Use default sort order when custom sort order is identical (fixes #956) (#957)

Author: valepakh

reader/src/main/java/org/jline/reader/impl/LineReaderImpl.java

@@ -5204,45 +5204,47 @@ protected PostResult computePost(
             boolean groupName,
             boolean rowsFirst) {
         List<Object> strings = new ArrayList<>();
-        boolean customOrder = possible.stream().anyMatch(c -> c.sort() != 0);
         if (groupName) {
             Comparator<String> groupComparator = getGroupComparator();
-            Map<String, Map<Object, Candidate>> sorted;
+            Map<String, List<Candidate>> sorted;
             sorted = groupComparator != null ? new TreeMap<>(groupComparator) : new LinkedHashMap<>();
             for (Candidate cand : possible) {
                 String group = cand.group();
-                sorted.computeIfAbsent(group != null ? group : "", s -> new LinkedHashMap<>())
-                        .put((customOrder ? cand.sort() : cand.value()), cand);
+                sorted.computeIfAbsent(group != null ? group : "", s -> new ArrayList<>())
+                        .add(cand);
             }
-            for (Map.Entry<String, Map<Object, Candidate>> entry : sorted.entrySet()) {
+            for (Map.Entry<String, List<Candidate>> entry : sorted.entrySet()) {
                 String group = entry.getKey();
                 if (group.isEmpty() && sorted.size() > 1) {
                     group = getOthersGroupName();
                 }
                 if (!group.isEmpty() && autoGroup) {
                     strings.add(group);
                 }
-                strings.add(new ArrayList<>(entry.getValue().values()));
+                List<Candidate> candidates = entry.getValue();
+                Collections.sort(candidates);
+                strings.add(candidates);
                 if (ordered != null) {
-                    ordered.addAll(entry.getValue().values());
+                    ordered.addAll(candidates);
                 }
             }
         } else {
             Set<String> groups = new LinkedHashSet<>();
-            TreeMap<Object, Candidate> sorted = new TreeMap<>();
+            List<Candidate> sorted = new ArrayList<>();
             for (Candidate cand : possible) {
                 String group = cand.group();
                 if (group != null) {
                     groups.add(group);
                 }
-                sorted.put((customOrder ? cand.sort() : cand.value()), cand);
+                sorted.add(cand);
             }
             if (autoGroup) {
                 strings.addAll(groups);
             }
-            strings.add(new ArrayList<>(sorted.values()));
+            Collections.sort(sorted);
+            strings.add(sorted);
             if (ordered != null) {
-                ordered.addAll(sorted.values());
+                ordered.addAll(sorted);
             }
         }
         return toColumns(strings, selection, completed, wcwidth, width, rowsFirst);

reader/src/test/java/org/jline/reader/impl/CandidateCustomSortTest.java

@@ -13,6 +13,7 @@
 import java.util.List;
 
 import org.jline.reader.Candidate;
+import org.jline.reader.LineReader.Option;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -80,4 +81,28 @@ public void testCompletionSort() throws Exception {
         });
         assertBuffer("foo", new TestBuffer("").tab().tab());
     }
+
+    @Test
+    public void testCustomSortIdenticalSortValueGroups() {
+        List<Candidate> candidates = Arrays.asList(
+                new Candidate("foo", "foo", null, null, null, null, true, 1),
+                new Candidate("bar", "bar", null, null, null, null, true, 1),
+                new Candidate("zoo", "zoo", null, null, null, null, true, 1),
+                new Candidate("zzz", "zzz", null, null, null, null, true, 0));
+        reader.setOpt(Option.GROUP);
+        String postResult = reader.computePost(candidates, null, null, "").post.toString();
+        assertEquals("zzz   bar   foo   zoo", postResult);
+    }
+
+    @Test
+    public void testCustomSortIdenticalSortValue() {
+        List<Candidate> candidates = Arrays.asList(
+                new Candidate("foo", "foo", null, null, null, null, true, 1),
+                new Candidate("bar", "bar", null, null, null, null, true, 1),
+                new Candidate("zoo", "zoo", null, null, null, null, true, 1),
+                new Candidate("zzz", "zzz", null, null, null, null, true, 0));
+        reader.unsetOpt(Option.GROUP);
+        String postResult = reader.computePost(candidates, null, null, "").post.toString();
+        assertEquals("zzz   bar   foo   zoo", postResult);
+    }
 }