From 913862f97766675f5a02cc00c90afb7d873ef2a4 Mon Sep 17 00:00:00 2001
From: mattirn <matti.rintanikkola@gmail.com>
Date: Sun, 24 Jan 2021 12:48:50 +0100
Subject: [PATCH] After JLine has trimmed history history-search-backward
 widget does not work well, fixes #643

---
 .../reader/impl/history/DefaultHistory.java      | 16 +++++++++++-----
 .../jline/reader/impl/history/HistoryTest.java   |  4 ++--
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/reader/src/main/java/org/jline/reader/impl/history/DefaultHistory.java b/reader/src/main/java/org/jline/reader/impl/history/DefaultHistory.java
index d2c030b9d..036bca55b 100644
--- a/reader/src/main/java/org/jline/reader/impl/history/DefaultHistory.java
+++ b/reader/src/main/java/org/jline/reader/impl/history/DefaultHistory.java
@@ -257,11 +257,11 @@ protected void trimHistory(Path path, int max) throws IOException {
             });
         }
         // Remove duplicates
-        doTrimHistory(allItems, max);
+        List<Entry> trimmedItems = doTrimHistory(allItems, max);
         // Write history
         Path temp = Files.createTempFile(path.toAbsolutePath().getParent(), path.getFileName().toString(), ".tmp");
         try (BufferedWriter writer = Files.newBufferedWriter(temp, StandardOpenOption.WRITE)) {
-            for (Entry entry : allItems) {
+            for (Entry entry : trimmedItems) {
                 writer.append(format(entry));
             }
         }
@@ -269,8 +269,8 @@ protected void trimHistory(Path path, int max) throws IOException {
         // Keep items in memory
         if (isLineReaderHistory(path)) {
             internalClear();
-            offset = allItems.get(0).index();
-            items.addAll(allItems);
+            offset = trimmedItems.get(0).index();
+            items.addAll(trimmedItems);
             setHistoryFileData(path, new HistoryFileData(items.size(), items.size()));
         } else {
             setEntriesInFile(path, allItems.size());
@@ -296,7 +296,7 @@ private void internalClear() {
         items.clear();
     }
 
-    static void doTrimHistory(List<Entry> allItems, int max) {
+    static List<Entry> doTrimHistory(List<Entry> allItems, int max) {
         int idx = 0;
         while (idx < allItems.size()) {
             int ridx = allItems.size() - idx - 1;
@@ -313,6 +313,12 @@ static void doTrimHistory(List<Entry> allItems, int max) {
         while (allItems.size() > max) {
             allItems.remove(0);
         }
+        int index = allItems.get(allItems.size() - 1).index() - allItems.size() + 1;
+        List<Entry> out = new ArrayList<>();
+        for (Entry e : allItems) {
+            out.add(new EntryImpl(index++, e.time(), e.line()));
+        }
+        return out;
     }
 
     public int size() {
diff --git a/reader/src/test/java/org/jline/reader/impl/history/HistoryTest.java b/reader/src/test/java/org/jline/reader/impl/history/HistoryTest.java
index 29f74ea6f..c061464b0 100644
--- a/reader/src/test/java/org/jline/reader/impl/history/HistoryTest.java
+++ b/reader/src/test/java/org/jline/reader/impl/history/HistoryTest.java
@@ -141,10 +141,10 @@ public void testTrim() {
         entries.add(new DefaultHistory.EntryImpl(8, Instant.now(), "a"));
 
         List<History.Entry> trimmed = new ArrayList<>(entries);
-        DefaultHistory.doTrimHistory(trimmed, 6);
+        trimmed = DefaultHistory.doTrimHistory(trimmed, 6);
         assertEquals(5, trimmed.size());
 
-        DefaultHistory.doTrimHistory(trimmed, 3);
+        trimmed = DefaultHistory.doTrimHistory(trimmed, 3);
         assertEquals(3, trimmed.size());
         assertEquals("c", trimmed.get(0).line());
         assertEquals("b", trimmed.get(1).line());