8258259: Unicode linebreak matching behavior is incorrect; backout JDK-8235812

Reviewed-by: naoto

Author: Stuart Marks

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

@@ -2063,7 +2063,7 @@ private Node expr(Node end) {
         Node prev = null;
         Node firstTail = null;
         Branch branch = null;
-        BranchConn branchConn = null;
+        Node branchConn = null;
 
         for (;;) {
             Node node = sequence(end);
@@ -2211,24 +2211,7 @@ private Node sequence(Node end) {
                 break;
             }
 
-            if (node instanceof LineEnding) {
-                LineEnding le = (LineEnding)node;
-                node = closureOfLineEnding(le);
-
-                if (node != le) {
-                    // LineEnding was replaced with an anonymous group
-                    if (head == null)
-                        head = node;
-                    else
-                        tail.next = node;
-                    // Double return: Tail was returned in root
-                    tail = root;
-                    continue;
-                }
-            } else {
-                node = closure(node);
-            }
-
+            node = closure(node);
             /* save the top dot-greedy nodes (.*, .+) as well
             if (node instanceof GreedyCharProperty &&
                 ((GreedyCharProperty)node).cp instanceof Dot) {
@@ -3096,31 +3079,18 @@ private Node group0() {
         if (saveTCNCount < topClosureNodes.size())
             topClosureNodes.subList(saveTCNCount, topClosureNodes.size()).clear();
 
-        return groupWithClosure(node, head, tail, capturingGroup);
-    }
-
-    /**
-     * Transforms a Group with quantifiers into some special constructs
-     * (such as Branch or Loop/GroupCurly), if necessary.
-     *
-     * This method is applied either to actual groups or to the Unicode
-     * linebreak (aka \\R) represented as an anonymous group.
-     */
-    private Node groupWithClosure(Node node, Node head, Node tail,
-                                  boolean capturingGroup)
-    {
         if (node instanceof Ques) {
             Ques ques = (Ques) node;
             if (ques.type == Qtype.POSSESSIVE) {
                 root = node;
                 return node;
             }
-            BranchConn branchConn = new BranchConn();
-            tail = tail.next = branchConn;
+            tail.next = new BranchConn();
+            tail = tail.next;
             if (ques.type == Qtype.GREEDY) {
-                head = new Branch(head, null, branchConn);
+                head = new Branch(head, null, tail);
             } else { // Reluctant quantifier
-                head = new Branch(null, head, branchConn);
+                head = new Branch(null, head, tail);
             }
             root = tail;
             return head;
@@ -3297,31 +3267,6 @@ private Node curly(Node prev, int cmin) {
         return new Curly(prev, cmin, MAX_REPS, qtype);
     }
 
-    /**
-     * Processing repetition of a Unicode linebreak \\R.
-     */
-    private Node closureOfLineEnding(LineEnding le) {
-        int ch = peek();
-        if (ch != '?' && ch != '*' && ch != '+' && ch != '{') {
-            return le;
-        }
-
-        // Replace the LineEnding with an anonymous group
-        // (?:\\u000D\\u000A|[\\u000A\\u000B\\u000C\\u000D\\u0085\\u2028\\u2029])
-        Node grHead = createGroup(true);
-        Node grTail = root;
-        BranchConn branchConn = new BranchConn();
-        branchConn.next = grTail;
-        Node slice = new Slice(new int[] {0x0D, 0x0A});
-        slice.next = branchConn;
-        Node chClass = newCharProperty(x -> x == 0x0A || x == 0x0B ||
-                x == 0x0C || x == 0x0D || x == 0x85 || x == 0x2028 ||
-                x == 0x2029);
-        chClass.next = branchConn;
-        grHead.next = new Branch(slice, chClass, branchConn);
-        return groupWithClosure(closure(grHead), grHead, grTail, false);
-    }
-
     /**
      * Processes repetition. If the next character peeked is a quantifier
      * then new nodes must be appended to handle the repetition.
@@ -4777,19 +4722,18 @@ boolean study(TreeInfo info) {
     static final class Branch extends Node {
         Node[] atoms = new Node[2];
         int size = 2;
-        BranchConn conn;
-        Branch(Node first, Node second, BranchConn branchConn) {
+        Node conn;
+        Branch(Node first, Node second, Node branchConn) {
             conn = branchConn;
             atoms[0] = first;
             atoms[1] = second;
         }
 
