main_v5.1 - Enhance update truth data workflow to create a uniquely n…

…amed branch... (#2678)

* Enhance update truth data workflow to create a uniquely named branch to update *-ref branches and commit/append to a log file that tracks the reasons for updating the truth data. This is done to ensure that the *-ref branch testing workflow run that actually updates the truth data is always run even if there are no other changes to the METplus branch since the last update, e.g. when a change to another component like MET warrants the truth data update

* git add change log file in case it doesn't already exist

* changed logic to no longer push changes to develop/main_vX.Y, but instead merge changes from -ref into the update branch

* retain update truth history file from *-ref

.github/workflows/update_truth.yml

@@ -12,7 +12,7 @@ on:
 
 jobs:
   update_truth:
-    name: "Update or create truth reference branch"
+    name: "Update truth reference branch"
     runs-on: ubuntu-latest
     steps:
       - name: Check if branch is develop or main_vX.Y
@@ -32,6 +32,7 @@ jobs:
           fetch-depth: 0
           token: ${{ secrets.METPLUS_BOT_TOKEN }}
       - name: Resolve conflicts between branch and branch-ref
+        id: resolve_conflicts
         run: |
           branch_name=${{ env.branch_name }}
           cd ${GITHUB_WORKSPACE}
@@ -43,17 +44,54 @@ jobs:
           echo ${branch_name}-ref does exist -- update it
           git config --global user.name "metplus-bot"
           git config --global user.email "[email protected]"
+          # checkout branch (develop or main_vX.Y)
           echo git checkout ${branch_name}
           git checkout ${branch_name}
+
+          # create unique branch name to update *-ref branch
+          update_branch=update_${branch_name}_$(uuidgen | cut -d "-" -f1)
+          echo "update_branch=${update_branch}" >> $GITHUB_OUTPUT
+
+          # create update branch from branch (develop or main_vX.Y)
+          echo git checkout -b ${update_branch}
+          git checkout -b ${update_branch}
+
+          # merge -ref branch into update branch (favoring branch changes)
           echo git merge -s ours origin/${branch_name}-ref
           git merge -s ours origin/${branch_name}-ref
-          echo git push origin ${branch_name}
-          git push origin ${branch_name}
 
+          change_log_path=.github/update_truth_change_log.txt
+
+          # get truth change log from *-ref branch
+          cmd="git checkout origin/${branch_name}-ref -- ${change_log_path}"
+          echo $cmd
+          $cmd
+
+          # create or append to file to track truth data changes
+          # and ensure that PR merge into *-ref branch triggered testing workflow
+          change_entry="[$(date +%Y%m%d_%H:%M:%S) ${branch_name}] ${{ github.event.inputs.pull_requests }} - ${{ github.event.inputs.change_summary }}"
+          echo "${change_entry}" >> ${change_log_path}
+
+          # add file if it does not already exist
+          cmd="git add ${change_log_path}"
+          echo $cmd
+          $cmd
+
+          # commit changes to change log file
+          echo git commit ${change_log_path}
+          git commit -m "added entry to update truth change log: ${branch_name} ${{ github.event.inputs.pull_requests }}" ${change_log_path}
+
+          # push changes to update branch on GitHub
+          cmd="git push origin ${update_branch}"
+          echo $cmd
+          $cmd
+
+      # create pull request from $HEAD into $BASE
       - name: Create Pull Request
-        run: gh pr create --base $BASE --body "$BODY" --title "$TITLE"
+        run: gh pr create --head $HEAD --base $BASE --body "$BODY" --title "$TITLE"
         env:
           GH_TOKEN: ${{ github.token }}
+          HEAD: ${{ steps.resolve_conflicts.outputs.update_branch }}
           BASE: ${{ env.branch_name }}-ref
           BODY: ${{ github.event.inputs.change_summary }}<br/>Created by @${{ github.actor}}
           TITLE: Update ${{ env.branch_name }}-ref after ${{ github.event.inputs.pull_requests }}