/*
* Copyright 2000-2016 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jetbrains.plugins.groovy.codeInspection.noReturnMethod;
import com.intellij.codeInspection.ProblemsHolder;
import com.intellij.openapi.util.Pair;
import com.intellij.openapi.util.Ref;
import com.intellij.openapi.util.TextRange;
import com.intellij.psi.*;
import org.jetbrains.annotations.Nls;
import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.jetbrains.plugins.groovy.codeInspection.GroovyInspectionBundle;
import org.jetbrains.plugins.groovy.codeInspection.GroovySuppressableInspectionTool;
import org.jetbrains.plugins.groovy.codeInspection.utils.ControlFlowUtils;
import org.jetbrains.plugins.groovy.lang.psi.GrControlFlowOwner;
import org.jetbrains.plugins.groovy.lang.psi.GroovyElementVisitor;
import org.jetbrains.plugins.groovy.lang.psi.GroovyPsiElementVisitor;
import org.jetbrains.plugins.groovy.lang.psi.api.GroovyResolveResult;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.arguments.GrArgumentList;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.blocks.GrClosableBlock;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.blocks.GrCodeBlock;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.blocks.GrOpenBlock;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.branch.GrReturnStatement;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.expressions.GrExpression;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.expressions.GrMethodCall;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.typedef.members.GrMethod;
import org.jetbrains.plugins.groovy.lang.psi.controlFlow.Instruction;
import org.jetbrains.plugins.groovy.lang.psi.controlFlow.impl.MaybeReturnInstruction;
import org.jetbrains.plugins.groovy.lang.psi.controlFlow.impl.ThrowingInstruction;
import org.jetbrains.plugins.groovy.lang.psi.expectedTypes.GroovyExpectedTypesProvider;
import org.jetbrains.plugins.groovy.lang.psi.impl.signatures.GrClosureSignatureUtil;
import org.jetbrains.plugins.groovy.lang.psi.impl.statements.expressions.TypesUtil;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
/**
* @author ven
*/
public class MissingReturnInspection extends GroovySuppressableInspectionTool {
@Override
@Nls
@NotNull
public String getGroupDisplayName() {
return GroovyInspectionBundle.message("groovy.dfa.issues");
}
@NotNull
@Override
public String[] getGroupPath() {
return new String[]{"Groovy", getGroupDisplayName()};
}
@Override
@Nls
@NotNull
public String getDisplayName() {
return GroovyInspectionBundle.message("no.return.display.name");
}
public enum ReturnStatus {
mustReturnValue, shouldReturnValue, shouldNotReturnValue;
public static ReturnStatus getReturnStatus(PsiElement subject) {
if (subject instanceof GrClosableBlock) {
final PsiType inferredReturnType = getExpectedClosureReturnType((GrClosableBlock)subject);
if (inferredReturnType instanceof PsiClassType) {
PsiClass resolved = ((PsiClassType)inferredReturnType).resolve();
if (resolved != null && !(resolved instanceof PsiTypeParameter)) return mustReturnValue;
}
return inferredReturnType != null && !PsiType.VOID.equals(inferredReturnType) ? shouldReturnValue : shouldNotReturnValue;
}
else if (subject instanceof GrMethod) {
return ((GrMethod)subject).getReturnTypeElementGroovy() != null && !PsiType.VOID.equals(((GrMethod)subject).getReturnType())
? mustReturnValue
: shouldNotReturnValue;
}
return shouldNotReturnValue;
}
}
@Nullable
public static PsiType getExpectedClosureReturnType(GrClosableBlock closure) {
List<PsiType> expectedReturnTypes = new ArrayList<>();
PsiElement parent = closure.getParent();
if (parent instanceof GrArgumentList && parent.getParent() instanceof GrMethodCall || parent instanceof GrMethodCall) {
GrMethodCall call = (GrMethodCall)(parent instanceof GrArgumentList ? parent.getParent() : parent);
GroovyResolveResult[] variants = call.getCallVariants(null);
