teach ./miri how to do Josh syncs

2 files changed, 89 insertions, 44 deletions

diff --git a/src/tools/miri/CONTRIBUTING.md b/src/tools/miri/CONTRIBUTING.md
index b1e6b9c69d3..b18083849cf 100644
--- a/src/tools/miri/CONTRIBUTING.md
+++ b/src/tools/miri/CONTRIBUTING.md
@@ -290,14 +290,12 @@ cargo run --release -p josh-proxy -- --local=$(pwd)/local --remote=https://githu
 
 ### Importing changes from the rustc repo
 
+Josh needs to be running, as described above.
 We assume we start on an up-to-date master branch in the Miri repo.
 
 ```sh
-# Fetch rustc side of the history. Takes ca 5 min the first time.
-# Do NOT change that commit ID, it needs to be exactly this!
-git fetch http://localhost:8000/rust-lang/rust.git:at_commit=75dd959a3a40eb5b4574f8d2e23aa6efbeb33573[:prefix=src/tools/miri]:/src/tools/miri.git master
-# Include that history into ours.
-git merge FETCH_HEAD -m "merge rustc history"
+# Fetch and merge rustc side of the history. Takes ca 5 min the first time.
+./miri rustc-pull
 # Update toolchain reference and apply formatting.
 ./rustup-toolchain HEAD && ./miri fmt
 git commit -am "rustup"
@@ -310,16 +308,15 @@ needed.
 
 ### Exporting changes to the rustc repo
 
-We will use the josh proxy to push to your fork of rustc. You need to make sure
-that the master branch of your fork is up-to-date. Also make sure that there
-exists no branch called `miri` in your fork. Then run the following in the Miri
-repo, assuming we are on an up-to-date master branch:
+Josh needs to be running, as described above. We will use the josh proxy 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).
-# Do NOT change that commit ID, it needs to be exactly this!
-git push http://localhost:8000/YOUR_NAME/rust.git:at_commit=75dd959a3a40eb5b4574f8d2e23aa6efbeb33573[:prefix=src/tools/miri]:/src/tools/miri.git -o base=master HEAD:miri
+./miri rustc-push YOUR_NAME miri
 ```
 
-This will create a new branch in your fork, and the output should include a link
-to create a rustc PR that will integrate those changes into the main repository.
+This will create a new branch called 'miri' in your fork, and the output should
+include a link to create a rustc PR that will integrate those changes into the
+main repository.
diff --git a/src/tools/miri/miri b/src/tools/miri/miri
index e492308a62e..662f2b8e631 100755
--- a/src/tools/miri/miri
+++ b/src/tools/miri/miri
@@ -42,6 +42,15 @@ many different seeds.
 Runs the benchmarks from bench-cargo-miri in hyperfine. hyperfine needs to be installed.
 <benches> can explicitly list the benchmarks to run; by default, all of them are run.
 
+./miri rustc-pull:
+Pull and merge Miri changes from the rustc repo.
+
+./miri rustc-push <github user> <branch>:
+Push Miri changes back to the rustc repo. This will update the 'master' branch
+in the Rust fork of the given user to upstream. It will also pull a copy of the
+rustc history into the Miri repo, unless you set the RUSTC_GIT env var to an
+existing clone of the rustc repo.
+
   ENVIRONMENT VARIABLES
 
 MIRI_SYSROOT:
@@ -52,37 +61,60 @@ Pass extra flags to all cargo invocations. (Ignored by `./miri cargo`.)
 EOF
 )
 
-## We need to know where we are.
+## We need to know which command to run and some global constants.
+COMMAND="$1"
+if [ -z "$COMMAND" ]; then
+    echo "$USAGE"
+    exit 1
+fi
+shift
 # macOS does not have a useful readlink/realpath so we have to use Python instead...
 MIRIDIR=$(python3 -c 'import os, sys; print(os.path.dirname(os.path.realpath(sys.argv[1])))' "$0")
+# Used for rustc syncs.
+JOSH_FILTER=":at_commit=75dd959a3a40eb5b4574f8d2e23aa6efbeb33573[:prefix=src/tools/miri]:/src/tools/miri"
 
