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7196163: Project Coin: Allow effectively final variables to be used as resources in try-with-resources

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Allowing final variables as operands to try-with-resources; also reviewed by Sergei Pikalev.

Reviewed-by: darcy, mcimadamore, vromero
This commit is contained in:
Jan Lahoda 2014-11-19 13:46:04 +01:00
parent 9d6d069c22
commit a2b0a2413e
20 changed files with 398 additions and 19 deletions
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1
langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Kinds.java
View file

@ -168,6 +168,7 @@ public class Kinds {
public static final KindSelector MTH = new KindSelector(0x10);
public static final KindSelector ERR = new KindSelector(0x3f);
public static final KindSelector POLY = new KindSelector(0x20);
public static final KindSelector ASG = new KindSelector(0x44);
//common derived selectors
public static final KindSelector TYP_PCK = of(TYP, PCK);

3
langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Source.java
View file

@ -140,6 +140,9 @@ public enum Source {
public boolean allowTryWithResources() {
return compareTo(JDK1_7) >= 0;
}
public boolean allowEffectivelyFinalVariablesInTryWithResources() {
return compareTo(JDK1_9) >= 0;
}
public boolean allowBinaryLiterals() {
return compareTo(JDK1_7) >= 0;
}

18
langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Attr.java
View file

@ -148,7 +148,7 @@ public class Attr extends JCTree.Visitor {
identifyLambdaCandidate = options.getBoolean("identifyLambdaCandidate", false);
statInfo = new ResultInfo(KindSelector.NIL, Type.noType);
varInfo = new ResultInfo(KindSelector.VAR, Type.noType);
varAssignmentInfo = new ResultInfo(KindSelector.ASG, Type.noType);
unknownExprInfo = new ResultInfo(KindSelector.VAL, Type.noType);
unknownAnyPolyInfo = new ResultInfo(KindSelector.VAL, Infer.anyPoly);
unknownTypeInfo = new ResultInfo(KindSelector.TYP, Type.noType);
@ -498,7 +498,7 @@ public class Attr extends JCTree.Visitor {
}
final ResultInfo statInfo;
final ResultInfo varInfo;
final ResultInfo varAssignmentInfo;
final ResultInfo unknownAnyPolyInfo;
final ResultInfo unknownExprInfo;
final ResultInfo unknownTypeInfo;
@ -1293,7 +1293,7 @@ public class Attr extends JCTree.Visitor {
}
};
ResultInfo twrResult =
new ResultInfo(KindSelector.VAL,
new ResultInfo(KindSelector.VAR,
syms.autoCloseableType,
twrContext);
if (resource.hasTag(VARDEF)) {
@ -2942,7 +2942,7 @@ public class Attr extends JCTree.Visitor {
}
public void visitAssign(JCAssign tree) {
Type owntype = attribTree(tree.lhs, env.dup(tree), varInfo);
Type owntype = attribTree(tree.lhs, env.dup(tree), varAssignmentInfo);
Type capturedType = capture(owntype);
attribExpr(tree.rhs, env, owntype);
result = check(tree, capturedType, KindSelector.VAL, resultInfo);
@ -2950,7 +2950,7 @@ public class Attr extends JCTree.Visitor {
public void visitAssignop(JCAssignOp tree) {
// Attribute arguments.
Type owntype = attribTree(tree.lhs, env, varInfo);
Type owntype = attribTree(tree.lhs, env, varAssignmentInfo);
Type operand = attribExpr(tree.rhs, env);
// Find operator.
Symbol operator = tree.operator = rs.resolveBinaryOperator(
@ -2976,7 +2976,7 @@ public class Attr extends JCTree.Visitor {
public void visitUnary(JCUnary tree) {
// Attribute arguments.
Type argtype = (tree.getTag().isIncOrDecUnaryOp())
? attribTree(tree.arg, env, varInfo)
? attribTree(tree.arg, env, varAssignmentInfo)
: chk.checkNonVoid(tree.arg.pos(), attribExpr(tree.arg, env));
// Find operator.
@ -3156,7 +3156,7 @@ public class Attr extends JCTree.Visitor {
// If we are expecting a variable (as opposed to a value), check
// that the variable is assignable in the current environment.
if (pkind() == KindSelector.VAR)
if (KindSelector.ASG.subset(pkind()))
checkAssignable(tree.pos(), v, null, env);
}
@ -3255,7 +3255,7 @@ public class Attr extends JCTree.Visitor {
// If we are expecting a variable (as opposed to a value), check
// that the variable is assignable in the current environment.
if (pkind() == KindSelector.VAR)
if (KindSelector.ASG.subset(pkind()))
checkAssignable(tree.pos(), v, tree.selected, env);
}
@ -3538,7 +3538,7 @@ public class Attr extends JCTree.Visitor {
// Test (4): if symbol is an instance field of a raw type,
// which is being assigned to, issue an unchecked warning if
// its type changes under erasure.
if (resultInfo.pkind == KindSelector.VAR &&
if (KindSelector.ASG.subset(pkind()) &&
v.owner.kind == TYP &&
(v.flags() & STATIC) == 0 &&
(site.hasTag(CLASS) || site.hasTag(TYPEVAR))) {

