8269753: Misplaced caret in PatternSyntaxException's detail message

src/java.base/share/classes/java/util/regex/PatternSyntaxException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2021, 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
@@ -107,7 +107,9 @@ public String getMessage() {
         sb.append(pattern);
         if (index >= 0 && pattern != null && index < pattern.length()) {
             sb.append(System.lineSeparator());
-            for (int i = 0; i < index; i++) sb.append(' ');
+            for (int i = 0; i < index; i++) {
+                sb.append((pattern.charAt(i) == '\t') ? '\t' : ' ');
+            }
             sb.append('^');
         }
         return sb.toString();

test/jdk/java/util/regex/RegExTest.java

@@ -36,7 +36,7 @@
  * 8151481 4867170 7080302 6728861 6995635 6736245 4916384 6328855 6192895
  * 6345469 6988218 6693451 7006761 8140212 8143282 8158482 8176029 8184706
  * 8194667 8197462 8184692 8221431 8224789 8228352 8230829 8236034 8235812
- * 8216332 8214245 8237599 8241055 8247546 8258259 8037397
+ * 8216332 8214245 8237599 8241055 8247546 8258259 8037397 8269753
  *
  * @library /test/lib
  * @library /lib/testlibrary/java/lang
@@ -198,6 +198,7 @@ public static void main(String[] args) throws Exception {
         caseInsensitivePMatch();
         surrogatePairOverlapRegion();
         droppedClassesWithIntersection();
+        errorMessageCaretIndentation();
 
 
         if (failure) {
@@ -5289,5 +5290,23 @@ private static void droppedClassesWithIntersection() {
             System.out.println("Compiling intersection pattern is matching digits where it should not");
         }
 
+        report("Dropped classes with intersection.");
+
+    }
+
+    //This test is for 8269753
+    private static void errorMessageCaretIndentation() {
+        String pattern = "\t**";
+
+        try {
+            var res = Pattern.compile(pattern);
+        } catch (PatternSyntaxException e) {
+            var message = e.getMessage();
+            var sep = System.lineSeparator();
+            if (!message.contains(sep + "\t ^")){
+                failCount++;
+            }
+        }
+        report("Correct caret indentation for patterns with tabs");
     }
 }