Deprecate MergeSpecification#segString(Directory) (#14908)

Author: kitoha

lucene/CHANGES.txt

@@ -15,6 +15,8 @@ API Changes
 * GITHUB#14426: Support determining desired off-heap memory requirements through
   KnnVectorsReader::getOffHeapByteSize (Chris Hegarty)
 
+* GITHUB#14899: Deprecate MergeSpecification#segString(Directory) (kitoha)
+
 New Features
 ---------------------
 * GITHUB#14404: Introducing DocValuesMultiRangeQuery.SortedNumericStabbingBuilder into sandbox.

lucene/core/src/java/org/apache/lucene/index/MergePolicy.java

@@ -494,16 +494,15 @@ public void add(OneMerge merge) {
       merges.add(merge);
     }
 
-    // TODO: deprecate me (dir is never used!  and is sometimes difficult to provide!)
-    /** Returns a description of the merges in this specification. */
+    /**
+     * Returns a description of the merges in this specification
+     *
+     * @deprecated Use {@link #toString()} instead. The {@code Directory} parameter is ignored and
+     *     will be removed in a future release.
+     */
+    @Deprecated
     public String segString(Directory dir) {
-      StringBuilder b = new StringBuilder();
-      b.append("MergeSpec:\n");
-      final int count = merges.size();
-      for (int i = 0; i < count; i++) {
-        b.append("  ").append(1 + i).append(": ").append(merges.get(i).segString());
-      }
-      return b.toString();
+      return toString();
     }
 
     @Override