Upgrading the Rust Toolchain on Chrome OS

WARNING: These steps are only general in nature. Sometimes things can go wrong, especially with applying patches. This is expected to happen and best judgement should be used.

Follow these steps to upgrade the rust ebuild.

DEL_VERSION=1.33.0 # Previous version (to be deleted)
OLD_VERSION=1.34.0 # Current version
NEW_VERSION=1.35.0 # New version

# Be sure cross-compilers have been emerged.
target_triples=( $(awk '/^RUSTC_TARGET_TRIPLES=\(/ { emit=1; next } /^)/ { if (emit) exit } /-cros-/ { if (emit) { print $1 } }' "rust-${OLD_VERSION}.ebuild") )
for x in "${target_triples[@]}"; do command -v "${x}-clang" >/dev/null || sudo emerge -G "cross-${x}/gcc"; done

# Copy ebuild for the new version.
cp rust-${OLD_VERSION}.ebuild rust-${NEW_VERSION}.ebuild
git add rust-${NEW_VERSION}.ebuild
git rm rust-${DEL_VERSION}.ebuild

# Download Rust's source.
curl -f "https://static.rust-lang.org/dist/${src_tarfile_name}" -o "${rust_src}"

# Verify the signature of the source
curl -f "https://static.rust-lang.org/dist/${src_tarfile_name}.asc" -o "${sig_file}"
gpg --verify "${sig_file}" "${rust_src}"

# ^^ If the above fails with:
# ```
# gpg: Can't check signature: No public key
# ```
# then you need to import the rustc key:
# curl https://keybase.io/rust/pgp_keys.asc | gpg --import
# Once you've done that, please try again.

# Copy source to localmirror.
gsutil cp -n -a public-read "${rust_src}" "gs://chromeos-localmirror/distfiles/${src_tarfile_name}"

# Copy patches for the new version.
for x in files/rust-${OLD_VERSION}-*.patch; do cp $x ${x//${OLD_VERSION}/${NEW_VERSION}}; done
git add files/rust-${NEW_VERSION}-*.patch
git rm files/rust-${DEL_VERSION}-*.patch

# Set `STAGE0_DATE` to date from `https://github.com/rust-lang/rust/blob/${NEW_VERSION}/src/stage0.txt`.
STAGE0_DATE=$(curl https://raw.githubusercontent.com/rust-lang/rust/${NEW_VERSION}/src/stage0.txt | \
  grep date: | sed -e 's/date: //')
sed -i -e 's/STAGE0_DATE=.*/STAGE0_DATE="'${STAGE0_DATE}'"/' rust-${NEW_VERSION}.ebuild
git add rust-${NEW_VERSION}.ebuild

# Add mirror to the `RESTRICT` variable.
sed -i -e 's/RESTRICT="\(.*\)"/RESTRICT="\1 mirror"/' rust-${NEW_VERSION}.ebuild

# Update manifest checksums.
ebuild rust-${NEW_VERSION}.ebuild manifest
git add Manifest

# Remove mirror from `RESTRICT` variable.
sed -i -e 's/RESTRICT="\(.*\) mirror"/RESTRICT="\1"/' rust-${NEW_VERSION}.ebuild

# Build the new compiler.
ebuild rust-${NEW_VERSION}.ebuild compile

# Fix patches as needed and add them to git. There is no command for this because there is no fixed
# set of things to do to fix broken patches. One method would be to checkout the rust source to
# `$OLD_VERSION` and `git apply` the broken patch and commit it. Then, checkout `$NEW_VERSION` and
# cherry-pick the commit from the previous step. Now the repo should be in a good position to fix
# merge conflicts as one normally does. Once resolved and committed, generate a patch from that
# commit and copy it to the new patch version.

# Build the new compiler again with the udpated checksums.
ebuild rust-${NEW_VERSION}.ebuild compile

# Install the compiler in the chroot.
sudo ebuild rust-${NEW_VERSION}.ebuild merge

# Upgrade rust package in `profiles/targets/chromeos/package.provided`
sed -i -e "s#dev-lang/rust-${DEL_VERSION}#dev-lang/rust-${NEW_VERSION}#" \
git add ../../profiles/targets/chromeos/package.provided

# Add a virtual/rust ebuild for the new version.
cp ../../virtual/rust/rust-${OLD_VERSION}.ebuild ../../virtual/rust/rust-${NEW_VERSION}.ebuild
git add ../../virtual/rust/rust-${NEW_VERSION}.ebuild
git rm ../../virtual/rust/rust-${DEL_VERSION}.ebuild
  • Update this document with additional tips or any steps that have changed.

  • Upload change for review. CC reviewers from previous upgrade.

  • Remember to add Cq-Include-Trybots: chromeos/cq:cq-llvm-orchestrator to your commit message

  • Kick off try-job: cros tryjob -g <cl number> chromiumos-sdk-tryjob.