Bulk-safe request processing with per-request error isolation

README.md

@@ -19,6 +19,8 @@ If the record collection is null, empty, or the field value is null, the respons
 - Works with **any SObject**
 - Field selection via **dynamic Field API Name**
 - Null-safe for records and field values
+- Bulk-safe: each request is processed independently — one invalid field name or bad request does not fail others
+- Per-request error reporting via the `errorMessage` output variable
 - No DML or SOQL
 - Uses `with sharing` to respect org security
 
@@ -36,8 +38,10 @@ If the record collection is null, empty, or the field value is null, the respons
 ## Behavior Notes
 
 - The first record is determined by the **existing collection order**
-- No sorting or validation of the field API name is performed
-- If the field does not exist or the value is null, the response is `null`
+- If `fieldApiName` is blank, `response` is `null` and `errorMessage` is populated
+- If the field does not exist on the SObject, `response` is `null` and `errorMessage` contains the exception detail
+- If the field value is `null`, `response` is `null` and `errorMessage` is also `null`
 - All returned values are converted to **String**
+- When multiple requests are passed (bulk invocation), each is processed independently so that one failing request does not affect the others
 
 ---

force-app/main/default/classes/CollectionGetFirstValue_Records.cls

@@ -13,10 +13,22 @@ public with sharing class CollectionGetFirstValue_Records {
                 continue;
             }
 
-            SObject firstRecord = req.records[0];
-            Object fieldValue = firstRecord.get(req.fieldApiName);
+            if (String.isBlank(req.fieldApiName)) {
+                resp.response = null;
+                resp.errorMessage = 'The fieldApiName parameter is required and cannot be blank.';
+                results.add(resp);
+                continue;
+            }
+
+            try {
+                SObject firstRecord = req.records[0];
+                Object fieldValue = firstRecord.get(req.fieldApiName);
+                resp.response = (fieldValue == null) ? null : String.valueOf(fieldValue);
+            } catch (SObjectException e) {
+                resp.response = null;
+                resp.errorMessage = e.getMessage();
+            }
 
-            resp.response = (fieldValue == null) ? null : String.valueOf(fieldValue);
             results.add(resp);
         }
 
@@ -34,5 +46,8 @@ public with sharing class CollectionGetFirstValue_Records {
     public class Response {
         @InvocableVariable(label='Response' description='Single text response containing the first field value')
         public String response;
+
+        @InvocableVariable(label='Error Message' description='Contains error details if the field value could not be retrieved; null when successful.')
+        public String errorMessage;
     }
 }

force-app/main/default/classes/CollectionGetFirstValue_RecordsTest.cls

@@ -49,4 +49,55 @@ public with sharing class CollectionGetFirstValue_RecordsTest {
         System.assertEquals(null, responses[0].response, 'Null records should result in null response');
     }
 
+    @IsTest
+    static void testGetFirstValue_BlankFieldApiName() {
+        Account a = new Account(Name = 'Test Account');
+
+        CollectionGetFirstValue_Records.Request req = new CollectionGetFirstValue_Records.Request();
+        req.records = new List<SObject>{ a };
+        req.fieldApiName = '';
+
+        List<CollectionGetFirstValue_Records.Request> requests = new List<CollectionGetFirstValue_Records.Request>{ req };
+
+        List<CollectionGetFirstValue_Records.Response> responses = CollectionGetFirstValue_Records.getFirstValue(requests);
+
+        System.assertEquals(1, responses.size());
+        System.assertEquals(null, responses[0].response, 'Blank fieldApiName should result in null response');
+        System.assertNotEquals(null, responses[0].errorMessage, 'Blank fieldApiName should populate errorMessage');
+    }
+
+    @IsTest
+    static void testGetFirstValue_InvalidFieldApiName_DoesNotBreakBatch() {
+        Account testAccount = new Account(Name = 'Good Account');
+
+        // Request 1: valid field
+        CollectionGetFirstValue_Records.Request reqGood = new CollectionGetFirstValue_Records.Request();
+        reqGood.records = new List<SObject>{ testAccount };
+        reqGood.fieldApiName = 'Name';
+
+        // Request 2: invalid field — should not cause Request 1 or 3 to fail
+        CollectionGetFirstValue_Records.Request reqBad = new CollectionGetFirstValue_Records.Request();
+        reqBad.records = new List<SObject>{ testAccount };
+        reqBad.fieldApiName = 'NonExistentField__xyz';
+
+        // Request 3: another valid field
+        CollectionGetFirstValue_Records.Request reqGood2 = new CollectionGetFirstValue_Records.Request();
+        reqGood2.records = new List<SObject>{ testAccount };
+        reqGood2.fieldApiName = 'Name';
+
+        List<CollectionGetFirstValue_Records.Request> requests = new List<CollectionGetFirstValue_Records.Request>{ reqGood, reqBad, reqGood2 };
+
+        Test.startTest();
+        List<CollectionGetFirstValue_Records.Response> responses = CollectionGetFirstValue_Records.getFirstValue(requests);
+        Test.stopTest();
+
+        System.assertEquals(3, responses.size(), 'Should return a response for each request even when one has an invalid field');
+        System.assertEquals('Good Account', responses[0].response, 'Valid request before the bad one should succeed');
+        System.assertEquals(null, responses[0].errorMessage, 'Valid request should have no error');
+        System.assertEquals(null, responses[1].response, 'Invalid field should result in null response');
+        System.assertNotEquals(null, responses[1].errorMessage, 'Invalid field should populate errorMessage');
+        System.assertEquals('Good Account', responses[2].response, 'Valid request after the bad one should succeed');
+        System.assertEquals(null, responses[2].errorMessage, 'Valid request should have no error');
+    }
+
 }