for (GroovyResolveResult variant : variants) {
Map<GrExpression,Pair<PsiParameter,PsiType>> map =
GrClosureSignatureUtil.mapArgumentsToParameters(variant, closure, true, true, call.getNamedArguments(), call.getExpressionArguments(), call.getClosureArguments());
if (map != null) {
Pair<PsiParameter, PsiType> pair = map.get(closure);
if (pair == null) continue;
PsiParameter parameter = pair.getFirst();
PsiType type = parameter.getType();
if (TypesUtil.isPsiClassTypeToClosure(type)) {
PsiType[] parameters = ((PsiClassType)type).getParameters();
if (parameters.length == 1) {
expectedReturnTypes.add(parameters[0]);
}
}
}
}
}
else {
for (PsiType expectedType : GroovyExpectedTypesProvider.getDefaultExpectedTypes(closure)) {
if (TypesUtil.isPsiClassTypeToClosure(expectedType)) {
PsiType[] parameters = ((PsiClassType)expectedType).getParameters();
if (parameters.length == 1) {
expectedReturnTypes.add(parameters[0]);
}
}
}
}
for (PsiType type : expectedReturnTypes) {
if (PsiType.VOID.equals(type)) return PsiType.VOID;
}
return TypesUtil.getLeastUpperBoundNullable(expectedReturnTypes, closure.getManager());
}
@Override
@NotNull
public PsiElementVisitor buildVisitor(@NotNull final ProblemsHolder problemsHolder, boolean onTheFly) {
return new GroovyPsiElementVisitor(new GroovyElementVisitor() {
@Override
public void visitClosure(@NotNull GrClosableBlock closure) {
super.visitClosure(closure);
check(closure, problemsHolder, ReturnStatus.getReturnStatus(closure));
}
@Override
public void visitMethod(@NotNull GrMethod method) {
super.visitMethod(method);
final GrOpenBlock block = method.getBlock();
if (block != null) {
check(block, problemsHolder, ReturnStatus.getReturnStatus(method));
}
}
});
}
private static void check(GrCodeBlock block, ProblemsHolder holder, ReturnStatus returnStatus) {
if (methodMissesSomeReturns(block, returnStatus)) {
addNoReturnMessage(block, holder);
}
}
public static boolean methodMissesSomeReturns(@NotNull GrControlFlowOwner block, @NotNull final ReturnStatus returnStatus) {
if (returnStatus == ReturnStatus.shouldNotReturnValue) {
return false;
}
final Ref<Boolean> alwaysHaveReturn = new Ref<>(true);
final Ref<Boolean> sometimesHaveReturn = new Ref<>(false);
final Ref<Boolean> hasExplicitReturn = new Ref<>(false);
ControlFlowUtils.visitAllExitPoints(block, new ControlFlowUtils.ExitPointVisitor() {
@Override
public boolean visitExitPoint(Instruction instruction, @Nullable GrExpression returnValue) {
//don't modify sometimesHaveReturn in this case:
// def foo() {
// if (cond) throw new RuntimeException()
// }
if (instruction instanceof ThrowingInstruction) {
if (returnStatus == ReturnStatus.mustReturnValue) {
sometimesHaveReturn.set(true);
}
return true;
}
if (instruction instanceof MaybeReturnInstruction && ((MaybeReturnInstruction)instruction).mayReturnValue()) {
sometimesHaveReturn.set(true);
return true;
}
if (instruction.getElement() instanceof GrReturnStatement && returnValue != null) {
sometimesHaveReturn.set(true);
hasExplicitReturn.set(true);
return true;
}
alwaysHaveReturn.set(false);
return true;
}
});
if (returnStatus == ReturnStatus.mustReturnValue && !sometimesHaveReturn.get()) {
return true;
}
return sometimesHaveReturn.get() && !alwaysHaveReturn.get();
}
private static void addNoReturnMessage(GrCodeBlock block, ProblemsHolder holder) {
final PsiElement lastChild = block.getLastChild();
if (lastChild == null) return;
TextRange range = lastChild.getTextRange();
if (!lastChild.isValid() || !lastChild.isPhysical() || range.getStartOffset() >= range.getEndOffset()) {
return;
}
holder.registerProblem(lastChild, GroovyInspectionBundle.message("no.return.message"));
}
@Override
@NonNls
@NotNull
public String getShortName() {
return "GroovyMissingReturnStatement";
}
@Override
public boolean isEnabledByDefault() {
return true;
}
}