chore: Add script to cherry-pick new commits from develop to a release

bin/git/sync-to-release.sh

@@ -0,0 +1,159 @@
+#!/bin/bash -e
+
+set -o pipefail
+
+_usage()
+{
+    self=$( basename -- $( echo $0 ) )
+    cat << USAGE
+Usage: $self release_branch develop_branch working_branch [new_version]
+
+This script is intended to be used to synchronize changes between two
+branches where the "release_branch" has a few insignificant changes (e.g.
+version numbers) compared to the "develop_branch", which has active
+ongoing development. It has not (yet) been tested in scenarios where the
+branches have significantly diverged, or where one has been merged to
+the other.
+
+release_branch: Usually a pending release branch, this is the low
+    activity branch which needs to be updated from develop_branch.
+
+develop_branch: The active development branch.
+
+working_branch: This branch will be created from the release_branch to
+    have the new commits applied. If it exists, it will be assumed to have
+    been created by an earlier invocation, and will be used for
+    comparisons instead of release_branch.  When the script is done, this
+    branch will NOT be pushed. The user must manually push the branch and
+    create a pull request.
+
+new_version: OPTIONAL. If provided, will update the version string in
+    BuildInfo.cpp to this value, and create a version_setting commit.
+
+USAGE
+    if [[ $# -ne 0 ]]; then
+        echo "Error: ${@}"
+        echo
+    fi
+
+    exit 1
+}
+
+if [[ $# -lt 3 || $# -gt 4 ]]; then
+    _usage
+fi
+
+release_branch="$1"
+shift
+
+develop_branch="$1"
+shift
+
+working_branch="$1"
+shift
+
+if [[ $# -ne 0 ]]; then
+    new_version="$1"
+    shift
+fi
+
+_run()
+{
+    echo
+    echo "\$ ${@}"
+    "${@}"
+}
+
+if git rev-parse --quiet --verify --end-of-options "refs/heads/${working_branch}" > /dev/null; then
+    release_branch="${working_branch}"
+    _run git checkout "${working_branch}"
+else
+    _run git checkout --no-track -B "${working_branch}" "${release_branch}"
+fi
+
+
+# Fetch if it hasn't been done in a while
+if find "$( git rev-parse --git-dir )/FETCH_HEAD" -type f -mmin +10 | grep -q "FETCH"; then
+    _run git fetch --all
+fi
+
+temp=$( mktemp )
+
+# The "word-diff" option doesn't seem to have any meaningful effect on the output.
+# This may make this script fragile across git versions with differing output formats.
+_run git range-diff --word-diff=porcelain --no-patch --right-only \
+    "${release_branch}"..."${develop_branch}" | tee "${temp}"
+
+first_commit=$( cat "${temp}" | \
+    awk '( $1 == "-:" && $2 ~ /-+/ && $3 == ">" ) { print $5; exit; }'  )
+
+if [[ "${first_commit}" == "" && "${new_version}" == "" ]]; then
+    _usage No divergence found
+    exit 1
+fi
+
+if [[ "${first_commit}" == "" ]]; then
+    echo -e "\nNo divergence found. Continue to update version number"
+else
+    echo -e "\nFound first unique commit in ${develop_branch}: ${first_commit}"
+
+    first_commit=$( git rev-parse --quiet "${first_commit}" )
+
+    echo "Full commit ID is: ${first_commit}"
+
+    merge_base=$( git merge-base --octopus "${first_commit}" "${develop_branch}" )
+    if [[ "${first_commit}" != "${merge_base}" ]]; then
+        echo "Bad first commit: ${first_commit} is not an ancestor of ${develop_branch}"
+        exit 1
+    fi
+
+    _run git diff "${first_commit}~" "${release_branch}"
+
+    read -n 1 -s -p "Does the diff look reasonable? (y to continue / any other key to abort)" continue
+    echo
+    if [[ ! ( "${continue}" =~ [yY] ) ]]; then
+        echo Abort
+        exit 1
+    fi
+
+    # Dilemma: if the cherry-pick is interrupted, for example, because of a conflict, the script
+    # will abort, and can not easily be resumed. This will prevent the final step(s) from running.
+    if ! _run git cherry-pick --empty=drop "${first_commit}~..${develop_branch}"; then
+        # Solution: if the cherry-pick is interrupted, run the command again.
+        if [[ "${new_version}" != "" ]]; then
+            echo
+            echo "Cherry pick failed or was interrupted. Resolve issues, finish the"
+            echo "  cherry pick, then run this script again to with the same parameters"
+            echo "  to update the version number."
+        fi
+        exit 1
+    fi
+
+    if [[ "${new_version}" == "" ]]; then
+        # If there is no version number change to make, we're done.
+        exit 0
+    fi
+fi
+
+# There should only be one matching file, but loop in case not.
+buildfiles=( $( git ls-files | grep "BuildInfo.cpp" ) )
+
+for build in "${buildfiles[@]}"; do
+    sed 's/\(^.*versionString =\).*$/\1 "'${new_version}'"/' ${build} > version.cpp && \
+    _run diff "${build}" version.cpp && exit 1 || \
+    mv -vi version.cpp ${build}
+
+    git add ${build}
+done
+
+_run git commit -S -m "Set version to ${new_version}"
+
+_run git log --oneline --first-parent ${release_branch}^..
+
+cat << PUSH
+
+-------------------------------------------------------------------
+This script will not push to remote. Verify everything is correct,
+then push, and create a PR as described in CONTRIBUTING.md.
+-------------------------------------------------------------------
+PUSH