From a86e533c3d7d6b330fe8adbc4c6e81b1dc86f42a Mon Sep 17 00:00:00 2001
From: jennyhickson <61183013+jennyhickson@users.noreply.github.com>
Date: Wed, 7 Jan 2026 13:19:44 +0000
Subject: [PATCH 1/4] create new script

---
 sbin/gh_manage_milestones | 140 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 140 insertions(+)
 create mode 100755 sbin/gh_manage_milestones

diff --git a/sbin/gh_manage_milestones b/sbin/gh_manage_milestones
new file mode 100755
index 0000000..33b8ffb
--- /dev/null
+++ b/sbin/gh_manage_milestones
@@ -0,0 +1,140 @@
+#!/usr/bin/env bash
+
+# ----------------------------------------------------------------------------
+# (C) Crown copyright Met Office. All rights reserved.
+# The file LICENCE, distributed with this code, contains details of the terms
+# under which the code may be used.
+# ----------------------------------------------------------------------------
+
+# Script to create, update and close milestones in multiple GitHub repositories
+# Requires GitHub CLI: https://cli.github.com/ and Admin privileges to the repos
+
+set -euo pipefail
+
+usage() {
+  cat <<EOF
+Usage: ${0##*/} -t <title> [options]
+  -t <title>       Title of milestone to be created, updated or closed.
+  -c               Close milestone. Otherwise will create a new milestone or
+                   update an existing milestone.
+  -d <due on>      Milestone due date. Format: YYYY-MM-DDTHH:MM:SSZ
+  -p <description> Description of the milestone
+  -n               Dry Run, print actions without making changes
+  -h, --help       Show this help message
+
+Examples:
+  # Create a new milestone
+  ${0##*/} -t <title> [-d YYYY-MM-DDTHH:MM:SSZ] [-p <description>]
+
+  # Update all milestones with a new date
+  ${0##*/} -t <title> -d <YYYY-MM-DDTHH:MM:SSZ>
+
+  # Close a milestone
+  ${0##*/} -t <title> -c
+EOF
+  exit 1
+}
+
+# -- Defaults
+STATE="open"
+TITLE=""
+DUE=""
+DESC=""
+DRY_RUN=0
+
+# -- Parse options
+while getopts "t:d:p:cnh-:" opt; do
+  case $opt in
+    t) TITLE="$OPTARG" ;;
+    c) STATE="closed" ;;
+    d) DUE="$OPTARG" ;;
+    p) DESC="$OPTARG" ;;
+    n) DRY_RUN=1 ;;
+    h) usage ;;
+    -) [ "$OPTARG" = "help" ] && usage ;;
+    *) usage ;;
+  esac
+done
+
+# -- Modify milestones in relevant repositories
+repos=(
+  "MetOffice/um"
+  "MetOffice/jules"
+  "MetOffice/lfric_apps"
+  "MetOffice/lfric_core"
+  "MetOffice/ukca"
+  "MetOffice/casim"
+  "MetOffice/socrates"
+  "MetOffice/um_doc"
+  "MetOffice/simulation-systems"
+  "MetOffice/SimSys_Scripts"
+  "MetOffice/git_playground"
+)
+#
+# -- Helper functions
+get_milestone_number(){
+  local repo_name="$1"
+
+  gh api /repos/${repo_name}/milestones --jq ".[] | select(.title == \"${TITLE}\") | .number"
+}
+
+run_command(){
+  local gh_command="$1"
+
+  if (( DRY_RUN )); then
+    echo "[DRY RUN] $gh_command"
+  else
+    eval "$gh_command"
+  fi
+}
+
+# -- Change milestone for each repository
+
+for repo in "${repos[@]}"; do
+  echo "Processing milestone in repository: $repo"
+
+
+  # -- If milestone exists then fetch the number
+  NUMBER=0
+  if [[ $(gh api /repos/${repo}/milestones --jq ".[] | select(.title == \"${TITLE}\")") ]]; then
+    NUMBER=$(get_milestone_number "${repo}")
+    echo "${TITLE} in ${repo} is milestone ${NUMBER}"
+  else
+    echo "Milestone does not exist in ${repo}"
+  fi
+
+  # -- Build GH command from optional arguments.
+  GH_COMMAND="gh api -f \"title=${TITLE}\""
+  if [[ ${DUE} ]]; then
+    GH_COMMAND=$GH_COMMAND" -f \"due_on=${DUE}\""
+  fi
+  if [[ ${DESC} ]]; then
+    GH_COMMAND=$GH_COMMAND" -f \"description=${DESC}\""
+  fi
+
+  if [[ "$STATE" == "open" ]]; then
+
+    if (( NUMBER )); then
+      echo "Updating milestone"
+      GH_COMMAND=$GH_COMMAND" --method PATCH"
+      GH_COMMAND=$GH_COMMAND" /repos/${repo}/milestones/${NUMBER}"
+      run_command "${GH_COMMAND}"
+    else
+      echo "Creating new milestone"
+      GH_COMMAND=$GH_COMMAND" --method POST"
+      GH_COMMAND=$GH_COMMAND" /repos/${repo}/milestones"
+      run_command "${GH_COMMAND}"
+    fi
+    
+  else
+
+    if (( NUMBER )); then
+      echo "Closing milestone"
+      GH_COMMAND=$GH_COMMAND" --method PATCH"
+      GH_COMMAND=$GH_COMMAND" /repos/${repo}/milestones/${NUMBER}"
+      GH_COMMAND=$GH_COMMAND" -f \"state=closed\""
+      run_command "${GH_COMMAND}"
+    fi
+  fi
+
+done

