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Add "Redundant nullable return type" inspection

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^KT-19321 Fixed
This commit is contained in:
Toshiaki Kameyama
2020-08-16 01:06:20 +02:00
committed by Vladimir Dolzhenko
parent d703284d01
commit 8420c0b7c7
23 changed files with 297 additions and 0 deletions
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idea/resources-en/inspectionDescriptions/RedundantNullableReturnType.html
+5
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@@ -0,0 +1,5 @@
<html>
<body>
This inspections reports functions/variables with nullable return type always returns non-null.
</body>
</html>
idea/resources-en/messages/KotlinBundle.properties
+3
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@@ -2261,6 +2261,9 @@ redundant.qualifier.unnecessary.non.direct.parent.class.qualifier=Unnecessary no
fix.add.exception.to.throws=Add ''{0}'' fix.add.exception.to.throws=Add ''{0}''
fix.add.eq.eq.true=Add '== true' fix.add.eq.eq.true=Add '== true'
inspection.replace.with.ignore.case.equals.display.name=Replace with 'equals(..., ignoreCase = true)' inspection.replace.with.ignore.case.equals.display.name=Replace with 'equals(..., ignoreCase = true)'
inspection.redundant.nullable.return.type.display.name=Redundant nullable return type
0.always.returns.non.null.type=''{0}'' always returns non-null type
0.is.always.non.null.type=''{0}'' is always non-null type
inspection.simplifiable.scope.function.display.name=Scope function with nested forEach can be simplified inspection.simplifiable.scope.function.display.name=Scope function with nested forEach can be simplified
nested.1.call.in.0.could.be.simplified.to.2=Nested ''{1}'' call in ''{0}'' could be simplified to {2} nested.1.call.in.0.could.be.simplified.to.2=Nested ''{1}'' call in ''{0}'' could be simplified to {2}
idea/resources/META-INF/inspections.xml
+10
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@@ -2550,6 +2550,15 @@
level="WEAK WARNING" level="WEAK WARNING"
language="kotlin" language="kotlin"
key="inspection.replace.with.ignore.case.equals.display.name" bundle="messages.KotlinBundle"/> key="inspection.replace.with.ignore.case.equals.display.name" bundle="messages.KotlinBundle"/>
<localInspection implementationClass="org.jetbrains.kotlin.idea.inspections.RedundantNullableReturnTypeInspection"
groupPath="Kotlin"
groupName="Redundant constructs"
enabledByDefault="true"
level="WARNING"
language="kotlin"
key="inspection.redundant.nullable.return.type.display.name" bundle="messages.KotlinBundle"/>
<localInspection implementationClass="org.jetbrains.kotlin.idea.inspections.SimplifyNestedEachInScopeFunctionInspection" <localInspection implementationClass="org.jetbrains.kotlin.idea.inspections.SimplifyNestedEachInScopeFunctionInspection"
groupPath="Kotlin" groupPath="Kotlin"
groupName="Style issues" groupName="Style issues"
@@ -2557,6 +2566,7 @@
level="WEAK WARNING" level="WEAK WARNING"
language="kotlin" language="kotlin"
key="inspection.simplifiable.scope.function.display.name" bundle="messages.KotlinBundle"/> key="inspection.simplifiable.scope.function.display.name" bundle="messages.KotlinBundle"/>
</extensions> </extensions>
</idea-plugin> </idea-plugin>
idea/src/org/jetbrains/kotlin/idea/inspections/RedundantNullableReturnTypeInspection.kt
+112
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@@ -0,0 +1,112 @@
/*
* Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
* Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
*/
package org.jetbrains.kotlin.idea.inspections
import com.intellij.codeInspection.LocalQuickFix
import com.intellij.codeInspection.ProblemDescriptor
import com.intellij.codeInspection.ProblemsHolder
import com.intellij.openapi.project.Project
import com.intellij.psi.impl.source.tree.LeafPsiElement
import org.jetbrains.kotlin.config.LanguageVersionSettings
import org.jetbrains.kotlin.descriptors.ModuleDescriptor
import org.jetbrains.kotlin.idea.KotlinBundle
import org.jetbrains.kotlin.idea.caches.resolve.analyze
import org.jetbrains.kotlin.idea.caches.resolve.findModuleDescriptor
import org.jetbrains.kotlin.idea.caches.resolve.getResolutionFacade
import org.jetbrains.kotlin.idea.core.isOverridable
