Merge ref 'ffb9d94dcf4a' from rust-lang/rust

Pull recent changes from https://github.com/rust-lang/rust via Josh.

Upstream ref: ffb9d94dcf4ade0d534842be3672d5e9f47e1333
Filtered ref: 2f31646593733abae36e4c05b5a54acfb9f1f6bc

This merge was created using https://github.com/rust-lang/josh-sync.

Author: The rustc-josh-sync Cronjob Bot

.github/workflows/ci.yml

@@ -45,11 +45,17 @@ jobs:
             os: macos-latest
           - host_target: i686-pc-windows-msvc
             os: windows-latest
+          - host_target: aarch64-pc-windows-msvc
+            os: windows-11-arm
     runs-on: ${{ matrix.os }}
     env:
       HOST_TARGET: ${{ matrix.host_target }}
     steps:
       - uses: actions/checkout@v4
+      - name: apt update
+        if: ${{ startsWith(matrix.os, 'ubuntu') }}
+        # The runners seem to have outdated apt repos sometimes
+        run: sudo apt update
       - name: install qemu
         if: ${{ matrix.qemu }}
         run: sudo apt install qemu-user qemu-user-binfmt
@@ -63,6 +69,12 @@ jobs:
           sudo apt update
           # Install needed packages
           sudo apt install $(echo "libatomic1: zlib1g-dev:" | sed 's/:/:${{ matrix.multiarch }}/g')
+      - name: Install rustup on Windows ARM
+        if: ${{ matrix.os == 'windows-11-arm' }}
+        run: |
+            curl -LOs https://static.rust-lang.org/rustup/dist/aarch64-pc-windows-msvc/rustup-init.exe
+            ./rustup-init.exe -y --no-modify-path
+            echo "$USERPROFILE/.cargo/bin" >> "$GITHUB_PATH"
       - uses: ./.github/workflows/setup
         with:
           toolchain_flags: "--host ${{ matrix.host_target }}"
@@ -147,35 +159,48 @@ jobs:
       - uses: actions/checkout@v4
         with:
           fetch-depth: 256 # get a bit more of the history
-      - name: install josh-proxy
-        run: cargo +stable install josh-proxy --git https://github.com/josh-project/josh --tag r24.10.04
+      - name: install josh-sync
+        run: cargo +stable install --locked --git https://github.com/rust-lang/josh-sync
       - name: setup bot git name and email
         run: |
           git config --global user.name 'The Miri Cronjob Bot'
           git config --global user.email 'miri@cron.bot'
       - name: Install nightly toolchain
         run: rustup toolchain install nightly --profile minimal
-      - name: get changes from rustc
-        run: ./miri rustc-pull
       - name: Install rustup-toolchain-install-master
         run: cargo install -f rustup-toolchain-install-master
-      - name: format changes (if any)
+      - name: Push changes to a branch and create PR
         run: |
+          # Make it easier to see what happens.
+          set -x
+          # Temporarily disable early exit to examine the status code of rustc-josh-sync
+          set +e
+          rustc-josh-sync pull
+          exitcode=$?
+          set -e
+
+          # If there were no changes to pull, rustc-josh-sync returns status code 2.
+          # In that case, skip the rest of the job.
+          if [ $exitcode -eq 2 ]; then
+            echo "Nothing changed in rustc, skipping PR"
+            exit 0
+          elif [ $exitcode -ne 0 ]; then
+            # If return code was not 0 or 2, rustc-josh-sync actually failed
+            echo "error: rustc-josh-sync failed"
+            exit ${exitcode}
+          fi
+
+          # Format changes
           ./miri toolchain
           ./miri fmt --check || (./miri fmt && git commit -am "fmt")
-      - name: Push changes to a branch and create PR
-        run: |
-          # `git diff --exit-code` "succeeds" if the diff is empty.
-          if git diff --exit-code HEAD^; then echo "Nothing changed in rustc, skipping PR"; exit 0; fi
-          # The diff is non-empty, create a PR.
+
+          # Create a PR
           BRANCH="rustup-$(date -u +%Y-%m-%d)"
           git switch -c $BRANCH
           git push -u origin $BRANCH
           gh pr create -B master --title 'Automatic Rustup' --body 'Please close and re-open this PR to trigger CI, then enable auto-merge.'
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          ZULIP_BOT_EMAIL: ${{ secrets.ZULIP_BOT_EMAIL }}
-          ZULIP_API_TOKEN: ${{ secrets.ZULIP_API_TOKEN }}
 
   cron-fail-notify:
     name: cronjob failure notification
@@ -198,7 +223,7 @@ jobs:
           It would appear that the [Miri cron job build]('"https://github.com/$GITHUB_REPOSITORY/actions/runs/$GITHUB_RUN_ID"') failed.
 
