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6563143: javac should issue a warning for overriding equals without hashCode

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Reviewed-by: jjg, mcimadamore
This commit is contained in:
Vicente Romero 2013-02-18 14:33:25 +00:00
parent b2a3c762ff
commit e6b61ae08a
10 changed files with 71 additions and 8 deletions
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7
langtools/src/share/classes/com/sun/tools/javac/code/Flags.java
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@ -258,7 +258,7 @@ public class Flags {
public static final long CLASH = 1L<<42;
/**
* Flag that marks either a default method or an interface containing default methods
* Flag that marks either a default method or an interface containing default methods.
*/
public static final long DEFAULT = 1L<<43;
@ -268,6 +268,11 @@ public class Flags {
*/
public static final long AUXILIARY = 1L<<44;
/**
* Flag that indicates that an override error has been detected by Check.
*/
public static final long BAD_OVERRIDE = 1L<<45;
/** Modifier masks.
*/
public static final int

3
langtools/src/share/classes/com/sun/tools/javac/code/Lint.java
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@ -26,10 +26,7 @@
package com.sun.tools.javac.code;
import java.util.EnumSet;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import javax.lang.model.element.Modifier;
import com.sun.tools.javac.code.Symbol.*;
import com.sun.tools.javac.util.Context;
import com.sun.tools.javac.util.List;

1
langtools/src/share/classes/com/sun/tools/javac/comp/Attr.java
View File

@ -3991,6 +3991,7 @@ public class Attr extends JCTree.Visitor {
attribClassBody(env, c);
chk.checkDeprecatedAnnotation(env.tree.pos(), c);
chk.checkClassOverrideEqualsAndHash(c);
} finally {
env.info.returnResult = prevReturnRes;
log.useSource(prev);

32
langtools/src/share/classes/com/sun/tools/javac/comp/Check.java
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@ -1588,6 +1588,7 @@ public class Check {
(other.flags() & STATIC) == 0) {
log.error(TreeInfo.diagnosticPositionFor(m, tree), "override.static",
cannotOverride(m, other));
m.flags_field |= BAD_OVERRIDE;
return;
}
@ -1599,6 +1600,7 @@ public class Check {
log.error(TreeInfo.diagnosticPositionFor(m, tree), "override.meth",
cannotOverride(m, other),
asFlagSet(other.flags() & (FINAL | STATIC)));
m.flags_field |= BAD_OVERRIDE;
return;
}
@ -1615,6 +1617,7 @@ public class Check {
other.flags() == 0 ?
Flag.PACKAGE :
asFlagSet(other.flags() & AccessFlags));
m.flags_field |= BAD_OVERRIDE;
return;
}
@ -1642,6 +1645,7 @@ public class Check {
"override.incompatible.ret",
cannotOverride(m, other),
mtres, otres);
m.flags_field |= BAD_OVERRIDE;
return;
}
} else if (overrideWarner.hasNonSilentLint(LintCategory.UNCHECKED)) {
@ -1661,6 +1665,7 @@ public class Check {
"override.meth.doesnt.throw",
cannotOverride(m, other),
unhandledUnerased.head);
m.flags_field |= BAD_OVERRIDE;
return;
}
else if (unhandledUnerased.nonEmpty()) {
@ -1956,6 +1961,33 @@ public class Check {
}
}
public void checkClassOverrideEqualsAndHash(ClassSymbol someClass) {
if (lint.isEnabled(LintCategory.OVERRIDES)) {
boolean hasEquals = false;
boolean hasHashCode = false;
Scope.Entry equalsAtObject = syms.objectType.tsym.members().lookup(names.equals);
Scope.Entry hashCodeAtObject = syms.objectType.tsym.members().lookup(names.hashCode);
for (Symbol s: someClass.members().getElements(new Filter<Symbol>() {
public boolean accepts(Symbol s) {
return s.kind == Kinds.MTH &&
(s.flags() & BAD_OVERRIDE) == 0;
}
})) {
MethodSymbol m = (MethodSymbol)s;
hasEquals |= m.name.equals(names.equals) &&
m.overrides(equalsAtObject.sym, someClass, types, false);
hasHashCode |= m.name.equals(names.hashCode) &&
m.overrides(hashCodeAtObject.sym, someClass, types, false);
}
if (hasEquals && !hasHashCode) {
log.warning(LintCategory.OVERRIDES, (DiagnosticPosition) null,
"override.equals.but.not.hashcode", someClass.fullname);
}
}
}
private boolean checkNameClash(ClassSymbol origin, Symbol s1, Symbol s2) {
ClashFilter cf = new ClashFilter(origin.type);
return (cf.accepts(s1) &&

1
langtools/src/share/classes/com/sun/tools/javac/comp/Resolve.java
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@ -3606,6 +3606,7 @@ public class Resolve {
* while inapplicable candidates contain further details about the
* reason why the method has been considered inapplicable.
*/
@SuppressWarnings("overrides")
class Candidate {
final MethodResolutionPhase step;

5
langtools/src/share/classes/com/sun/tools/javac/resources/compiler.properties
View File

@ -2065,6 +2065,11 @@ compiler.warn.override.unchecked.thrown=\
{0}\n\
overridden method does not throw {1}
# 0: class name
compiler.warn.override.equals.but.not.hashcode=\
Class {0}\n\
overrides method equals but does not overrides method hashCode from Object
## The following are all possible strings for the first argument ({0}) of the
## above strings.
# 0: symbol, 1: symbol, 2: symbol, 3: symbol

5
langtools/src/share/classes/com/sun/tools/sjavac/comp/Dependencies.java
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@ -1,5 +1,5 @@
/*
* Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1999, 2013, 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
@ -113,9 +113,6 @@ public class Dependencies {
return a.toString().compareTo(b.toString());
}
public boolean equals(Object obj) {
return super.equals(obj);
}
}
/**

22
langtools/test/tools/javac/6563143/OverridesEqualsButNotHashCodeTest.java Normal file
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@ -0,0 +1,22 @@
/*
* @test /nodynamiccopyright/
* @bug 6563143
* @summary javac should issue a warning for overriding equals without hashCode
* @compile/ref=OverridesEqualsButNotHashCodeTest.out -Xlint:overrides -XDrawDiagnostics OverridesEqualsButNotHashCodeTest.java
*/
@SuppressWarnings("overrides")
public class OverridesEqualsButNotHashCodeTest {
@Override
public boolean equals(Object o) {
return o == this;
}
}
class Other {
@Override
public boolean equals(Object o) {
return o == this;
}
}

2
langtools/test/tools/javac/6563143/OverridesEqualsButNotHashCodeTest.out Normal file
View File

@ -0,0 +1,2 @@
- compiler.warn.override.equals.but.not.hashcode: Other
1 warning

1
langtools/test/tools/javac/diags/examples.not-yet.txt
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@ -110,4 +110,5 @@ compiler.warn.unchecked.cast.to.type # DEAD, replaced by comp
compiler.warn.unexpected.archive.file # Paths: zip file with unknown extn
compiler.warn.unknown.enum.constant # in bad class file
compiler.warn.unknown.enum.constant.reason # in bad class file
compiler.warn.override.equals.but.not.hashcode # when a class overrides equals but not hashCode method from Object