Introduce 'changed_when' keyword to override a task's changed status with the evaluation of a Jinja2 expression

test/playbook-changed_when.yml

@@ -0,0 +1,25 @@
+---
+- hosts: all
+  connection: local
+  gather_facts: False
+
+  tasks:
+  - action: command echo first action
+  - action: command echo second action
+    register: var
+    changed_when: "'X' in var.stdout"
+  - action: shell exit 2
+    register: exit
+    ignore_errors: yes
+    changed_when: "exit.rc < 1"
+  - action: command echo third action
+    changed_when: false
+  - action: file path=/ state=directory
+    changed_when: true
+  - action: command echo {{item}}
+    register: out
+    changed_when: "'e' in out.stdout"
+    with_items:
+      - hello
+      - foo
+      - bye