Java to Kotlin converter: more smartness about nullability

2014-06-06 21:26:25 +04:00
parent e947ad7294
commit 0695f6b3d7
18 changed files with 143 additions and 10 deletions
@@ -218,7 +218,7 @@ public class Converter(val project: Project, val settings: ConverterSettings) {
                     typeConverter.convertVariableType(field),
                     convertExpression(field.getInitializer(), field.getType()),
                     field.hasModifierProperty(PsiModifier.FINAL),
-                     field.countWriteAccesses(field.getContainingClass()))
+                     field.hasWriteAccesses(field.getContainingClass()))
    }

    private fun convertMethod(method: PsiMethod, membersToRemove: MutableSet<PsiMember>): Function {
@@ -44,7 +44,7 @@ class TypeConverter(val settings: ConverterSettings) {
            val initializer = variable.getInitializer()
            if (initializer != null) {
                val initializerNullability = initializer.nullability()
-                if (variable.hasModifierProperty(PsiModifier.FINAL)) { //TODO: replace check for final modifier with effective final
+                if (variable.isEffectivelyFinal()) {
                    nullability = initializerNullability
                }
                else if (initializerNullability == Nullability.Nullable) { // if variable is not final then non-nullability of initializer does not mean that variable is non-null
@@ -159,6 +159,19 @@ class TypeConverter(val settings: ConverterSettings) {
                return otherOperand is PsiLiteralExpression && otherOperand.getType() == PsiType.NULL
            }
        }
+        else if (parent is PsiVariable && usage == parent.getInitializer() && parent.isEffectivelyFinal()) {
+            return convertVariableType(parent).isNullable
+        }
        return false
    }
+
+    private fun PsiVariable.isEffectivelyFinal(): Boolean {
+        if (hasModifierProperty(PsiModifier.FINAL)) return true
+        return when(this) {
+            is PsiLocalVariable -> !hasWriteAccesses(getContainingMethod())
+            is PsiField -> if (hasModifierProperty(PsiModifier.PRIVATE)) !hasWriteAccesses(getContainingClass()) else false
+            is PsiParameter -> true
+            else -> false
+        }
+    }
 }
@@ -46,6 +46,9 @@ fun findMethodCalls(method: PsiMethod, scope: PsiElement): Collection<PsiMethodC
 fun PsiVariable.countWriteAccesses(scope: PsiElement?): Int
        = if (scope != null) findVariableUsages(this, scope).count { PsiUtil.isAccessedForWriting(it) } else 0

+fun PsiVariable.hasWriteAccesses(scope: PsiElement?): Boolean
+        = if (scope != null) findVariableUsages(this, scope).any { PsiUtil.isAccessedForWriting(it) } else false
+
 fun PsiModifierListOwner.nullabilityFromAnnotations(): Nullability {
    val annotations = getModifierList()?.getAnnotations() ?: return Nullability.Default
    return if (annotations.any { NOT_NULL_ANNOTATIONS.contains(it.getQualifiedName()) })
@@ -22,7 +22,7 @@ class EnumConstant(
        modifiers: Set<Modifier>,
        `type`: Type,
        params: Element
-) : Field(identifier, members, modifiers, `type`.toNotNullType(), params, true, 0) {
+) : Field(identifier, members, modifiers, `type`.toNotNullType(), params, true, false) {

    override fun toKotlin(): String {
        if (initializer.toKotlin().isEmpty()) {
@@ -26,13 +26,13 @@ open class Field(
        val `type`: Type,
        val initializer: Element,
        val isVal: Boolean,
-        val writingAccesses: Int
+        private val hasWriteAccesses: Boolean
 ) : Member(comments, modifiers) {

    override fun toKotlin(): String {
        val declaration = commentsToKotlin() + modifiersToKotlin() + (if (isVal) "val " else "var ") + identifier.toKotlin() + " : " + `type`.toKotlin()
        return if (initializer.isEmpty)
-            declaration + (if (isVal && !isStatic() && writingAccesses != 0) "" else " = " + getDefaultInitializer(this))
+            declaration + (if (isVal && !isStatic() && hasWriteAccesses) "" else " = " + getDefaultInitializer(this))
        else
            declaration + " = " + initializer.toKotlin()
    }
@@ -21,6 +21,7 @@ import org.jetbrains.jet.j2k.Converter
 import org.jetbrains.jet.j2k.ast.*
 import org.jetbrains.jet.j2k.countWriteAccesses
 import java.util.ArrayList
+import org.jetbrains.jet.j2k.hasWriteAccesses

