revert loop back, and address feedback

Author: geruh

core/src/main/java/org/apache/iceberg/rest/CatalogHandlers.java

@@ -26,7 +26,6 @@
 import java.time.OffsetDateTime;
 import java.time.ZoneOffset;
 import java.util.Collections;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
@@ -780,37 +779,31 @@ private static Pair<List<FileScanTask>, String> planFilesFor(
       TableScan tableScan, String planId, int tasksPerPlanTask) {
     Iterable<List<FileScanTask>> taskGroupings =
         Iterables.partition(tableScan.planFiles(), tasksPerPlanTask);
-    Iterator<List<FileScanTask>> taskIterator = taskGroupings.iterator();
-    String planTaskKeyPrefix = planId + "-" + tableScan.table().uuid() + "-";
-
-    if (!taskIterator.hasNext()) {
-      // Handle empty table scans
-      String emptyPlanTaskKey = planTaskKeyPrefix + 0;
-      IN_MEMORY_PLANNING_STATE.addPlanTask(emptyPlanTaskKey, Collections.emptyList());
-      return Pair.of(Collections.emptyList(), null);
-    }
-
     int planTaskSequence = 0;
     String previousPlanTask = null;
     String firstPlanTaskKey = null;
     List<FileScanTask> initialFileScanTasks = null;
+    boolean hasPlanTasks = false;
 
-    do {
-      List<FileScanTask> taskGrouping = taskIterator.next();
-      String planTaskKey = planTaskKeyPrefix + planTaskSequence++;
+    for (List<FileScanTask> taskGrouping : taskGroupings) {
+      hasPlanTasks = true;
+      String planTaskKey =
+          String.format("%s-%s-%s", planId, tableScan.table().uuid(), planTaskSequence++);
       IN_MEMORY_PLANNING_STATE.addPlanTask(planTaskKey, taskGrouping);
 
-      if (firstPlanTaskKey == null) {
-        firstPlanTaskKey = planTaskKey;
-        initialFileScanTasks = taskGrouping;
-      }
-
       if (previousPlanTask != null) {
         IN_MEMORY_PLANNING_STATE.addNextPlanTask(previousPlanTask, planTaskKey);
+      } else {
+        firstPlanTaskKey = planTaskKey;
+        initialFileScanTasks = taskGrouping;
       }
 
       previousPlanTask = planTaskKey;
-    } while (taskIterator.hasNext());
+    }
+
+    if (!hasPlanTasks) {
+      return Pair.of(Collections.emptyList(), null);
+    }
 
     return Pair.of(initialFileScanTasks, firstPlanTaskKey);
   }