cloudwatchevent_rule should return false when there is no change done to the rule

changelogs/fragments/1589-return_false_when_no_change..yml

@@ -0,0 +1,3 @@
+---
+bugfixes:
+- cloudwatchevent_rule - add scrub none inside the _targets_to_put method (https://github.com/ansible-collections/amazon.aws/pull/1589)."

plugins/modules/cloudwatchevent_rule.py

@@ -433,6 +433,18 @@ def _rule_matches_aws(self):
     def _targets_to_put(self):
         """Returns a list of targets that need to be updated or added remotely"""
         remote_targets = self.rule.list_targets()
+
+        # keys with none values must be scrubbed off of self.targets
+        temp = []
+        for t in self.targets:
+            if t["input_transformer"] is not None and t["input_transformer"]["input_template"] is not None:
+                # The remote_targets contain quotes, so add
+                # quotes to temp
+                val = t["input_transformer"]["input_template"]
+                t["input_transformer"]["input_template"] = '"' + val + '"'
+            temp.append(scrub_none_parameters(t))
+        self.targets = temp
+
         return [t for t in self.targets if t not in remote_targets]
 
     def _remote_target_ids_to_remove(self):

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

@@ -52,6 +52,27 @@
         that:
           - event_rule_input_transformer_output.changed
 
+    - name: Create cloudwatch event rule with input transformer (idempotent)
+      cloudwatchevent_rule:
+        name: "{{ input_transformer_event_name }}"
+        description: "Event rule with input transformer configuration"
+        state: present
+        event_pattern: '{"source":["aws.ec2"],"detail-type":["EC2 Instance State-change Notification"],"detail":{"state":["pending"]}}'
+        targets:
+          - id: "{{ sns_topic_output.sns_topic.name }}"
+            arn: "{{ sns_topic_output.sns_topic.topic_arn }}"
+            input_transformer:
+              input_paths_map:
+                instance: "$.detail.instance-id"
+                state: "$.detail.state"
+              input_template: "<instance> is in state <state>"
+      register: event_rule_input_transformer_output
+
+    - name: Assert that no changes were made to the rule
+      assert:
+        that:
+          - event_rule_input_transformer_output is not changed
+
     - name: Create cloudwatch event rule with inputs
       cloudwatchevent_rule:
         name: "{{ input_event_name }}"