apt_repository: Do not convert symlink repo to a normal file (#82271)

* apt_repository: Do not convert symlink repo to a normal file

* module manually writes to repo files. If the file is a symlink
  module used to re-write and convert a symlink to a normal file.
  This fix tracks the symlink and keeps the changes intact.

Fixes: #49809

Signed-off-by: Abhijeet Kasurde <akasurde@redhat.com>

changelogs/fragments/49809_apt_repository.yml

@@ -0,0 +1,3 @@
+---
+bugfixes:
+- apt_repository - do not modify repo files if the file is a symlink (https://github.com/ansible/ansible/issues/49809).

lib/ansible/modules/apt_repository.py

@@ -230,6 +230,7 @@ class SourcesList(object):
     def __init__(self, module):
         self.module = module
         self.files = {}  # group sources by file
+        self.files_mapping = {}  # internal DS for tracking symlinks
         # Repositories that we're adding -- used to implement mode param
         self.new_repos = set()
         self.default_file = self._apt_cfg_file('Dir::Etc::sourcelist')
@@ -240,6 +241,8 @@ class SourcesList(object):
 
         # read sources.list.d
         for file in glob.iglob('%s/*.list' % self._apt_cfg_dir('Dir::Etc::sourceparts')):
+            if os.path.islink(file):
+                self.files_mapping[file] = os.readlink(file)
             self.load(file)
 
     def __iter__(self):
@@ -372,7 +375,11 @@ class SourcesList(object):
                         f.write(line)
                     except IOError as ex:
                         self.module.fail_json(msg="Failed to write to file %s: %s" % (tmp_path, to_native(ex)))
-                self.module.atomic_move(tmp_path, filename)
+                if filename in self.files_mapping:
+                    # Write to symlink target instead of replacing symlink as a normal file
+                    self.module.atomic_move(tmp_path, self.files_mapping[filename])
+                else:
+                    self.module.atomic_move(tmp_path, filename)
 
                 # allow the user to override the default mode
                 if filename in self.new_repos:
@@ -417,7 +424,7 @@ class SourcesList(object):
     def _add_valid_source(self, source_new, comment_new, file):
         # We'll try to reuse disabled source if we have it.
         # If we have more than one entry, we will enable them all - no advanced logic, remember.
-        self.module.log('ading source file: %s | %s | %s' % (source_new, comment_new, file))
+        self.module.log('adding source file: %s | %s | %s' % (source_new, comment_new, file))
         found = False
         for filename, n, enabled, source, comment in self:
             if source == source_new:

test/integration/targets/apt_repository/tasks/apt.yml

@@ -253,6 +253,46 @@
       - result is failed
       - result.msg == 'Please set argument \'repo\' to a non-empty value'
 
+#
+# TEST: keep symlink
+#
+- import_tasks: 'cleanup.yml'
+
+- name: install local-apt-repository with apt
+  apt: pkg=local-apt-repository state=present
+
+- name: Check if local apt repo file is a symlink
+  stat:
+    path: /etc/apt/sources.list.d/local-apt-repository.list
+  register: stat_result
+
+- name: Assert if local apt repo file is a symlink 
+  assert:
+    that:
+      - stat_result.stat.islnk is defined and stat_result.stat.islnk
+      - stat_result.stat.lnk_source == "/usr/lib/local-apt-repository/local-apt-repository.list"
+
+- name: Try installing an invalid repo 
+  apt_repository:
+    repo: deb http://dl.google.com/linux/chrome/deb2/ stable main
+    state: present
+    filename: google-chrome
+  ignore_errors: true
+
+- name: Check the stat for the given symlink
+  stat:
+    path: /etc/apt/sources.list.d/local-apt-repository.list
+  register: stat_result2
+
+- name: Assert that the symlink is intact after apt_repository operation
+  assert:
+    that:
+      - stat_result2.stat.islnk is defined and stat_result2.stat.islnk
+      - stat_result2.stat.lnk_source == "/usr/lib/local-apt-repository/local-apt-repository.list"  
+
+- name: uninstall local-apt-repository with apt
+  apt: pkg=local-apt-repository state=absent purge=yes
+
 #
 # TEARDOWN
 #