14
langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Flow.java
View file

@ -2562,6 +2562,8 @@ public class Flow {
* This pass implements the last step of the dataflow analysis, namely
* the effectively-final analysis check. This checks that every local variable
* reference from a lambda body/local inner class is either final or effectively final.
* Additional this also checks that every variable that is used as an operand to
* try-with-resources is final or effectively final.
* As effectively final variables are marked as such during DA/DU, this pass must run after
* AssignAnalyzer.
*/
@ -2690,6 +2692,18 @@ public class Flow {
}
}
public void visitTry(JCTry tree) {
for (JCTree resource : tree.resources) {
if (!resource.hasTag(VARDEF)) {
Symbol var = TreeInfo.symbol(resource);
if (var != null && (var.flags() & (FINAL | EFFECTIVELY_FINAL)) == 0) {
log.error(resource.pos(), "try.with.resources.expr.effectively.final.var", var);
}
}
}
super.visitTry(tree);
}
/**************************************************************************
* main method
*************************************************************************/

38
langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/parser/JavacParser.java
View file

@ -145,6 +145,8 @@ public class JavacParser implements Parser {
this.names = fac.names;
this.source = fac.source;
this.allowTWR = source.allowTryWithResources();
this.allowEffectivelyFinalVariablesInTWR =
source.allowEffectivelyFinalVariablesInTryWithResources();
this.allowDiamond = source.allowDiamond();
this.allowMulticatch = source.allowMulticatch();
this.allowStringFolding = fac.options.getBoolean("allowStringFolding", true);
@ -184,6 +186,10 @@ public class JavacParser implements Parser {
*/
boolean allowTWR;
/** Switch: should we allow (effectively) final variables as resources in try-with-resources?
*/
boolean allowEffectivelyFinalVariablesInTWR;
/** Switch: should we fold strings?
*/
boolean allowStringFolding;
@ -3003,14 +3009,28 @@ public class JavacParser implements Parser {
return defs.toList();
}
/** Resource = VariableModifiersOpt Type VariableDeclaratorId = Expression
/** Resource = VariableModifiersOpt Type VariableDeclaratorId "=" Expression
* | Expression
*/
protected JCTree resource() {
JCModifiers optFinal = optFinal(Flags.FINAL);
JCExpression type = parseType();
int pos = token.pos;
Name ident = ident();
return variableDeclaratorRest(pos, optFinal, type, ident, true, null);
int startPos = token.pos;
if (token.kind == FINAL || token.kind == MONKEYS_AT) {
JCModifiers mods = optFinal(Flags.FINAL);
JCExpression t = parseType();
return variableDeclaratorRest(token.pos, mods, t, ident(), true, null);
}
JCExpression t = term(EXPR | TYPE);
if ((lastmode & TYPE) != 0 && LAX_IDENTIFIER.accepts(token.kind)) {
JCModifiers mods = toP(F.at(startPos).Modifiers(Flags.FINAL));
return variableDeclaratorRest(token.pos, mods, t, ident(), true, null);
} else {
checkVariableInTryWithResources(startPos);
if (!t.hasTag(IDENT) && !t.hasTag(SELECT)) {
log.error(t.pos(), "try.with.resources.expr.needs.var");
}
return t;
}
}
/** CompilationUnit = [ { "@" Annotation } PACKAGE Qualident ";"] {ImportDeclaration} {TypeDeclaration}
@ -3933,6 +3953,12 @@ public class JavacParser implements Parser {
allowTWR = true;
}
}
void checkVariableInTryWithResources(int startPos) {
if (!allowEffectivelyFinalVariablesInTWR) {
error(startPos, "var.in.try.with.resources.not.supported.in.source", source.name);
allowEffectivelyFinalVariablesInTWR = true;
}
}
void checkLambda() {
if (!allowLambda) {
log.error(token.pos, "lambda.not.supported.in.source", source.name);