-## Run the auto-things.
-if [ -z "$MIRI_AUTO_OPS" ]; then
-    export MIRI_AUTO_OPS=42
-
-    # Run this first, so that the toolchain doesn't change after
-    # other code has run.
-    if [ -f "$MIRIDIR/.auto-everything" ] || [ -f "$MIRIDIR/.auto-toolchain" ] ; then
-        (cd "$MIRIDIR" && ./rustup-toolchain)
+## Early commands, that don't do auto-things and don't want the environment-altering things happening below.
+case "$COMMAND" in
+rustc-pull)
+    cd "$MIRIDIR"
+    git fetch http://localhost:8000/rust-lang/rust.git$JOSH_FILTER.git master
+    git merge FETCH_HEAD
+    exit 0
+    ;;
+rustc-push)
+    USER="$1"
+    BRANCH="$2"
+    if [ -z "$USER" ] || [ -z "$BRANCH" ]; then
+        echo "Usage: $0 rustc-push <github user> <branch>"
+        exit 1
     fi
-
-    if [ -f "$MIRIDIR/.auto-everything" ] || [ -f "$MIRIDIR/.auto-fmt" ] ; then
-        $0 fmt
+    if [ -n "$RUSTC_GIT" ]; then
+        # Use an existing fork for the branch updates.
+        cd "$RUSTC_GIT"
+    else
+        # Do this in the local Miri repo.
+        echo "This will pull a copy of the rust-lang/rust history into this Miri checkout, growing it by about 1GB."
+        read -r -p "To avoid that, abort now and set the RUSTC_GIT environment variable to an existing rustc checkout. Proceed? [y/N] "
+        if [[ ! $REPLY =~ ^[Yy]$ ]]; then
+            exit 1
+        fi
+        cd "$MIRIDIR"
     fi
-
-    if [ -f "$MIRIDIR/.auto-everything" ] || [ -f "$MIRIDIR/.auto-clippy" ] ; then
-        $0 clippy -- -D warnings
+    # Prepare the branches. For reliable pushing we need to push to a non-existent branch
+    # and set `-o base` to a branch that holds current rustc master.
+    echo "Preparing $USER/rust..."
+    if git fetch https://github.com/$USER/rust $BRANCH &>/dev/null; then
+        echo "The '$BRANCH' seems to already exist in $USER/rust. Please delete it and try again."
+        exit 1
     fi
-fi
-
-## Determine command and toolchain.
-COMMAND="$1"
-[ $# -gt 0 ] && shift
-# Doing this *after* auto-toolchain logic above, since that might change the toolchain.
-TOOLCHAIN=$(cd "$MIRIDIR"; rustup show active-toolchain | head -n 1 | cut -d ' ' -f 1)
-
-## Handle some commands early, since they should *not* alter the environment.
-case "$COMMAND" in
+    git fetch https://github.com/rust-lang/rust master
+    git push https://github.com/$USER/rust FETCH_HEAD:master
+    # Do the actual push.
+    cd "$MIRIDIR"
+    echo "Pushing Miri changes..."
+    git push http://localhost:8000/$USER/rust.git$JOSH_FILTER.git HEAD:$BRANCH -o base=master
+    exit 0
+    ;;
 many-seeds)
     for SEED in $({ echo obase=16; seq 0 255; } | bc); do
         echo "Trying seed: $SEED"
@@ -106,9 +138,28 @@ bench)
     ;;
 esac
 
+## Run the auto-things.
+if [ -z "$MIRI_AUTO_OPS" ]; then
+    export MIRI_AUTO_OPS=42
+
+    # Run this first, so that the toolchain doesn't change after
+    # other code has run.
+    if [ -f "$MIRIDIR/.auto-everything" ] || [ -f "$MIRIDIR/.auto-toolchain" ] ; then
+        (cd "$MIRIDIR" && ./rustup-toolchain)
+    fi
+
+    if [ -f "$MIRIDIR/.auto-everything" ] || [ -f "$MIRIDIR/.auto-fmt" ] ; then
+        $0 fmt
+    fi
+
+    if [ -f "$MIRIDIR/.auto-everything" ] || [ -f "$MIRIDIR/.auto-clippy" ] ; then
+        $0 clippy -- -D warnings
+    fi
+fi
+
 ## Prepare the environment
 # Determine some toolchain properties
-# export the target so its available in miri
+TOOLCHAIN=$(cd "$MIRIDIR"; rustup show active-toolchain | head -n 1 | cut -d ' ' -f 1)
 TARGET=$(rustc +$TOOLCHAIN --version --verbose | grep "^host:" | cut -d ' ' -f 2)
 SYSROOT=$(rustc +$TOOLCHAIN --print sysroot)
 LIBDIR=$SYSROOT/lib/rustlib/$TARGET/lib
@@ -227,10 +278,7 @@ cargo)
     $CARGO "$@"
     ;;
 *)
-    if [ -n "$COMMAND" ]; then
-      echo "Unknown command: $COMMAND"
-      echo
-    fi
-    echo "$USAGE"
+    echo "Unknown command: $COMMAND"
     exit 1
+    ;;
 esac