Prevent closure parent incident when child incidents open (#1750)

* Create scriptBR.js

* Create README.md

* Update scriptBR.js

* Update README.md

* Update README.md

Author: naveensnow

Server-Side Components/Business Rules/Abort Parent Incident Closure When Child is Open/README.md

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+This business rule is designed for ServiceNow to prevent a parent incident from being closed or resolved while it still has active child incidents.
+If a user attempts to set the parent incident's state to "Resolved," "Closed," or "Cancelled," the rule will query for any related child incidents that are still open. 
+If open children are found, the update will be aborted, and an error message will be displayed to the user.
+
+Navigate to System Definition > Business Rules in the ServiceNow filter navigator.
+Click New.
+Fill out the form with the following details:
+Name: Prevent Parent Closure with Open Children
+Table: Incident [incident]
+Advanced: true
+When: before
+Update: Check this box.
+In the When to run tab, set the Condition field:
+current.state.changesTo(7) || current.state.changesTo(6) || current.state.changesTo(8)  //The state values are: 6 (Resolved), 7 (Closed), 8 (Cancelled).
+Note: The state values (6, 7, 8) may vary based on your instance configuration.
+In the Advanced tab, paste the provided script into the Script field.

Server-Side Components/Business Rules/Abort Parent Incident Closure When Child is Open/scriptBR.js

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+(function executeRule(current, previous /*null when async*/) {
+    
+    
+    //When the Incident state values are set to: 6 (Resolved), 7 (Closed), 8 (Cancelled).
+    // The `previous.state` check prevents the script from running when a closed ticket is re-closed.
+    if ((current.state == '6' || current.state == '7' || current.state == '8') && current.state != previous.state) {
+
+        // Use GlideAggregate to efficiently count child incidents that are not yet closed.
+        var ga = new GlideAggregate('incident');
+        ga.addQuery('parent_incident', current.sys_id);
+        ga.addActiveQuery();
+        ga.addAggregate('COUNT');
+        ga.query();
+        var childCount = 0;
+        if (ga.next()) {
+            // Retrieve the aggregated count.
+            childCount = ga.getAggregate('COUNT');
+        }
+        // If open child incidents are found, abort the parent's closure and display an error.
+        if (childCount > 0) {
+            gs.addErrorMessage('Cannot close this incident. ' + childCount + ' child incidents are still open.');
+            current.setAbortAction(true);
+        }
+    }
+
+})(current, previous);