CONTRIBUTING.md

Contributing to rustup

1. Fork it!
2. Create your feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -am 'Add some feature'
4. Push to the branch: git push origin my-new-feature
5. Submit a pull request :D

For developing on rustup itself, you may want to install into a temporary directory, with a series of commands similar to this:

$ cargo build
$ mkdir home
$ RUSTUP_HOME=home CARGO_HOME=home target/debug/rustup-init --no-modify-path -y

You can then try out rustup with your changes by running home/bin/rustup, without affecting any existing installation. Remember to keep those two environment variables set when running your compiled rustup-init or the toolchains it installs, but unset when rebuilding rustup itself.

We use rustfmt to keep our codebase consistently formatted. Please ensure that you have correctly formatted your code (most editors will do this automatically when saving) or it may not pass the CI tests.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as in the README, without any additional terms or conditions.

Version numbers

If you ever see a released version of rustup which has :: in its version string then something went wrong with the CI and that needs to be addressed.

We use git-testament to construct our version strings. This records, as a struct, details of the git commit, tag description, and also an indication of modifications to the working tree present when the binary was compiled.

During normal development you may get information from invoking rustup --version which looks like rustup-init 1.18.3+15 (a54051502 2019-05-26) or even rustup-init 1.18.3+15 (a54051502 2019-05-26) dirty 1 modification.

The first part is always the binary name as per clap's normal operation. The version number is a combination of the most recent tag in the git repo, and the number of commits since that tag. The parenthesised information is, naturally, the SHA of the most recent commit and the date of that commit. If the indication of a dirty tree is present, the number of changes is indicated. This combines adds, deletes, modifies, and unknown entries.

You can request further information of a rustup binary with the rustup dump-testament hidden command. It produces output of the form:

$ rustup dump-testament
Rustup version renders as: 1.18.3+15 (a54051502 2019-05-26) dirty 1 modification
Current crate version: 1.18.3
Built from branch: kinnison/version-strings
Commit info: 1.18.3+15 (a54051502 2019-05-26)
Modified: CONTRIBUTING.md

This can be handy when you are testing development versions on your PC and cannot remember exactly which version you had installed, or if you have given a development copy (or instruction to build such) to a user, and wish to have them confirm exactly what they are using.

Finally, we tell git-testament that we trust the stable branch to carry releases. If the build is being performed when not on the stable branch, and the tag and CARGO_PKG_VERSION differ, then the short version string will include both, in the form rustup-init 1.18.3 :: 1.18.2+99 (a54051502 2019-05-26) which indicates the crate version before the rest of the commit. On the other hand, if the build was on the stable branch then regardless of the tag information, providing the commit was clean, the version is always replaced by the crate version. The dump-testament hidden command can reveal the truth however.

Making a release

Before making a release, ensure that rustup-init.sh is behaving correctly, and that you're satisfied that nothing in the ecosystem is breaking because of the update. A useful set of things to check includes verifying that real-world toolchains install okay, and that rls-vscode isn't broken by the release. While it's not our responsibility if they depend on non-stable APIs, we should behave well if we can.

Producing the final release artifacts is a bit involved because of the way Rustup is distributed. The steps for a release are:

1. Update all Cargo.toml to have the new version (optionally make a commit)
2. Run cargo build and review Cargo.lock changes if all looks well, make a commit
3. Update rustup-init.sh version to match the commit details for Cargo.lock
4. Push this to the stable branch (git push origin HEAD:stable)
5. While you wait for green CI, double-check the rustup-init.sh functionality and rustup-init just in case.
6. Ensure all of CI is green on the stable branch. Once it is, check through a representative proportion of the builds looking for the reported version statements to ensure that we definitely built something cleanly which reports as the right version number when run --version.
7. Ping someone in the release team to perform the actual release. They can find instructions in ci/sync-dist.py Note: Some manual testing occurs here, so hopefully they'll catch anything egregious in which case abort the change and roll back.
8. Once the official release has happened, prepare and push a tag of that commit, and also push the content to master
   • git tag -as $VER_NUM -m $VER_NUM (optionally without -s if not GPG signing the tag)
   • git push origin HEAD:master
   • git push origin $VER_NUM

Developer tips and tricks

RUSTUP_FORCE_ARG0

The environment variable RUSTUP_FORCE_ARG0 can be used to get rustup to think its a particular binary, rather than e.g. copying it, symlinking it or other tricks with exec. This is handy when testing particular code paths from cargo run.

