mount - add a newline at the end of line in fstab

* Fixes #210

Signed-off-by: Hideki Saito <saito@fgrep.org>

changelogs/fragments/211_fstab_append_newline.yml

@@ -0,0 +1,3 @@
+---
+bugfixes:
+- mount - add a newline at the end of line in ``fstab`` (https://github.com/ansible-collections/ansible.posix/issues/210).

plugins/modules/mount.py

@@ -254,6 +254,10 @@ def _set_mount_save_old(module, args):
             '%(src)s - %(name)s %(fstype)s %(passno)s %(boot)s %(opts)s\n')
 
     for line in open(args['fstab'], 'r').readlines():
+        # Append newline if the line in fstab does not finished with newline.
+        if not line.endswith('\n'):
+            line += '\n'
+
         old_lines.append(line)
 
         if not line.strip():

tests/integration/targets/mount/tasks/main.yml

@@ -369,3 +369,40 @@
     - /tmp/myfs.img
     - /tmp/myfs
   when: ansible_system in ('Linux')
+
+- name: Block to test missing newline at the EOF of fstab
+  block:
+  - name: Create empty file
+    community.general.filesize:
+      path: /tmp/myfs1.img
+      size: 20M
+  - name: Format FS
+    community.general.filesystem:
+      fstype: ext3
+      dev: /tmp/myfs1.img
+  - name: Create custom fstab file without newline
+    copy:
+      content: '#TEST COMMENT WITHOUT NEWLINE'
+      dest: /tmp/test_fstab
+  - name: Mount the FS using the custom fstab
+    mount:
+      path: /tmp/myfs1
+      src: /tmp/myfs1.img
+      fstype: ext3
+      state: mounted
+      opts: defaults
+      fstab: /tmp/test_fstab
+  - name: Unmount the mount point in the custom fstab
+    mount:
+      path: /tmp/myfs1
+      state: absent
+      fstab: /tmp/test_fstab
+  - name: Remove the test FS and the custom fstab
+    file:
+      path: '{{ item }}'
+      state: absent
+    loop:
+    - /tmp/myfs1.img
+    - /tmp/myfs1
+    - /tmp/test_fstab
+  when: ansible_system in ('Linux')