 17, 2025