From 611c4bf8b289f46638927bb5ddd74dee17ac4431 Mon Sep 17 00:00:00 2001
From: jennyhickson <61183013+jennyhickson@users.noreply.github.com>
Date: Wed, 7 Jan 2026 13:34:37 +0000
Subject: [PATCH 2/4] tidy up

---
 sbin/gh_manage_milestones | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/sbin/gh_manage_milestones b/sbin/gh_manage_milestones
index 33b8ffb..7d25161 100755
--- a/sbin/gh_manage_milestones
+++ b/sbin/gh_manage_milestones
@@ -74,10 +74,14 @@ repos=(
 # -- Helper functions
 get_milestone_number(){
   local repo_name="$1"
-
   gh api /repos/${repo_name}/milestones --jq ".[] | select(.title == \"${TITLE}\") | .number"
 }
 
+check_exists(){
+  local repo_name="$1"
+  gh api /repos/${repo_name}/milestones --jq ".[] | select(.title == \"${TITLE}\")"
+}
+
 run_command(){
   local gh_command="$1"
 
@@ -88,6 +92,7 @@ run_command(){
   fi
 }
 
+
 # -- Change milestone for each repository
 
 for repo in "${repos[@]}"; do
@@ -96,7 +101,7 @@ for repo in "${repos[@]}"; do
 
   # -- If milestone exists then fetch the number
   NUMBER=0
-  if [[ $(gh api /repos/${repo}/milestones --jq ".[] | select(.title == \"${TITLE}\")") ]]; then
+  if [[ $(check_exists "${repo}") ]]; then
     NUMBER=$(get_milestone_number "${repo}")
     echo "${TITLE} in ${repo} is milestone ${NUMBER}"
   else
@@ -112,6 +117,7 @@ for repo in "${repos[@]}"; do
     GH_COMMAND=$GH_COMMAND" -f \"description=${DESC}\""
   fi
 
+  # -- Create or update the milestone
   if [[ "$STATE" == "open" ]]; then
 
     if (( NUMBER )); then
@@ -125,7 +131,8 @@ for repo in "${repos[@]}"; do
       GH_COMMAND=$GH_COMMAND" /repos/${repo}/milestones"
       run_command "${GH_COMMAND}"
     fi
-    
+
+  # -- Close the milestone
   else
 
     if (( NUMBER )); then

From 6634e90c6ff26475972b8ddce5d55b2084d6408f Mon Sep 17 00:00:00 2001
From: jennyhickson <61183013+jennyhickson@users.noreply.github.com>
Date: Wed, 7 Jan 2026 13:45:12 +0000
Subject: [PATCH 3/4] fix lint issue

---
 sbin/gh_manage_milestones | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sbin/gh_manage_milestones b/sbin/gh_manage_milestones
index 7d25161..a5c647b 100755
--- a/sbin/gh_manage_milestones
+++ b/sbin/gh_manage_milestones
@@ -74,12 +74,12 @@ repos=(
 # -- Helper functions
 get_milestone_number(){
   local repo_name="$1"
-  gh api /repos/${repo_name}/milestones --jq ".[] | select(.title == \"${TITLE}\") | .number"
+  gh api /repos/"${repo_name}"/milestones --jq ".[] | select(.title == \"${TITLE}\") | .number"
 }
 
 check_exists(){
   local repo_name="$1"
-  gh api /repos/${repo_name}/milestones --jq ".[] | select(.title == \"${TITLE}\")"
+  gh api /repos/"${repo_name}"/milestones --jq ".[] | select(.title == \"${TITLE}\")"
 }
 
 run_command(){

From 569fd86e609e0056186b033998e6c84c533de6c4 Mon Sep 17 00:00:00 2001
From: jennyhickson <61183013+jennyhickson@users.noreply.github.com>
Date: Thu, 8 Jan 2026 15:06:06 +0000
Subject: [PATCH 4/4] refactor checking for existing milestones

---
 sbin/gh_manage_milestones | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/sbin/gh_manage_milestones b/sbin/gh_manage_milestones
index a5c647b..6a0a709 100755
--- a/sbin/gh_manage_milestones
+++ b/sbin/gh_manage_milestones
@@ -77,11 +77,6 @@ get_milestone_number(){
   gh api /repos/"${repo_name}"/milestones --jq ".[] | select(.title == \"${TITLE}\") | .number"
 }
 
-check_exists(){
-  local repo_name="$1"
-  gh api /repos/"${repo_name}"/milestones --jq ".[] | select(.title == \"${TITLE}\")"
-}
-
 run_command(){
   local gh_command="$1"
 
@@ -100,9 +95,8 @@ for repo in "${repos[@]}"; do
 
 
   # -- If milestone exists then fetch the number
-  NUMBER=0
-  if [[ $(check_exists "${repo}") ]]; then
-    NUMBER=$(get_milestone_number "${repo}")
+  NUMBER=$(get_milestone_number "${repo}")
+  if (( NUMBER )); then
     echo "${TITLE} in ${repo} is milestone ${NUMBER}"
   else
     echo "Milestone does not exist in ${repo}"