chore(ansible): dump newly discovered information

snippets/ansible/tasks/debug.yml

@@ -25,6 +25,7 @@
     var: install_method
 
 - name: Print all available variables
+  tags: print_all
   ansible.builtin.debug:
     var: vars  # magic variable
 
@@ -37,7 +38,9 @@
   ansible.builtin.shell: printenv | sort
 
 - name: Start the debugger on failure
-  tags: never
+  tags:
+    - never  # avoid execution unless explicitly requested with other tags
+    - debugger
   # print all variables at this point => p task_vars
   # continue => c
   # abort and quit => q

snippets/ansible/tasks/manipulate data.yml

@@ -319,3 +319,13 @@
     this_is_true_again: "{{ not false }}"
     true_is_truthy: "{{ true is truthy }}"
     false_is_falsy: "{{ false is falsy }}"
+
+- name: Undefined variables
+  tags: undefined_variable
+  # refer <https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_templating_undef.html>
+  # only works for variables of lesser priority
+  # e.g., works in tasks' `vars:`, but not in the `set_facts` module to (re)define a variable
+  vars:
+    test_var: "{{ undef() }}"
+  ansible.builtin.debug:
+    var: test_var

snippets/ansible/use tasks from other files.yml

@@ -8,11 +8,23 @@
   connection: local
   gather_facts: false
   tasks:
-    - ansible.builtin.import_tasks: tasks/debug.yml
-    - ansible.builtin.import_tasks:
+    - name: Import tasks in-line
+      ansible.builtin.import_tasks: tasks/debug.yml
+    - name: Import tasks with arguments and set variables for them
+      vars:
+        somevar: some value
+      ansible.builtin.import_tasks:
         file: tasks/control flows.yml
-    - ansible.builtin.include_tasks: tasks/manipulate data.yml
-    - ansible.builtin.include_tasks:
+    - name: Include tasks in-line
+      tags: always
+      ansible.builtin.include_tasks: tasks/manipulate data.yml
+    - name: Include tasks with arguments and set variables for them
+      tags: always
+      vars:
+        somevar: some value
+      ansible.builtin.include_tasks:
         file: tasks/manipulate data.yml
         apply:
           tags: data_manipulation
+          vars:
+            someothervar: some other value