Add contrib/sync-upstream.sh script to automate merging upstream PRs

.gitignore

@@ -51,3 +51,4 @@ build-aux/compile
 build-aux/test-driver
 src/stamp-h1
 libsecp256k1.pc
+contrib/gh-pr-create.sh

contrib/sync-upstream.sh

@@ -0,0 +1,111 @@
+#!/bin/bash
+
+set -eou pipefail
+
+help() {
+    echo "$0 range [end]"
+    echo "    merges every merge commit missing merge commit."
+    echo "    If the optional [end] commit is provided, only merges up to [end]."
+    echo
+    echo "$0 select <commit> ... <commit>"
+    echo "    merges every selected merge commit"
+    echo
+    echo "This tool creates a branch and a script that can be executed to create the"
+    echo "PR automatically. The script requires the github-cli tool (aka gh)."
+    echo ""
+    echo "Tip: \`git log --oneline upstream/master --merges\` shows merge commits."
+    exit 1
+}
+
+if [ "$#" -lt 1 ]; then
+    help
+fi
+
+REMOTE=upstream
+REMOTE_BRANCH=$REMOTE/master
+# Makes sure you have a remote "upstream" that is up-to-date
+setup() {
+    ret=0
+    git fetch $REMOTE &> /dev/null || ret=$?
+    if [ ${ret} == 0 ]; then
+        return
+    fi
+    echo "Adding remote \"$REMOTE\" with URL git@github.com:bitcoin-core/secp256k1.git. Continue with y"
+    read -r yn
+    case $yn in
+        [Yy]* ) ;;
+        * ) exit 1;;
+    esac
+    git remote add $REMOTE git@github.com:bitcoin-core/secp256k1.git &> /dev/null
+    git fetch $REMOTE &> /dev/null
+}
+
+range() {
+    RANGESTART_COMMIT=$(git merge-base $REMOTE_BRANCH master)
+    RANGEEND_COMMIT=$REMOTE_BRANCH
+    if [ "$#" = 1 ]; then
+        RANGEEND_COMMIT=$1
+    fi
+
+    COMMITS=$(git --no-pager log --oneline "$REMOTE_BRANCH" --merges "$RANGESTART_COMMIT".."$RANGEEND_COMMIT")
+    COMMITS=$(echo "$COMMITS" | tac | awk '{ print $1 }' ORS=' ')
+    echo "Merging $COMMITS. Continue with y"
+    read -r yn
+    case $yn in
+        [Yy]* ) ;;
+        * ) exit 1;;
+    esac
+}
+
+case $1 in
+    range)
+        shift
+        setup
+        range "$@"
+        ;;
+    select)
+        shift
+        setup
+        COMMITS=$*
+        ;;
+    help)
+        help
+        ;;
+    *)
+        help
+esac
+
+TITLE="Upstream PRs "
+BODY=""
+for COMMIT in $COMMITS
+do
+    PRNUM=$(git log -1 "$COMMIT" --pretty=format:%s | sed s/'Merge #\([0-9]*\).*'/'\1'/)
+    TITLE="$TITLE #$PRNUM"
+    BODY=$(printf "%s\n%s" "$BODY" "$(git log -1 "$COMMIT" --pretty=format:%s | sed s/'Merge #\([0-9]*\)'/'[upstream PR #\1]'/)")
+done
+
+BODY=$(printf "%s\n\n%s" "$BODY" "This PR was automatically created with \\\`$0 $*\\\`.")
+
+echo "-----------------------------------"
+echo "$TITLE"
+echo "-----------------------------------"
+echo "$BODY"
+echo "-----------------------------------"
+# Create branch from PR commit and create PR
+git checkout master
+git pull
+git checkout -b temp-merge-"$PRNUM"
+
+BASEDIR=$(dirname "$0")
+FNAME=$BASEDIR/gh-pr-create.sh
+cat <<EOT > "$FNAME"
+#!/bin/sh
+gh pr create -t "$TITLE" -b "$BODY" --web
+# Remove temporary branch
+git checkout master
+git branch -D temp-merge-"$PRNUM"
+EOT
+chmod +x "$FNAME"
+echo Run "$FNAME" after solving the merge conflicts
+
+git merge --no-edit -m "Merge commits '$COMMITS' into temp-merge-$PRNUM" $COMMITS