8144733: Iterating over elements of a Scope can return spurious inner class elements
Summary: When a Symbol is removed from a Scope while iterating over it, update the iterator as well to reflect the change.
Reviewed-by: mcimadamore
--- a/langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Scope.java Thu Aug 04 17:48:48 2016 +0000
+++ b/langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Scope.java Mon Aug 08 17:22:44 2016 +0200
@@ -296,6 +296,8 @@
*/
int nelems = 0;
+ int removeCount = 0;
+
/** Use as a "not-found" result for lookup.
* Also used to mark deleted entries in the table.
*/
@@ -474,6 +476,8 @@
te = te.sibling;
}
+ removeCount++;
+
//notify listeners
listeners.symbolRemoved(sym, this);
}
@@ -569,15 +573,29 @@
return new Iterator<Symbol>() {
private ScopeImpl currScope = ScopeImpl.this;
private Scope.Entry currEntry = elems;
+ private int seenRemoveCount = currScope.removeCount;
{
update();
}
public boolean hasNext() {
+ if (seenRemoveCount != currScope.removeCount &&
+ currEntry != null &&
+ !currEntry.scope.includes(currEntry.sym)) {
+ doNext(); //skip entry that is no longer in the Scope
+ seenRemoveCount = currScope.removeCount;
+ }
return currEntry != null;
}
public Symbol next() {
+ if (!hasNext()) {
+ throw new NoSuchElementException();
+ }
+
+ return doNext();
+ }
+ private Symbol doNext() {
Symbol sym = (currEntry == null ? null : currEntry.sym);
if (currEntry != null) {
currEntry = currEntry.sibling;
@@ -596,6 +614,7 @@
while (currEntry == null && currScope.next != null) {
currScope = currScope.next;
currEntry = currScope.elems;
+ seenRemoveCount = currScope.removeCount;
skipToNextMatchingEntry();
}
}
@@ -618,13 +637,26 @@
public Iterator<Symbol> iterator() {
return new Iterator<Symbol>() {
Scope.Entry currentEntry = lookup(name, sf);
+ int seenRemoveCount = currentEntry.scope != null ?
+ currentEntry.scope.removeCount : -1;
public boolean hasNext() {
+ if (currentEntry.scope != null &&
+ seenRemoveCount != currentEntry.scope.removeCount &&
+ !currentEntry.scope.includes(currentEntry.sym)) {
+ doNext(); //skip entry that is no longer in the Scope
+ }
return currentEntry.scope != null &&
(lookupKind == RECURSIVE ||
currentEntry.scope == ScopeImpl.this);
}
public Symbol next() {
+ if (!hasNext()) {
+ throw new NoSuchElementException();
+ }
+ return doNext();
+ }
+ private Symbol doNext() {
Scope.Entry prevEntry = currentEntry;
currentEntry = currentEntry.next(sf);
return prevEntry.sym;
@@ -686,9 +718,9 @@
/** The entry's scope.
* scope == null iff this == sentinel
*/
- public Scope scope;
+ public ScopeImpl scope;
- public Entry(Symbol sym, Entry shadowed, Entry sibling, Scope scope) {
+ public Entry(Symbol sym, Entry shadowed, Entry sibling, ScopeImpl scope) {
this.sym = sym;
this.shadowed = shadowed;
this.sibling = sibling;
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/scope/IterateAndRemove.java Mon Aug 08 17:22:44 2016 +0200
@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2016, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8144733
+ * @summary Verify that Scope.remove removes the Symbol also from already running iterations.
+ * @modules jdk.compiler/com.sun.tools.javac.code
+ * jdk.compiler/com.sun.tools.javac.util
+ */
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.function.Function;
+
+import com.sun.tools.javac.code.Scope;
+import com.sun.tools.javac.code.Scope.WriteableScope;
+import com.sun.tools.javac.code.Symbol;
+import com.sun.tools.javac.code.Symbol.PackageSymbol;
+import com.sun.tools.javac.util.Context;
+import com.sun.tools.javac.util.Name;
+import com.sun.tools.javac.util.Names;
+
+public class IterateAndRemove {
+ public static void main(String... args) {
+ new IterateAndRemove().run();
+ }
+
+ void run() {
+ Context ctx = new Context();
+ Names names = Names.instance(ctx);
+ Symbol root = new PackageSymbol(names.empty, null);
+ Name one = names.fromString("1");
+ PackageSymbol sym1 = new PackageSymbol(one, new PackageSymbol(names.fromString("a"), root));
+ PackageSymbol sym2 = new PackageSymbol(one, new PackageSymbol(names.fromString("b"), root));
+ PackageSymbol sym3 = new PackageSymbol(one, new PackageSymbol(names.fromString("c"), root));
+ List<Symbol> symbols = Arrays.asList(sym1, sym2, sym3);
+
+ List<Function<Scope, Iterable<Symbol>>> getters = Arrays.asList(
+ scope -> scope.getSymbols(),
+ scope -> scope.getSymbolsByName(one)
+ );
+ for (Function<Scope, Iterable<Symbol>> scope2Content : getters) {
+ for (int removeAt : new int[] {0, 1, 2, 3}) {
+ for (Symbol removeWhat : new Symbol[] {sym1, sym2, sym3}) {
+ WriteableScope s = WriteableScope.create(root);
+
+ symbols.forEach(s :: enter);
+
+ Iterator<Symbol> it = scope2Content.apply(s).iterator();
+ List<PackageSymbol> actual = new ArrayList<>();
+ int count = 0;
+
+ while (true) {
+ if (count++ == removeAt)
+ s.remove(removeWhat);
+ if (!it.hasNext())
+ break;
+ actual.add((PackageSymbol) it.next());
+ }
+
+ List<Symbol> copy = new ArrayList<>(symbols);
+
+ Collections.reverse(copy);
+
+ count = 0;
+
+ while (true) {
+ if (count == removeAt && copy.indexOf(removeWhat) >= count)
+ copy.remove(removeWhat);
+ count++;
+ if (count >= copy.size())
+ break;
+ }
+
+ if (!copy.equals(actual)) {
+ throw new AssertionError("differs: actual: " + actual + "; expected: " + copy);
+ }
+ }
+ }
+ }
+ }
+}
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