13
langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/resources/compiler.properties
View file

@ -252,6 +252,14 @@ compiler.err.cant.assign.val.to.final.var=\
compiler.err.cant.ref.non.effectively.final.var=\
local variables referenced from {1} must be final or effectively final
compiler.err.try.with.resources.expr.needs.var=\
the try-with-resources resource must either be a variable declaration or an expression denoting \
a reference to a final or effectively final variable
# 0: symbol
compiler.err.try.with.resources.expr.effectively.final.var=\
variable {0} used as a try-with-resources resource neither final nor effectively final
compiler.misc.lambda=\
a lambda expression
@ -2262,6 +2270,11 @@ compiler.err.try.with.resources.not.supported.in.source=\
try-with-resources is not supported in -source {0}\n\
(use -source 7 or higher to enable try-with-resources)
# 0: string
compiler.err.var.in.try.with.resources.not.supported.in.source=\
variables in try-with-resources not supported in -source {0}\n\
(use -source 9 or higher to enable variables in try-with-resources)
compiler.warn.underscore.as.identifier=\
''_'' used as an identifier\n\
(use of ''_'' as an identifier might not be supported in releases after Java SE 8)

2
langtools/test/tools/javac/TryWithResources/BadTwrSyntax.out
View file

@ -1,2 +1,2 @@
BadTwrSyntax.java:14:43: compiler.err.illegal.start.of.type
BadTwrSyntax.java:14:43: compiler.err.illegal.start.of.expr
1 error

5
langtools/test/tools/javac/TryWithResources/ResDeclOutsideTry.java
View file

@ -13,6 +13,11 @@ public class ResDeclOutsideTry implements AutoCloseable {
String test1() {
try (tr1 = new ResDeclOutsideTry(); tr2;) {
}
return null;
}
@Override
public void close() throws Exception {
}
}

5
langtools/test/tools/javac/TryWithResources/ResDeclOutsideTry.out
View file

@ -1,3 +1,2 @@
ResDeclOutsideTry.java:14:17: compiler.err.expected: token.identifier
ResDeclOutsideTry.java:14:48: compiler.err.expected: token.identifier
2 errors
ResDeclOutsideTry.java:14:18: compiler.err.try.with.resources.expr.needs.var
1 error

69
langtools/test/tools/javac/TryWithResources/TwrForVariable1.java Normal file
View file