import org.jetbrains.kotlin.idea.project.languageVersionSettings
import org.jetbrains.kotlin.idea.resolve.getDataFlowValueFactory
import org.jetbrains.kotlin.idea.util.textRangeIn
import org.jetbrains.kotlin.psi.*
import org.jetbrains.kotlin.psi.psiUtil.collectDescendantsOfType
import org.jetbrains.kotlin.resolve.BindingContext
import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValueFactory
import org.jetbrains.kotlin.types.KotlinType
import org.jetbrains.kotlin.types.isNullable
class RedundantNullableReturnTypeInspection : AbstractKotlinInspection() {
override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean) = object : KtVisitorVoid() {
override fun visitNamedFunction(function: KtNamedFunction) {
check(function)
}
override fun visitProperty(property: KtProperty) {
if (property.isVar) return
check(property)
}
private fun check(declaration: KtCallableDeclaration) {
val typeReference = declaration.typeReference ?: return
val typeElement = typeReference.typeElement as? KtNullableType ?: return
if (typeElement.innerType == null) return
val questionMark = typeElement.questionMarkNode as? LeafPsiElement ?: return
if (declaration.isOverridable()) return
val body = when (declaration) {
is KtNamedFunction -> declaration.bodyExpression
is KtProperty -> declaration.initializer ?: declaration.accessors.singleOrNull { it.isGetter }?.bodyExpression
else -> null
} ?: return
val actualReturnTypes = body.actualReturnTypes()
if (actualReturnTypes.isEmpty() || actualReturnTypes.any { it.isNullable() }) return
val declarationName = declaration.nameAsSafeName.asString()
val description = if (declaration is KtProperty) {
KotlinBundle.message("0.is.always.non.null.type", declarationName)
} else {
KotlinBundle.message("0.always.returns.non.null.type", declarationName)
}
holder.registerProblem(
typeReference,
questionMark.textRangeIn(typeReference),
description,
MakeNotNullableFix()
)
}
}
private fun KtExpression.actualReturnTypes(): List<KotlinType> {
val context = analyze()
val dataFlowValueFactory = getResolutionFacade().getDataFlowValueFactory()
val moduleDescriptor = findModuleDescriptor()
val languageVersionSettings = languageVersionSettings
return if (this is KtBlockExpression) {
collectDescendantsOfType<KtReturnExpression>().flatMap {
it.returnedExpression.types(context, dataFlowValueFactory, moduleDescriptor, languageVersionSettings)
}
} else {
types(context, dataFlowValueFactory, moduleDescriptor, languageVersionSettings)
}
}
private fun KtExpression?.types(
context: BindingContext,
dataFlowValueFactory: DataFlowValueFactory,
moduleDescriptor: ModuleDescriptor,
languageVersionSettings: LanguageVersionSettings
): List<KotlinType> {
if (this == null) return emptyList()
val type = context.getType(this) ?: return emptyList()
val dataFlowInfo = context[BindingContext.EXPRESSION_TYPE_INFO, this]?.dataFlowInfo ?: return emptyList()
val dataFlowValue = dataFlowValueFactory.createDataFlowValue(this, type, context, moduleDescriptor)
val stableTypes = dataFlowInfo.getStableTypes(dataFlowValue, languageVersionSettings)
return if (stableTypes.isNotEmpty()) stableTypes.toList() else listOf(type)
}
private class MakeNotNullableFix : LocalQuickFix {
override fun getName() = KotlinBundle.message("make.not.nullable")
override fun getFamilyName() = name
override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
val typeReference = descriptor.psiElement as? KtTypeReference ?: return
val typeElement = typeReference.typeElement as? KtNullableType ?: return
val innerType = typeElement.innerType ?: return
typeElement.replace(innerType)
}
}
}
idea/testData/inspectionsLocal/redundantNullableReturnType/.inspection
Vendored
+1
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@@ -0,0 +1 @@
org.jetbrains.kotlin.idea.inspections.RedundantNullableReturnTypeInspection
idea/testData/inspectionsLocal/redundantNullableReturnType/function/blockBody.kt
Vendored
+5
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@@ -0,0 +1,5 @@
// PROBLEM: 'foo' always returns non-null type
// WITH_RUNTIME
fun foo(xs: List<Int>): Int?<caret> {
return xs.first()
}
idea/testData/inspectionsLocal/redundantNullableReturnType/function/blockBody.kt.after
Vendored
+5
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@@ -0,0 +1,5 @@