 class StatementVisitor(public val converter: Converter) : JavaElementVisitor() {
    public var result: Statement = Statement.Empty
@@ -82,8 +83,8 @@ class StatementVisitor(public val converter: Converter) : JavaElementVisitor() {

        val loopVar = initialization?.getFirstChild() as? PsiLocalVariable
        val onceWritableIterator = loopVar != null
-                && loopVar.countWriteAccesses(body) == 0
-                && loopVar.countWriteAccesses(condition) == 0
+                && !loopVar.hasWriteAccesses(body)
+                && !loopVar.hasWriteAccesses(condition)
                && loopVar.countWriteAccesses(update) == 1

        val operationTokenType = (condition as? PsiBinaryExpression)?.getOperationTokenType()
@@ -1926,6 +1926,26 @@ public class JavaToKotlinConverterTestGenerated extends AbstractJavaToKotlinConv
            doTest("j2k/tests/testData/ast/nullability/MethodResultComparedWithNull.java");
        }
        
+        @TestMetadata("MethodResultComparedWithNull2.java")
+        public void testMethodResultComparedWithNull2() throws Exception {
+            doTest("j2k/tests/testData/ast/nullability/MethodResultComparedWithNull2.java");
+        }
+        
+        @TestMetadata("MethodResultComparedWithNull3.java")
+        public void testMethodResultComparedWithNull3() throws Exception {
+            doTest("j2k/tests/testData/ast/nullability/MethodResultComparedWithNull3.java");
+        }
+        
+        @TestMetadata("MethodResultComparedWithNull4.java")
+        public void testMethodResultComparedWithNull4() throws Exception {
+            doTest("j2k/tests/testData/ast/nullability/MethodResultComparedWithNull4.java");
+        }
+        
+        @TestMetadata("MethodResultInitializesNullableField.java")
+        public void testMethodResultInitializesNullableField() throws Exception {
+            doTest("j2k/tests/testData/ast/nullability/MethodResultInitializesNullableField.java");
+        }
+        
        @TestMetadata("MethodReturnsNull.java")
        public void testMethodReturnsNull() throws Exception {
            doTest("j2k/tests/testData/ast/nullability/MethodReturnsNull.java");
@@ -11,7 +11,7 @@ class Library() {

 class User() {
    fun main() {
-        val lib: Library? = Library()
+        val lib: Library = Library()
        lib?.call()
        lib?.getString()?.isEmpty()

@@ -1,6 +1,6 @@
 //file
 class C {
-    private String s = "";
+    private String s = x();

    void foo() {
        if (s == null) {
@@ -1,5 +1,5 @@
 class C() {
-    private var s: String? = ""
+    private var s: String? = x()

    fun foo() {
        if (s == null) {
@@ -0,0 +1,13 @@
+//file
+interface I {
+    String getString();
+}
+
+class C {
+    void foo(I i) {
+        final String result = i.getString();
+        if (result != null) {
+            print(result);
+        }
+    }
+}
@@ -0,0 +1,12 @@
+trait I {
+    public fun getString(): String?
+}
+
+class C() {
+    fun foo(i: I) {
+        val result = i.getString()
+        if (result != null) {
+            print(result)
+        }
+    }
+}
@@ -0,0 +1,13 @@
+//file
+interface I {
+    String getString();
+}
+
+class C {
+    void foo(I i) {
+        String result = i.getString();
+        if (result != null) {
+            print(result);
+        }
+    }
+}
@@ -0,0 +1,12 @@
+trait I {
+    public fun getString(): String?
+}
+
+class C() {
+    fun foo(i: I) {
+        val result = i.getString()
+        if (result != null) {
+            print(result)
+        }
+    }
+}
@@ -0,0 +1,14 @@
+//file
+interface I {
+    String getString();
+}
+
+class C {
+    void foo(I i, boolean b) {
+        String result = i.getString();
+        if (b) result = null;
+        if (result != null) {
+            print(result);
+        }
+    }
+}
@@ -0,0 +1,14 @@
+trait I {
+    public fun getString(): String
+}
+
+class C() {
+    fun foo(i: I, b: Boolean) {
+        val result = i.getString()
+        if (b)
+            result = null
+        if (result != null) {
+            print(result)
+        }
+    }
+}
@@ -0,0 +1,8 @@
+//file
+import org.jetbrains.annotations.Nullable;
+
+class C {
+    @Nullable private final String string = getString();
+
+    static String getString() { return x(); }
+}
@@ -0,0 +1,10 @@
+class C() {
+    private val string: String? = getString()
+
+    class object {
+
+        fun getString(): String? {
+            return x()
+        }
+    }
+}