$ RUSTUP_FORCE_ARG0=rustup cargo run -- uninstall nightly

RUSTUP_BACKTRACE

By default while running tests, we unset some environment variables that will break our testing (like RUSTUP_TOOLCHAIN, SHELL, ZDOTDIR, RUST_BACKTRACE). But if you want to debug locally, you may need backtrace. RUSTUP_BACKTRACE is used like RUST_BACKTRACE to enable backtraces of failed tests.

NOTE: This is a backtrace for the test, not for any rustup process running in the test

$ RUSTUP_BACKTRACE=1 cargo test --release --test cli-v1 -- remove_toolchain_then_add_again
    Finished release [optimized] target(s) in 0.38s
     Running target\release\deps\cli_v1-1f29f824792f6dc1.exe

running 1 test
test remove_toolchain_then_add_again ... FAILED

failures:

---- remove_toolchain_then_add_again stdout ----
thread 'remove_toolchain_then_add_again' panicked at 'called `Result::unwrap()` on an `Err` value: Os { code: 1142, kind: Other, message: "An attempt was made to create more links on a file than the file system supports." }', src\libcore\result.rs:999:5
stack backtrace:
   0: backtrace::backtrace::trace_unsynchronized
             at C:\Users\appveyor\.cargo\registry\src\github.com-1ecc6299db9ec823\backtrace-0.3.29\src\backtrace\mod.rs:66
   1: std::sys_common::backtrace::_print
             at /rustc/de02101e6d949c4a9040211e9ce8c488a997497e\/src\libstd\sys_common\backtrace.rs:47
   2: std::sys_common::backtrace::print
             at /rustc/de02101e6d949c4a9040211e9ce8c488a997497e\/src\libstd\sys_common\backtrace.rs:36
   3: std::panicking::default_hook::{{closure}}
             at /rustc/de02101e6d949c4a9040211e9ce8c488a997497e\/src\libstd\panicking.rs:198
   4: std::panicking::default_hook
             at /rustc/de02101e6d949c4a9040211e9ce8c488a997497e\/src\libstd\panicking.rs:209
   5: std::panicking::rust_panic_with_hook
             at /rustc/de02101e6d949c4a9040211e9ce8c488a997497e\/src\libstd\panicking.rs:475
   6: std::panicking::continue_panic_fmt
             at /rustc/de02101e6d949c4a9040211e9ce8c488a997497e\/src\libstd\panicking.rs:382
   7: std::panicking::rust_begin_panic
             at /rustc/de02101e6d949c4a9040211e9ce8c488a997497e\/src\libstd\panicking.rs:309
   8: core::panicking::panic_fmt
             at /rustc/de02101e6d949c4a9040211e9ce8c488a997497e\/src\libcore\panicking.rs:85
   9: core::result::unwrap_failed
  10: cli_v1::mock::clitools::setup
  11: alloc::boxed::{{impl}}::call_once<(),FnOnce<()>>
             at /rustc/de02101e6d949c4a9040211e9ce8c488a997497e\src\liballoc\boxed.rs:746
  12: panic_unwind::__rust_maybe_catch_panic
             at /rustc/de02101e6d949c4a9040211e9ce8c488a997497e\/src\libpanic_unwind\lib.rs:82
  13: std::panicking::try
             at /rustc/de02101e6d949c4a9040211e9ce8c488a997497e\src\libstd\panicking.rs:273
  14: std::panic::catch_unwind
             at /rustc/de02101e6d949c4a9040211e9ce8c488a997497e\src\libstd\panic.rs:388
  15: test::run_test::run_test_inner::{{closure}}
             at /rustc/de02101e6d949c4a9040211e9ce8c488a997497e\/src\libtest\lib.rs:1466
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.


failures:
    remove_toolchain_then_add_again

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 26 filtered out

error: test failed, to rerun pass '--test cli-v1'