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8144733: Iterating over elements of a Scope can return spurious inner class elements

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When a Symbol is removed from a Scope while iterating over it, update the iterator as well to reflect the change.

Reviewed-by: mcimadamore
This commit is contained in:
Jan Lahoda 2016-08-08 17:22:44 +02:00
parent 335b44a953
commit d898c2f21c
2 changed files with 140 additions and 2 deletions
langtools
src/jdk.compiler/share/classes/com/sun/tools/javac/code
Scope.java
test/tools/javac/scope
IterateAndRemove.java

36
langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Scope.java

@ -296,6 +296,8 @@ public abstract class Scope {
*/
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 @@ public abstract class Scope {
te = te.sibling;
}
removeCount++;
//notify listeners
listeners.symbolRemoved(sym, this);
}
@ -569,15 +573,29 @@ public abstract class Scope {
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 @@ public abstract class Scope {
while (currEntry == null && currScope.next != null) {
currScope = currScope.next;
currEntry = currScope.elems;
seenRemoveCount = currScope.removeCount;
skipToNextMatchingEntry();
}
}
@ -618,13 +637,26 @@ public abstract class Scope {
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 @@ public abstract class Scope {
/** 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;

106
langtools/test/tools/javac/scope/IterateAndRemove.java Normal file

@ -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);
}
}
}
}
}
}