@ -0,0 +1,69 @@
/* @test /nodynamiccopyright/
* @bug 7196163
* @summary Verify that variables can be used as operands to try-with-resources
* @compile/fail/ref=TwrForVariable1.out -source 8 -XDrawDiagnostics -Xlint:-options TwrForVariable1.java
* @compile TwrForVariable1.java
* @run main TwrForVariable1
*/
public class TwrForVariable1 implements AutoCloseable {
private static int closeCount = 0;
public static void main(String... args) {
TwrForVariable1 v = new TwrForVariable1();
try (v) {
assertCloseCount(0);
}
try (/**@deprecated*/v) {
assertCloseCount(1);
}
try (v.finalWrapper.finalField) {
assertCloseCount(2);
} catch (Exception ex) {
}
try (new TwrForVariable1() { }.finalWrapper.finalField) {
assertCloseCount(3);
} catch (Exception ex) {
}
try ((args.length > 0 ? v : new TwrForVariable1()).finalWrapper.finalField) {
assertCloseCount(4);
} catch (Exception ex) {
}
try {
throw new CloseableException();
} catch (CloseableException ex) {
try (ex) {
assertCloseCount(5);
}
}
assertCloseCount(6);
}
static void assertCloseCount(int expectedCloseCount) {
if (closeCount != expectedCloseCount)
throw new RuntimeException("bad closeCount: " + closeCount +
"; expected: " + expectedCloseCount);
}
public void close() {
closeCount++;
}
final FinalWrapper finalWrapper = new FinalWrapper();
static class FinalWrapper {
public final AutoCloseable finalField = new AutoCloseable() {
@Override
public void close() throws Exception {
closeCount++;
}
};
}
static class CloseableException extends Exception implements AutoCloseable {
@Override
public void close() {
closeCount++;
}
}
}

2
langtools/test/tools/javac/TryWithResources/TwrForVariable1.out Normal file
View file

@ -0,0 +1,2 @@
TwrForVariable1.java:13:14: compiler.err.var.in.try.with.resources.not.supported.in.source: 1.8
1 error

39
langtools/test/tools/javac/TryWithResources/TwrForVariable2.java Normal file
View file

@ -0,0 +1,39 @@
/* @test /nodynamiccopyright/
* @bug 7196163
* @summary Verify that an improper combination of modifiers and variable is rejected
* in an operand to try-with-resources
* @compile/fail/ref=TwrForVariable2.out -XDrawDiagnostics -Xlint:-options TwrForVariable2.java
*/
public class TwrForVariable2 implements AutoCloseable {
public static void main(String... args) {
TwrForVariable2 v = new TwrForVariable2();
TwrForVariable3[] v2 = new TwrForVariable3[1];
try (final v) {
fail("no modifiers before variables");
}
try (@Deprecated v) {
fail("no annotations before variables");
}
try (v;;) {
fail("illegal double semicolon");
}
try ((v)) {
fail("parentheses not allowed");
}
try (v2[0]) {
fail("array access not allowed");
}
try (args.length == 0 ? v : v) {
fail("general expressions not allowed");
}
}
static void fail(String reason) {
throw new RuntimeException(reason);
}
public void close() {
}
}

7
langtools/test/tools/javac/TryWithResources/TwrForVariable2.out Normal file
View file

@ -0,0 +1,7 @@
TwrForVariable2.java:12:21: compiler.err.expected: token.identifier
TwrForVariable2.java:15:27: compiler.err.expected: token.identifier
TwrForVariable2.java:18:16: compiler.err.illegal.start.of.expr
TwrForVariable2.java:21:14: compiler.err.try.with.resources.expr.needs.var
TwrForVariable2.java:24:16: compiler.err.try.with.resources.expr.needs.var
TwrForVariable2.java:27:31: compiler.err.try.with.resources.expr.needs.var
6 errors

29
langtools/test/tools/javac/TryWithResources/TwrForVariable3.java Normal file
View file

@ -0,0 +1,29 @@
/* @test /nodynamiccopyright/
* @bug 7196163
* @summary Verify that improper expressions used as an operand to try-with-resources are rejected.
* @compile/fail/ref=TwrForVariable3.out -XDrawDiagnostics -Xlint:-options TwrForVariable3.java
*/
public class TwrForVariable3 implements AutoCloseable {
public static void main(String... args) {
TwrForVariable3 v1 = new TwrForVariable3();
Object v2 = new Object();
try (v2) {
fail("no an AutoCloseable");
}
try (java.lang.Object) {
fail("not a variable access");
}
try (java.lang) {
fail("not a variable access");
}
}
static void fail(String reason) {
throw new RuntimeException(reason);
}
public void close() {
}
}

4
langtools/test/tools/javac/TryWithResources/TwrForVariable3.out Normal file
View file