// PROBLEM: 'foo' always returns non-null type
// WITH_RUNTIME
fun foo(xs: List<Int>): Int {
return xs.first()
}
idea/testData/inspectionsLocal/redundantNullableReturnType/function/blockBodyReturnsNullable.kt
Vendored
+9
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@@ -0,0 +1,9 @@
// PROBLEM: none
// WITH_RUNTIME
fun foo(xs: List<Int>, b: Boolean): Int?<caret> {
if (b) {
return xs.first()
} else {
return xs.lastOrNull()
}
}
idea/testData/inspectionsLocal/redundantNullableReturnType/function/blockBodyWithSmartCast.kt
Vendored
+8
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@@ -0,0 +1,8 @@
// PROBLEM: 'foo' always returns non-null type
fun foo(i: Int?): Int?<caret> {
if (i != null) {
return i
} else {
return 0
}
}
idea/testData/inspectionsLocal/redundantNullableReturnType/function/blockBodyWithSmartCast.kt.after
Vendored
+8
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@@ -0,0 +1,8 @@
// PROBLEM: 'foo' always returns non-null type
fun foo(i: Int?): Int {
if (i != null) {
return i
} else {
return 0
}
}
idea/testData/inspectionsLocal/redundantNullableReturnType/function/notNullableReturnType.kt
Vendored
+2
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@@ -0,0 +1,2 @@
// PROBLEM: none
fun foo(): String<caret> = ""
idea/testData/inspectionsLocal/redundantNullableReturnType/function/overridable.kt
Vendored
+4
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@@ -0,0 +1,4 @@
// PROBLEM: none
abstract class Foo {
open fun foo(): String?<caret> = ""
}
idea/testData/inspectionsLocal/redundantNullableReturnType/function/singleExpressionBody.kt
Vendored
+3
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@@ -0,0 +1,3 @@
// PROBLEM: 'foo' always returns non-null type
// WITH_RUNTIME
fun foo(xs: List<Int>): Int?<caret> = xs.first()
idea/testData/inspectionsLocal/redundantNullableReturnType/function/singleExpressionBody.kt.after
Vendored
+3
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@@ -0,0 +1,3 @@
// PROBLEM: 'foo' always returns non-null type
// WITH_RUNTIME
fun foo(xs: List<Int>): Int = xs.first()
idea/testData/inspectionsLocal/redundantNullableReturnType/function/singleExpressionBodyReturnsNullable.kt
Vendored
+3
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@@ -0,0 +1,3 @@
// PROBLEM: none
// WITH_RUNTIME
fun foo(xs: List<Int>, b: Boolean): Int?<caret> = if (b) xs.first() else xs.lastOrNull()
idea/testData/inspectionsLocal/redundantNullableReturnType/property/getter.kt
Vendored
+3
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@@ -0,0 +1,3 @@
// PROBLEM: 'foo' is always non-null type
val foo: Int?<caret>
get() = 1
idea/testData/inspectionsLocal/redundantNullableReturnType/property/getter.kt.after
Vendored
+3
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@@ -0,0 +1,3 @@
// PROBLEM: 'foo' is always non-null type
val foo: Int
get() = 1
idea/testData/inspectionsLocal/redundantNullableReturnType/property/getterWithBody.kt
Vendored
+5
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@@ -0,0 +1,5 @@
// PROBLEM: 'foo' is always non-null type
val foo: Int?<caret>
get() {
return 1
}
idea/testData/inspectionsLocal/redundantNullableReturnType/property/getterWithBody.kt.after
Vendored
+5
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@@ -0,0 +1,5 @@
// PROBLEM: 'foo' is always non-null type
val foo: Int
get() {
return 1
}
idea/testData/inspectionsLocal/redundantNullableReturnType/property/initializer.kt
Vendored
+2
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@@ -0,0 +1,2 @@
// PROBLEM: 'foo' is always non-null type
val foo: String?<caret> = ""
idea/testData/inspectionsLocal/redundantNullableReturnType/property/initializer.kt.after
Vendored
+2
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@@ -0,0 +1,2 @@
// PROBLEM: 'foo' is always non-null type
val foo: String = ""
idea/testData/inspectionsLocal/redundantNullableReturnType/property/var.kt
Vendored
+2
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@@ -0,0 +1,2 @@
// PROBLEM: none
var foo: String?<caret> = ""
idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java
Generated
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@@ -8218,6 +8218,100 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
} }
} }
