accept + and - modifiers for file attributes (#40061)

* accept + and - modifiers for file attributes
* tests for adding/removing file attributes

lib/ansible/module_utils/basic.py

@@ -1355,10 +1355,15 @@ class AnsibleModule(object):
 
         existing = self.get_file_attributes(b_path)
 
-        if existing.get('attr_flags', '') != attributes:
+        attr_mod = '='
+        if attributes.startswith(('-', '+')):
+            attr_mod = attributes[0]
+            attributes = attributes[1:]
+
+        if existing.get('attr_flags', '') != attributes or attr_mod == '-':
             attrcmd = self.get_bin_path('chattr')
             if attrcmd:
-                attrcmd = [attrcmd, '=%s' % attributes, b_path]
+                attrcmd = [attrcmd, '%s%s' % (attr_mod, attributes), b_path]
                 changed = True
 
                 if diff is not None:
@@ -1367,7 +1372,7 @@ class AnsibleModule(object):
                     diff['before']['attributes'] = existing.get('attr_flags')
                     if 'after' not in diff:
                         diff['after'] = {}
-                    diff['after']['attributes'] = attributes
+                    diff['after']['attributes'] = '%s%s' % (attr_mod, attributes)
 
                 if not self.check_mode:
                     try:

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

@@ -82,13 +82,13 @@
       - "file4_result.changed == true"
       - "file4_result.mode == '0600'"
 
-- name: change file attribute "A"
+- name: explicitly set file attribute "A"
   file: path={{output_dir}}/baz.txt attributes=A
   register: file_attributes_result
   ignore_errors: True
 
-- name: reapply file attribute "A"
+- name: add file attribute "A"
-  file: path={{output_dir}}/baz.txt attributes=A
+  file: path={{output_dir}}/baz.txt attributes=+A
   register: file_attributes_result_2
   when: file_attributes_result is changed
 
@@ -98,6 +98,22 @@
       - "file_attributes_result_2 is not changed"
   when: file_attributes_result is changed
 
+- name: remove file attribute "A"
+  file: path={{output_dir}}/baz.txt attributes=-A
+  register: file_attributes_result_3
+  ignore_errors: True
+
+- name: explicitly remove file attributes
+  file: path={{output_dir}}/baz.txt attributes=""
+  register: file_attributes_result_4
+  when: file_attributes_result_3 is changed
+
+- name: verify that the file was not marked as changed
+  assert:
+    that:
+      - "file_attributes_result_4 is not changed"
+  when: file_attributes_result_4 is changed
+
 - name: change ownership and group
   file: path={{output_dir}}/baz.txt owner=1234 group=1234