status-mobile/scripts/hooks/prepare-commit-msg

#!/usr/bin/env bash
set -eo pipefail

if [[ -z $(git diff --cached --name-only -r | grep status-go-version.json) ]]; then
  exit 0 # No status-go-version.json changes found.
fi

# MacOS sed is garbage and interprets newlines differently.
[[ "$(uname)" -eq "Darwin" ]] && NL=$'\\\n' || NL="\n"

MERGE_BASE=$(git merge-base -a develop "$(git rev-parse --abbrev-ref HEAD)" develop)
GO_COMMIT_MERGE_BASE=$(git show "${MERGE_BASE}":status-go-version.json | awk -F'"' '/commit-sha1/{print $4}')
GO_COMMIT_CURRENT=$(awk -F'"' '/commit-sha1/{print $4}' status-go-version.json)
GITHUB_LINK_PREFIX="https://github.com/status-im/status-go/compare/"
# Link to the current StatusGo changelog being updated.
GITHUB_LINK="${GITHUB_LINK_PREFIX}${GO_COMMIT_MERGE_BASE::8}...${GO_COMMIT_CURRENT::8}"

COMMIT_MSG_FILE=$1
# Check if the commit message already contains the link (rebase) and update otherwise insert into line2
if ! grep -qF "${GITHUB_LINK_PREFIX}" "${COMMIT_MSG_FILE}" >/dev/null; then
  sed -in'' -e "2i\\
${NL}${GITHUB_LINK}" "${COMMIT_MSG_FILE}"
else
  sed -in'' -e "s;^${GITHUB_LINK_PREFIX}.*$;${GITHUB_LINK};" "${COMMIT_MSG_FILE}"
fi