@TestMetadata("idea/testData/inspectionsLocal/redundantNullableReturnType")
@TestDataPath("$PROJECT_ROOT")
@RunWith(JUnit3RunnerWithInners.class)
public static class RedundantNullableReturnType extends AbstractLocalInspectionTest {
private void runTest(String testDataFilePath) throws Exception {
KotlinTestUtils.runTest(this::doTest, this, testDataFilePath);
}
public void testAllFilesPresentInRedundantNullableReturnType() throws Exception {
KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("idea/testData/inspectionsLocal/redundantNullableReturnType"), Pattern.compile("^([\\w\\-_]+)\\.(kt|kts)$"), null, true);
}
@TestMetadata("idea/testData/inspectionsLocal/redundantNullableReturnType/function")
@TestDataPath("$PROJECT_ROOT")
@RunWith(JUnit3RunnerWithInners.class)
public static class Function extends AbstractLocalInspectionTest {
private void runTest(String testDataFilePath) throws Exception {
KotlinTestUtils.runTest(this::doTest, this, testDataFilePath);
}
public void testAllFilesPresentInFunction() throws Exception {
KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("idea/testData/inspectionsLocal/redundantNullableReturnType/function"), Pattern.compile("^([\\w\\-_]+)\\.(kt|kts)$"), null, true);
}
@TestMetadata("blockBody.kt")
public void testBlockBody() throws Exception {
runTest("idea/testData/inspectionsLocal/redundantNullableReturnType/function/blockBody.kt");
}
@TestMetadata("blockBodyReturnsNullable.kt")
public void testBlockBodyReturnsNullable() throws Exception {
runTest("idea/testData/inspectionsLocal/redundantNullableReturnType/function/blockBodyReturnsNullable.kt");
}
@TestMetadata("blockBodyWithSmartCast.kt")
public void testBlockBodyWithSmartCast() throws Exception {
runTest("idea/testData/inspectionsLocal/redundantNullableReturnType/function/blockBodyWithSmartCast.kt");
}
@TestMetadata("notNullableReturnType.kt")
public void testNotNullableReturnType() throws Exception {
runTest("idea/testData/inspectionsLocal/redundantNullableReturnType/function/notNullableReturnType.kt");
}
@TestMetadata("overridable.kt")
public void testOverridable() throws Exception {
runTest("idea/testData/inspectionsLocal/redundantNullableReturnType/function/overridable.kt");
}
@TestMetadata("singleExpressionBody.kt")
public void testSingleExpressionBody() throws Exception {
runTest("idea/testData/inspectionsLocal/redundantNullableReturnType/function/singleExpressionBody.kt");
}
@TestMetadata("singleExpressionBodyReturnsNullable.kt")
public void testSingleExpressionBodyReturnsNullable() throws Exception {
runTest("idea/testData/inspectionsLocal/redundantNullableReturnType/function/singleExpressionBodyReturnsNullable.kt");
}
}
@TestMetadata("idea/testData/inspectionsLocal/redundantNullableReturnType/property")
@TestDataPath("$PROJECT_ROOT")
@RunWith(JUnit3RunnerWithInners.class)
public static class Property extends AbstractLocalInspectionTest {
private void runTest(String testDataFilePath) throws Exception {
KotlinTestUtils.runTest(this::doTest, this, testDataFilePath);
}
public void testAllFilesPresentInProperty() throws Exception {
KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("idea/testData/inspectionsLocal/redundantNullableReturnType/property"), Pattern.compile("^([\\w\\-_]+)\\.(kt|kts)$"), null, true);
}
@TestMetadata("getter.kt")
public void testGetter() throws Exception {
runTest("idea/testData/inspectionsLocal/redundantNullableReturnType/property/getter.kt");
}
@TestMetadata("getterWithBody.kt")
public void testGetterWithBody() throws Exception {
runTest("idea/testData/inspectionsLocal/redundantNullableReturnType/property/getterWithBody.kt");
}
@TestMetadata("initializer.kt")
public void testInitializer() throws Exception {
runTest("idea/testData/inspectionsLocal/redundantNullableReturnType/property/initializer.kt");
}
@TestMetadata("var.kt")
public void testVar() throws Exception {
runTest("idea/testData/inspectionsLocal/redundantNullableReturnType/property/var.kt");
}
}
}
@TestMetadata("idea/testData/inspectionsLocal/redundantObjectTypeCheck") @TestMetadata("idea/testData/inspectionsLocal/redundantObjectTypeCheck")
@TestDataPath("$PROJECT_ROOT") @TestDataPath("$PROJECT_ROOT")
@RunWith(JUnit3RunnerWithInners.class) @RunWith(JUnit3RunnerWithInners.class)