# HG changeset patch
# User igerasim
# Date 1553630489 25200
#      Tue Mar 26 13:01:29 2019 -0700
# Node ID 50d1fd7c97b996f1a4a0f5016e64787b3e43f987
# Parent  8af48416e31f7c49f315e7b4b8c66c94cc3c9685
8221430: StringBuffer(CharSequence) constructor truncates when -XX:-CompactStrings specified
Reviewed-by: igerasim, rriggs
Contributed-by: Andrew Leonard <andrew_m_leonard@uk.ibm.com>

diff --git a/src/java.base/share/classes/java/lang/AbstractStringBuilder.java b/src/java.base/share/classes/java/lang/AbstractStringBuilder.java
--- a/src/java.base/share/classes/java/lang/AbstractStringBuilder.java
+++ b/src/java.base/share/classes/java/lang/AbstractStringBuilder.java
@@ -92,19 +92,24 @@
     }
 
     /**
-     * Creates an AbstractStringBuilder with the specified coder and with
+     * Creates an AbstractStringBuilder with the specified coder
+     * (coderHint is used when compact strings are enabled) and with
      * the initial capacity equal to the smaller of (length + addition)
      * and Integer.MAX_VALUE.
      */
-    AbstractStringBuilder(byte coder, int length, int addition) {
+    AbstractStringBuilder(byte coderHint, int length, int addition) {
         if (length < 0) {
             throw new NegativeArraySizeException("Negative length: " + length);
         }
-        this.coder = coder;
         int capacity = (length < Integer.MAX_VALUE - addition)
                 ? length + addition : Integer.MAX_VALUE;
-        value = (coder == LATIN1)
-                ? new byte[capacity] : StringUTF16.newBytesFor(capacity);
+        if (COMPACT_STRINGS && coderHint == LATIN1) {
+            value = new byte[capacity];
+            coder = LATIN1;
+        } else {
+            value = StringUTF16.newBytesFor(capacity);
+            coder = UTF16;
+        }
     }
 
     /**
@@ -1741,4 +1746,18 @@
                 "start " + start + ", end " + end + ", length " + len);
         }
     }
+
+    /**
+     * Determines the "coder" of the given CharSequence.
+     * If the coder cannot be determined, returns LATIN1.
+     */
+    static byte getCharSequenceCoderHint(CharSequence seq) {
+        if (seq instanceof String) {
+            return ((String)seq).coder();
+        } else if (seq instanceof AbstractStringBuilder) {
+            return ((AbstractStringBuilder)seq).getCoder();
+        } else {
+            return LATIN1;
+        }
+    }
 }
diff --git a/src/java.base/share/classes/java/lang/StringBuffer.java b/src/java.base/share/classes/java/lang/StringBuffer.java
--- a/src/java.base/share/classes/java/lang/StringBuffer.java
+++ b/src/java.base/share/classes/java/lang/StringBuffer.java
@@ -162,7 +162,7 @@
      * @since 1.5
      */
     public StringBuffer(CharSequence seq) {
-        super(String.LATIN1, seq.length(), 16);
+        super(getCharSequenceCoderHint(seq), seq.length(), 16);
         append(seq);
     }
 
diff --git a/src/java.base/share/classes/java/lang/StringBuilder.java b/src/java.base/share/classes/java/lang/StringBuilder.java
--- a/src/java.base/share/classes/java/lang/StringBuilder.java
+++ b/src/java.base/share/classes/java/lang/StringBuilder.java
@@ -134,7 +134,7 @@
      * @param      seq   the sequence to copy.
      */
     public StringBuilder(CharSequence seq) {
-        super(String.LATIN1, seq.length(), 16);
+        super(getCharSequenceCoderHint(seq), seq.length(), 16);
         append(seq);
     }
 
diff --git a/test/jdk/java/lang/StringBuffer/CompactStringBuffer.java b/test/jdk/java/lang/StringBuffer/CompactStringBuffer.java
--- a/test/jdk/java/lang/StringBuffer/CompactStringBuffer.java
+++ b/test/jdk/java/lang/StringBuffer/CompactStringBuffer.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -30,7 +30,7 @@
 
 /*
  * @test
- * @bug 8077559
+ * @bug 8077559 8221430
  * @summary Tests Compact String. This test is testing StringBuffer
  *          behavior related to Compact String.
  * @run testng/othervm -XX:+CompactStrings CompactStringBuffer
@@ -440,6 +440,12 @@
               "abcdefgh1.23456");
         check(new StringBuffer().append(bmp).append(1.23456).toString(),
               "\u4e00\u4e01\u4e02\u4e03\u4e04\u4e05\u4e06\u4e07\u4e081.23456");
+
+        ////////////////////////////////////////////////////////////////////
+        check(new StringBuffer((CharSequence)new StringBuffer(ascii)).toString(),
+              ascii);
+        check(new StringBuffer((CharSequence)new StringBuffer(asciiMixed)).toString(),
+              asciiMixed);
     }
 
     private void checkGetChars(StringBuffer sb, int srcBegin, int srcEnd,