[develop] Add logic to assert that the output of the diff command must do not contain lines starting with "Only in /tmp/home"

cookbooks/aws-parallelcluster-environment/recipes/init/restore_home_shared_data.rb

@@ -18,19 +18,65 @@
   # Restore the shared storage home data if it doesn't already exist
   # This is necessary to preserve any data in these directories that was
   # generated during the build of ParallelCluster AMIs after converting to
-  # shared storage and backed up to a temporary location previously
+  # shared storage and backed up to a temporary location previously.
   # Before removing the backup, ensure the data in the new home is the same
   # as the original to avoid any data loss or inconsistency. This is done
   # by using rsync to copy the data and diff to check for differences.
+  # The diff command excludes files that were originally in /home to focus on
+  # the newly synchronized files. This approach is necessary because the /home
+  # directory may contain pre-existing files such as slurm-*.out generated by
+  # running SLURM jobs and the automatically created lost+found directory.
   # Remove the backup after the copy is done and the data integrity is verified.
   bash "Restore /home" do
     user 'root'
     group 'root'
     code <<-EOH
+      # Generate a list of existing files and dirs in /home before the sync
+      find /home -mindepth 1 > /tmp/home_existing_files.txt
+
+      # Initialize an empty set for exclude options and directories to exclude
+      exclude_options=""
+      declare -A exclude_dirs
+
+      # Process each file in the list
+      while IFS= read -r file; do
+        # Remove the /home/ prefix
+        relative_path=${file#/home/}
+
+        # Initialize current path
+        current_path="/tmp/home"
+
+        # Split the relative path by /
+        IFS='/' read -ra parts <<< "$relative_path"
+
+        for part in "${parts[@]}"; do
+          current_path="$current_path/$part"
+          if [ ! -e "$current_path" ]; then
+            # If the path does not exist in /tmp/home, add the last part of path to the exclude list
+            if [ -z "${exclude_dirs[$part]}" ]; then
+              exclude_dirs[$part]=1
+              exclude_options="$exclude_options --exclude=$part"
+            fi
+            break
+          else
+            if [ -f "$current_path" ]; then
+              # If the path is a file, add it to the exclude list
+              exclude_options="$exclude_options --exclude=$part"
+              break
+            fi
+            # If the path is a directory, continue checking subdirectories
+          fi
+        done
+      done < /tmp/home_existing_files.txt
+
+      # Sync data from /tmp/home to /home
       rsync -a --ignore-existing /tmp/home/ /home
-      diff_output=$(diff -r /tmp/home/ /home)
+
+      # Perform the diff check, excluding the original files
+      diff_output=$(eval diff -r $exclude_options /tmp/home /home)
       if [ $? -eq 0 ]; then
         rm -rf /tmp/home/
+        rm -rf /tmp/home_existing_files.txt
       else
         echo "Data integrity check failed comparing /home and /tmp/home: $diff_output"
         exit 1