Fix alternatives module (#4836)

* Only pass subcommands when they are specified as module arguments.

* When 'subcommands' is specified, 'link' must be given for every subcommand.

* Extend subcommand tests.

changelogs/fragments/4836-alternatives.yml

@@ -0,0 +1,3 @@
+bugfixes:
+  - "alternatives - only pass subcommands when they are specified as module arguments (https://github.com/ansible-collections/community.general/issues/4803, https://github.com/ansible-collections/community.general/issues/4804, https://github.com/ansible-collections/community.general/pull/4836)."
+  - "alternatives - when ``subcommands`` is specified, ``link`` must be given for every subcommand. This was already mentioned in the documentation, but not enforced by the code (https://github.com/ansible-collections/community.general/pull/4836)."

plugins/modules/system/alternatives.py

@@ -77,6 +77,7 @@ options:
         description:
           - The path to the symbolic link that should point to the real subcommand executable.
         type: path
+        required: true
     version_added: 5.1.0
 requirements: [ update-alternatives ]
 '''
@@ -204,7 +205,7 @@ class AlternativesModule(object):
 
         cmd = [self.UPDATE_ALTERNATIVES, '--install', self.link, self.name, self.path, str(self.priority)]
 
-        if self.subcommands is not None:
+        if self.module.params['subcommands'] is not None:
             subcommands = [['--slave', subcmd['link'], subcmd['name'], subcmd['path']] for subcmd in self.subcommands]
             cmd += [item for sublist in subcommands for item in sublist]
 
@@ -384,7 +385,7 @@ def main():
             subcommands=dict(type='list', elements='dict', aliases=['slaves'], options=dict(
                 name=dict(type='str', required=True),
                 path=dict(type='path', required=True),
-                link=dict(type='path'),
+                link=dict(type='path', required=True),
             )),
         ),
         supports_check_mode=True,

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

@@ -66,6 +66,8 @@
         state: absent
       with_items:
         - '{{ alternatives_dir }}/dummy'
+        - '{{ alternatives_dir }}/dummymain'
+        - '{{ alternatives_dir }}/dummysubcmd'
 
     - file:
         path: '/usr/bin/dummy{{ item }}'

tests/integration/targets/alternatives/tasks/subcommands.yml

@@ -32,6 +32,15 @@
     that:
       - cmd.stdout == "dummy2"
 
+- name: Get dummymain alternatives output
+  command:
+    cmd: '{{ alternatives_command }} --display dummymain'
+  register: result
+
+- name: Print result
+  debug:
+    var: result.stdout_lines
+
 - name: Subcommands are not removed if not specified
   alternatives:
     name: dummymain
@@ -76,3 +85,133 @@
     that:
       - cmd.rc == 2
       - '"No such file" in cmd.msg'
+
+- name: Get dummymain alternatives output
+  command:
+    cmd: '{{ alternatives_command }} --display dummymain'
+  register: result
+
+- name: Print result
+  debug:
+    var: result.stdout_lines
+
+- name: Install other alternative with subcommands
+  alternatives:
+    name: dummymain
+    path: '/usr/bin/dummy3'
+    link: '/usr/bin/dummymain'
+    subcommands:
+      - name: dummysubcmd
+        path: '/usr/bin/dummy4'
+        link: '/usr/bin/dummysubcmd'
+  register: alternative
+
+- name: Check expected command was executed
+  assert:
+    that:
+      - 'alternative is changed'
+
+- name: Execute the current dummymain command
+  command: dummymain
+  register: cmd
+
+- name: Ensure that the expected command was executed
+  assert:
+    that:
+      - cmd.stdout == "dummy3"
+
+- name: Execute the current dummysubcmd command
+  command: dummysubcmd
+  register: cmd
+
+- name: Ensure that the expected command was executed
+  assert:
+    that:
+      - cmd.stdout == "dummy4"
+
+- name: Get dummymain alternatives output
+  command:
+    cmd: '{{ alternatives_command }} --display dummymain'
+  register: result
+
+- name: Print result
+  debug:
+    var: result.stdout_lines
+
+- name: Switch to first alternative
+  alternatives:
+    name: dummymain
+    path: '/usr/bin/dummy1'
+  register: alternative
+
+- name: Check expected command was executed
+  assert:
+    that:
+      - 'alternative is changed'
+
+- name: Execute the current dummymain command
+  command: dummymain
+  register: cmd
+
+- name: Ensure that the expected command was executed
+  assert:
+    that:
+      - cmd.stdout == "dummy1"
+
+- name: Execute the current dummysubcmd command
+  command: dummysubcmd
+  register: cmd
+  ignore_errors: True
+
+- name: Ensure that the subcommand is gone
+  assert:
+    that:
+      - cmd.rc == 2
+      - '"No such file" in cmd.msg'
+
+- name: Get dummymain alternatives output
+  command:
+    cmd: '{{ alternatives_command }} --display dummymain'
+  register: result
+
+- name: Print result
+  debug:
+    var: result.stdout_lines
+
+- name: Switch to second alternative
+  alternatives:
+    name: dummymain
+    path: '/usr/bin/dummy3'
+  register: alternative
+
+- name: Check expected command was executed
+  assert:
+    that:
+      - 'alternative is changed'
+
+- name: Execute the current dummymain command
+  command: dummymain
+  register: cmd
+
+- name: Ensure that the expected command was executed
+  assert:
+    that:
+      - cmd.stdout == "dummy3"
+
+- name: Execute the current dummysubcmd command
+  command: dummysubcmd
+  register: cmd
+
+- name: Ensure that the expected command was executed
+  assert:
+    that:
+      - cmd.stdout == "dummy4"
+
+- name: Get dummymain alternatives output
+  command:
+    cmd: '{{ alternatives_command }} --display dummymain'
+  register: result
+
+- name: Print result
+  debug:
+    var: result.stdout_lines

tests/integration/targets/alternatives/vars/Debian.yml

@@ -1,2 +1,3 @@
 ---
 alternatives_dir: /var/lib/dpkg/alternatives/
+alternatives_command: update-alternatives

tests/integration/targets/alternatives/vars/Suse-42.3.yml

@@ -1,2 +1,3 @@
 ---
 alternatives_dir: /var/lib/rpm/alternatives/
+alternatives_command: update-alternatives

tests/integration/targets/alternatives/vars/default.yml

@@ -1,2 +1,3 @@
 ---
 alternatives_dir: /var/lib/alternatives/
+alternatives_command: update-alternatives