         void add(Node node) {
             if (size >= atoms.length) {
-                int len = ArraysSupport.newLength(size,
-                        1,    /* minimum growth */
-                        size  /* preferred growth */);
-                atoms = Arrays.copyOf(atoms, len);
+                Node[] tmp = new Node[atoms.length*2];
+                System.arraycopy(atoms, 0, tmp, 0, atoms.length);
+                atoms = tmp;
             }
             atoms[size++] = node;
         }

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
+ * 8216332 8214245 8237599 8241055 8247546 8258259
  *
  * @library /test/lib
  * @library /lib/testlibrary/java/lang
@@ -5063,7 +5063,15 @@ private static void surrogatePairWithCanonEq() {
         report("surrogatePairWithCanonEq");
     }
 
-    // This test is for 8235812
+    private static String s2x(String s) {
+        StringBuilder sb = new StringBuilder();
+        for (char ch : s.toCharArray()) {
+            sb.append(String.format("\\u%04x", (int)ch));
+        }
+        return sb.toString();
+    }
+
+    // This test is for 8235812, with cases excluded by 8258259
     private static void lineBreakWithQuantifier() {
         // key:    pattern
         // value:  lengths of input that must match the pattern
@@ -5073,22 +5081,22 @@ private static void lineBreakWithQuantifier() {
             Map.entry("\\R+",      List.of(1, 2, 3)),
             Map.entry("\\R{0}",    List.of(0)),
             Map.entry("\\R{1}",    List.of(1)),
-            Map.entry("\\R{2}",    List.of(2)),
-            Map.entry("\\R{3}",    List.of(3)),
+//          Map.entry("\\R{2}",    List.of(2)),            // 8258259
+//          Map.entry("\\R{3}",    List.of(3)),            // 8258259
             Map.entry("\\R{0,}",   List.of(0, 1, 2, 3)),
             Map.entry("\\R{1,}",   List.of(1, 2, 3)),
-            Map.entry("\\R{2,}",   List.of(2, 3)),
-            Map.entry("\\R{3,}",   List.of(3)),
+//          Map.entry("\\R{2,}",   List.of(2, 3)),         // 8258259
+//          Map.entry("\\R{3,}",   List.of(3)),            // 8258259
             Map.entry("\\R{0,0}",  List.of(0)),
             Map.entry("\\R{0,1}",  List.of(0, 1)),
             Map.entry("\\R{0,2}",  List.of(0, 1, 2)),
             Map.entry("\\R{0,3}",  List.of(0, 1, 2, 3)),
             Map.entry("\\R{1,1}",  List.of(1)),
             Map.entry("\\R{1,2}",  List.of(1, 2)),
             Map.entry("\\R{1,3}",  List.of(1, 2, 3)),
-            Map.entry("\\R{2,2}",  List.of(2)),
-            Map.entry("\\R{2,3}",  List.of(2, 3)),
-            Map.entry("\\R{3,3}",  List.of(3)),
+//          Map.entry("\\R{2,2}",  List.of(2)),            // 8258259
+//          Map.entry("\\R{2,3}",  List.of(2, 3)),         // 8258259
+//          Map.entry("\\R{3,3}",  List.of(3)),            // 8258259
             Map.entry("\\R",       List.of(1)),
             Map.entry("\\R\\R",    List.of(2)),
             Map.entry("\\R\\R\\R", List.of(3))
@@ -5131,7 +5139,7 @@ private static void lineBreakWithQuantifier() {
                         if (!m.reset(in).matches()) {
                             failCount++;
                             System.err.println("Expected to match '" +
-                                    in + "' =~ /" + p + "/");
+                                    s2x(in) + "' =~ /" + p + "/");
                         }
                     }
                 }