[WIP] Create preserved_copy function in basic.py to perserve file ownership. (#27344)

Create preserved_copy function in basic.py to perserve file ownership.

* Add a test for template preserved backup
* Use a script to get the random names
* bytes to strings
* Remove dump of hostvars
* Stop being fancy and create a testuser instead
* Fix pep8
* set file attributes
* Pass the correct data to set_attributes_if_different
* Use -j instead -b and pass the attributes as a string instead of a list
* remove debugging message
* Use shell to softly set the attr

Fixes #24408

test/integration/targets/template/tasks/backup_test.yml

@@ -0,0 +1,60 @@
+# https://github.com/ansible/ansible/issues/24408
+
+- set_fact:
+    t_username: templateuser1
+    t_groupname: templateuser1
+
+- name: create the test group
+  group:
+    name: "{{ t_groupname }}"
+
+- name: create the test user
+  user:
+    name: "{{ t_username }}"
+    group: "{{ t_groupname }}"
+    createhome: no
+
+- name: set the dest file
+  set_fact:
+      t_dest: "{{ output_dir + '/tfile_dest.txt' }}"
+
+- name: create the old file
+  file:
+    path: "{{ t_dest }}"
+    state: touch
+    mode: 0777
+    owner: "{{ t_username }}"
+    group: "{{ t_groupname }}"
+
+- name: failsafe attr change incase underlying system does not support it
+  shell: chattr =j "{{ t_dest }}"
+  ignore_errors: True
+
+- name: run the template
+  template:
+    src: foo.j2
+    dest: "{{ t_dest }}"
+    backup: True
+  register: t_backup_res
+
+- name: check the data for the backup
+  stat:
+    path: "{{ t_backup_res.backup_file }}"
+  register: t_backup_stats
+
+- name: validate result of preserved backup
+  assert:
+      that:
+          - 't_backup_stats.stat.mode == "0777"'
+          - 't_backup_stats.stat.pw_name == t_username'
+          - 't_backup_stats.stat.gr_name == t_groupname'
+
+- name: cleanup the user
+  user:
+    name: "{{ t_username }}"
+    state: absent
+
+- name: cleanup the group
+  user:
+    name: "{{ t_groupname }}"
+    state: absent

test/integration/targets/template/tasks/main.yml

@@ -369,3 +369,6 @@
     that:
         - 'diff_result.stdout == ""'
         - "diff_result.rc == 0"
+
+# aliases file requires root for template tests so this should be safe
+- include: backup_test.yml