           This likely means that rustc changed the miri directory and
-          we now need to do a [`./miri rustc-pull`](https://github.com/rust-lang/miri/blob/master/CONTRIBUTING.md#importing-changes-from-the-rustc-repo).
+          we now need to do a [`rustc-josh-sync pull`](https://github.com/rust-lang/miri/blob/master/CONTRIBUTING.md#importing-changes-from-the-rustc-repo).
 
           Would you mind investigating this issue?
 

.gitignore

@@ -1,5 +1,4 @@
 target
-/doc
 tex/*/out
 *.dot
 *.out

CONTRIBUTING.md

@@ -13,16 +13,20 @@ for a list of Miri maintainers.
 
 [Rust Zulip]: https://rust-lang.zulipchat.com
 
-### Pull review process
+### PR review process
 
 When you get a review, please take care of the requested changes in new commits. Do not amend
 existing commits. Generally avoid force-pushing. The only time you should force push is when there
 is a conflict with the master branch (in that case you should rebase across master, not merge), and
 all the way at the end of the review process when the reviewer tells you that the PR is done and you
-should squash the commits. If you are unsure how to use `git rebase` to squash commits, use `./miri
-squash` which automates the process but leaves little room for customization. (All this is to work
-around the fact that Github is quite bad at dealing with force pushes and does not support `git
-range-diff`. Maybe one day Github will be good at git and then life can become easier.)
+should squash the commits. (All this is to work around the fact that Github is quite bad at
+dealing with force pushes and does not support `git range-diff`.)
+
+The recommended way to squash commits is to use `./miri squash`, which will make everything into a
+single commit. You will be asked for the commit message; please ensure it describes the entire PR.
+You can also use `git rebase` manually if you need more control (e.g. if there should be more than
+one commit at the end), but then please use `--keep-base` to ensure the PR remains based on the same
+upstream commit.
 
 Most PRs bounce back and forth between the reviewer and the author several times, so it is good to
 keep track of who is expected to take the next step. We are using the `S-waiting-for-review` and
@@ -293,25 +297,27 @@ You can also directly run Miri on a Rust source file:
 
 ## Advanced topic: Syncing with the rustc repo
 
-We use the [`josh` proxy](https://github.com/josh-project/josh) to transmit changes between the
+We use the [`josh-sync`](https://github.com/rust-lang/josh-sync) tool to transmit changes between the
 rustc and Miri repositories. You can install it as follows:
 
 ```sh
-cargo +stable install josh-proxy --git https://github.com/josh-project/josh --tag r24.10.04
+cargo install --locked --git https://github.com/rust-lang/josh-sync
 ```
 
-Josh will automatically be started and stopped by `./miri`.
+The commands below will automatically install and manage the [Josh](https://github.com/josh-project/josh) proxy that performs the actual work.
 
 ### Importing changes from the rustc repo
 
 *Note: this usually happens automatically, so these steps rarely have to be done by hand.*
 
 We assume we start on an up-to-date master branch in the Miri repo.
 
+1) First, create a branch for the pull, e.g. `git checkout -b rustup`
+2) Then run the following:
 ```sh
 # Fetch and merge rustc side of the history. Takes ca 5 min the first time.
 # This will also update the `rustc-version` file.
-./miri rustc-pull
+rustc-josh-sync pull
 # Update local toolchain and apply formatting.
 ./miri toolchain && ./miri fmt
 git commit -am "rustup"
@@ -324,12 +330,12 @@ needed.
 
 ### Exporting changes to the rustc repo
 
-We will use the josh proxy to push to your fork of rustc. Run the following in the Miri repo,
+We will use the `josh-sync` tool to push to your fork of rustc. Run the following in the Miri repo,
 assuming we are on an up-to-date master branch:
 
 ```sh
 # Push the Miri changes to your rustc fork (substitute your github handle for YOUR_NAME).
-./miri rustc-push YOUR_NAME miri
+rustc-josh-sync push miri YOUR_NAME
 ```
 
 This will create a new branch called `miri` in your fork, and the output should include a link that
@@ -348,6 +354,7 @@ https. Add the following to your `.gitconfig`:
 
 The following environment variables are relevant to `./miri`:
 
+* `CARGO` sets the binary used to execute Cargo; if none is specified, defaults to `cargo`.
 * `MIRI_AUTO_OPS` indicates whether the automatic execution of rustfmt, clippy and toolchain setup
   (as controlled by the `./auto-*` files) should be skipped. If it is set to `no`, they are skipped.
   This is used to allow automated IDE actions to avoid the auto ops.