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Fixing bug : False -: DoubleCheckedLocking with reversed null check - ID: 2835074

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git-svn-id: https://pmd.svn.sourceforge.net/svnroot/pmd/branches/pmd/4.2.x@6976 51baf565-9d33-0410-a72c-fc3788e3496d
This commit is contained in:
Romain Pelisse
2009-08-15 15:58:49 +00:00
parent d6b326838f
commit 6f427f9fa5
3 changed files with 72 additions and 8 deletions
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1
pmd/etc/changelog.txt
View File

@ -5,6 +5,7 @@ Fixed bug 2317099 - False + in SimplifyCondition
Fixed bug 2606609 - False "UnusedImports" positive in package-info.java
Fixed bug 2645268 - ClassCastException in UselessOperationOnImmutable.getDeclaration
Fixed bug 2724653 - AvoidThreadGroup reports false positives
Fixed bug 2835074 - False -: DoubleCheckedLocking with reversed null check
Correct -benchmark reporting of Rule visits via the RuleChain
Fix issue with Type Resolution incorrectly handling of Classes with same name as a java.lang Class.

44
pmd/regress/test/net/sourceforge/pmd/rules/basic/xml/DoubleCheckedLocking.xml
View File

@ -55,4 +55,48 @@ public class Foo {
]]></code>
<source-type>java 1.5</source-type>
</test-code>
<test-code>
<description><![CDATA[
inversed null check -see bug 2835074 False -: DoubleCheckedLocking with reversed null check
2835074 False -: DoubleCheckedLocking with reversed null check
]]></description>
<expected-problems>1</expected-problems>
<code><![CDATA[
public class Foo {
Object baz;
Object bar() {
if(null == baz) { //baz may be non-null yet not fully created
synchronized(this){
if(baz == null){
baz = new Object();
}
}
}
return baz;
}
}
]]></code>
</test-code>
<test-code>
<description><![CDATA[
inversed null check -see bug 2835074 False -: DoubleCheckedLocking with reversed null check
2835074 False -: DoubleCheckedLocking with reversed null check
]]></description>
<expected-problems>1</expected-problems>
<code><![CDATA[
public class Foo {
Object baz;
Object bar() {
if(baz == null) { //baz may be non-null yet not fully created
synchronized(this){
if(null == baz){
baz = new Object();
}
}
}
return baz;
}
}
]]></code>
</test-code>
</test-data>

31
pmd/src/net/sourceforge/pmd/rules/DoubleCheckedLocking.java
View File

@ -3,6 +3,7 @@
*/
package net.sourceforge.pmd.rules;
import net.sourceforge.pmd.AbstractJavaRule;
import net.sourceforge.pmd.ast.ASTAssignmentOperator;
import net.sourceforge.pmd.ast.ASTClassOrInterfaceDeclaration;
import net.sourceforge.pmd.ast.ASTIfStatement;
@ -41,7 +42,7 @@ import java.util.List;
*
* @author CL Gilbert (dnoyeb@users.sourceforge.net)
*/
public class DoubleCheckedLocking extends net.sourceforge.pmd.AbstractRule {
public class DoubleCheckedLocking extends AbstractJavaRule {
public Object visit(ASTClassOrInterfaceDeclaration node, Object data) {
if (node.isInterface()) {
@ -120,11 +121,10 @@ public class DoubleCheckedLocking extends net.sourceforge.pmd.AbstractRule {
List<ASTPrimaryExpression> finder = new ArrayList<ASTPrimaryExpression>();
is.findChildrenOfType(ASTPrimaryExpression.class, finder, true);
if (finder.size() > 1) {
ASTPrimaryExpression apeLeft = finder.get(0);
if (matchName(apeLeft, varname)) {
ASTPrimaryExpression apeRight = finder.get(1);
if ((apeRight.jjtGetNumChildren() == 1) && (apeRight.jjtGetChild(0) instanceof ASTPrimaryPrefix)) {
ASTPrimaryPrefix pp2 = (ASTPrimaryPrefix) apeRight.jjtGetChild(0);
ASTPrimaryExpression nullStmt = findNonVariableStmt(varname,finder.get(0),finder.get(1));
if ( nullStmt != null ) {
if ((nullStmt.jjtGetNumChildren() == 1) && (nullStmt.jjtGetChild(0) instanceof ASTPrimaryPrefix)) {
ASTPrimaryPrefix pp2 = (ASTPrimaryPrefix) nullStmt.jjtGetChild(0);
if ((pp2.jjtGetNumChildren() == 1) && (pp2.jjtGetChild(0) instanceof ASTLiteral)) {
ASTLiteral lit = (ASTLiteral) pp2.jjtGetChild(0);
if ((lit.jjtGetNumChildren() == 1) && (lit.jjtGetChild(0) instanceof ASTNullLiteral)) {
@ -137,6 +137,25 @@ public class DoubleCheckedLocking extends net.sourceforge.pmd.AbstractRule {
return false;
}
/**
* <p>Sort out if apeLeft or apeRight are variable with the provided 'variableName'.</p>
*
* @param variableName
* @param apeLeft
* @param apeRight
* @return reference from either apeLeft or apeRight, if one of them match, or 'null', if none match.
*/
private ASTPrimaryExpression findNonVariableStmt(String variableName,
ASTPrimaryExpression apeLeft, ASTPrimaryExpression apeRight) {
if (matchName(apeLeft, variableName) ) {
return apeRight;
}
else if (matchName(apeRight, variableName) ) {
return apeLeft;
}
return null;
}
private boolean matchName(ASTPrimaryExpression ape, String name) {
if ((ape.jjtGetNumChildren() == 1) && (ape.jjtGetChild(0) instanceof ASTPrimaryPrefix)) {
ASTPrimaryPrefix pp = (ASTPrimaryPrefix) ape.jjtGetChild(0);