@ -0,0 +1,4 @@
TwrForVariable3.java:11:14: compiler.err.prob.found.req: (compiler.misc.try.not.applicable.to.type: (compiler.misc.inconvertible.types: java.lang.Object, java.lang.AutoCloseable))
TwrForVariable3.java:14:18: compiler.err.cant.resolve.location: kindname.class, lang, , , (compiler.misc.location: kindname.package, java, null)
TwrForVariable3.java:17:14: compiler.err.cant.resolve.location: kindname.variable, java, , , (compiler.misc.location: kindname.class, TwrForVariable3, null)
3 errors

45
langtools/test/tools/javac/TryWithResources/TwrForVariable4.java Normal file
View file

@ -0,0 +1,45 @@
/* @test /nodynamiccopyright/
* @bug 7196163
* @summary Verify that variable used as an operand to try-with-resources is rejected if it is not
* definitelly assigned before use and or not final or effectivelly final.
* @compile/fail/ref=TwrForVariable4.out -XDrawDiagnostics -Xlint:-options TwrForVariable4.java
*/
public class TwrForVariable4 implements AutoCloseable {
public static void main(String... args) {
TwrForVariable4 uninitialized;
try (uninitialized) {
fail("must be initialized before use");
}
uninitialized = new TwrForVariable4();
TwrForVariable4 notEffectivellyFinal1 = new TwrForVariable4();
notEffectivellyFinal1 = new TwrForVariable4();
try (notEffectivellyFinal1) {
fail("not effectivelly final");
}
TwrForVariable4 notEffectivellyFinal2 = new TwrForVariable4();
try (notEffectivellyFinal2) {
notEffectivellyFinal2 = new TwrForVariable4();
fail("not effectivelly final");
}
try (notFinal) {
fail("not final");
}
}
static TwrForVariable4 notFinal = new TwrForVariable4();
static void fail(String reason) {
throw new RuntimeException(reason);
}
public void close() {
}
}

5
langtools/test/tools/javac/TryWithResources/TwrForVariable4.out Normal file
View file

@ -0,0 +1,5 @@
TwrForVariable4.java:11:14: compiler.err.var.might.not.have.been.initialized: uninitialized
TwrForVariable4.java:20:14: compiler.err.try.with.resources.expr.effectively.final.var: notEffectivellyFinal1
TwrForVariable4.java:26:14: compiler.err.try.with.resources.expr.effectively.final.var: notEffectivellyFinal2
TwrForVariable4.java:31:14: compiler.err.try.with.resources.expr.effectively.final.var: notFinal
4 errors

40
langtools/test/tools/javac/diags/examples/TryWithResourcesExprEffectivelyFinalVar.java Normal file
View file

@ -0,0 +1,40 @@
/*
* Copyright (c) 2014, 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.
*/
// key: compiler.err.try.with.resources.expr.effectively.final.var
class TryWithResourcesExprEffectivelyFinalVar {
void m() {
CloseableImpl ac = new CloseableImpl();
try (ac) {
ac = null;
}
}
}
class CloseableImpl implements AutoCloseable {
@Override
public void close() {
}
}

37
langtools/test/tools/javac/diags/examples/TryWithResourcesExprNeedsVar.java Normal file
View file

@ -0,0 +1,37 @@
/*
* Copyright (c) 2014, 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.
*/
// key: compiler.err.try.with.resources.expr.needs.var
class TryWithResourcesExprNeedsVar {
void m() {
try (new CloseableImpl()) {
}
}
}
class CloseableImpl implements AutoCloseable {
@Override
public void close() throws Exception {
}
}

41
langtools/test/tools/javac/diags/examples/VarInTryWithResourcesNotSupportedInSource.java Normal file
View file

@ -0,0 +1,41 @@
/*
* Copyright (c) 2014, 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.
*/
// key: compiler.err.var.in.try.with.resources.not.supported.in.source
// key: compiler.warn.source.no.bootclasspath
// options: -source 8
class VarInTryWithResourcesNotSupportedInSource {
void m() {
AutoCloseable ac = new CloseableImpl();
try (ac) {
}
}
}
class CloseableImpl implements AutoCloseable {
@Override
public void close() throws Exception {
}
}