Adding error suggestion to generic error while copying GDG if its in edit mode.

changelogs/fragments/2220-zos_copy-better-error-message-GDG-copy-issue.yml

@@ -0,0 +1,4 @@
+minor_changes:
+   - zos_copy - Adds a better error message that gives user a
+     hint that copy issue can be due to 'src' GDG in edit state.
+     (https://github.com/ansible-collections/ibm_zos_core/pull/2220)

plugins/modules/zos_copy.py

@@ -1205,9 +1205,20 @@ def copy_to_gdg(self, src, dest):
                 # If identical_gdg_copy is False, use the default next generation
                 dest_gen_name = f"{dest}(+1)"
                 # Perform the copy operation
-            rc = datasets.copy(gds.name, dest_gen_name, **copy_args)
-            if rc != 0:
-                success = False
+
+            try:
+                result = datasets.copy(gds.name, dest_gen_name, **copy_args)
+                rc = result.rc if hasattr(result, 'rc') else result
+                if rc != 0:
+                    success = False
+            except zoau_exceptions.ZOAUException as e:
+                stderr = getattr(e.response, 'stderr_response', str(e))
+                if "BGYSC6003E" in stderr :
+                    raise GenerationDataGroupCreateError(
+                        msg="BGYSC6003E  Invalid generation relative name: This might be because the src GDG is in open state"
+                    ) from e
+                else:
+                    raise GenerationDataGroupCreateError(msg=f"GDG creation failed. Raw error: {stderr}") from e
         return success
 
     def _copy_tree(self, entries, src, dest, dirs_exist_ok=False):
@@ -4343,5 +4354,12 @@ def __init__(
         super().__init__(msg)
 
 
+class GenerationDataGroupCreateError(Exception):
+    def __init__(self, msg):
+        """Error during copy of a Generation Data Group."""
+        self.msg = msg
+        super().__init__(self.msg)
+
+
 if __name__ == "__main__":
     main()