J2K: Get nullability from variable initializer when converting call

#KT-11534 In Progress

idea/src/org/jetbrains/kotlin/idea/j2k/J2kPostProcessor.kt

@@ -21,6 +21,8 @@ import com.intellij.openapi.util.TextRange
 import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiRecursiveElementVisitor
 import com.intellij.psi.codeStyle.CodeStyleManager
+import com.intellij.psi.impl.PsiModificationTrackerImpl
+import com.intellij.psi.util.PsiModificationTracker
 import com.intellij.util.SmartList
 import org.jetbrains.kotlin.idea.caches.resolve.getResolutionFacade
 import org.jetbrains.kotlin.idea.caches.resolve.resolveImportReference
@@ -65,6 +67,8 @@ class J2kPostProcessor(private val formatCode: Boolean) : PostProcessor {
 
             if (modificationStamp == file.modificationStamp) break
 
+            (PsiModificationTracker.SERVICE.getInstance(file.project) as? PsiModificationTrackerImpl)?.incOutOfCodeBlockModificationCounter()
+
             elementToActions = collectAvailableActions(file, rangeMarker)
         }
 

j2k/src/org/jetbrains/kotlin/j2k/CodeConverter.kt

@@ -74,9 +74,7 @@ class CodeConverter(
     }
 
     fun convertLocalVariable(variable: PsiLocalVariable): LocalVariable {
-        val isVal = variable.hasModifierProperty(PsiModifier.FINAL) ||
-                    variable.initializer == null/* we do not know actually and prefer val until we have better analysis*/ ||
-                    !variable.hasWriteAccesses(converter.referenceSearcher, variable.getContainingMethod())
+        val isVal = canChangeType(variable)
         val type = typeConverter.convertVariableType(variable)
         val explicitType = type.check { settings.specifyLocalVariableTypeByDefault || converter.shouldDeclareVariableType(variable, type, isVal) }
         return LocalVariable(variable.declarationIdentifier(),
@@ -87,6 +85,12 @@ class CodeConverter(
                              isVal).assignPrototype(variable)
     }
 
+    fun canChangeType(variable: PsiLocalVariable) : Boolean {
+        return variable.hasModifierProperty(PsiModifier.FINAL) ||
+                    variable.initializer == null/* we do not know actually and prefer val until we have better analysis*/ ||
+                    !variable.hasWriteAccesses(converter.referenceSearcher, variable.getContainingMethod())
+    }
+
     fun convertExpression(expression: PsiExpression?, expectedType: PsiType?, expectedNullability: Nullability? = null): Expression {
         if (expression == null) return Identifier.Empty
 

j2k/src/org/jetbrains/kotlin/j2k/ExpressionConverter.kt

@@ -531,7 +531,21 @@ class DefaultExpressionConverter : JavaElementVisitor(), ExpressionConverter {
 
         val referenceName = expression.referenceName!!
         val target = expression.resolve()
-        val isNullable = target is PsiVariable && typeConverter.variableNullability(target).isNullable(codeConverter.settings)
+
+        fun isNullable(target: PsiVariable): Boolean {
+            if (typeConverter.variableNullability(target).isNullable(codeConverter.settings)) return true
+
+            val canChangeType = when (target) {
+                is PsiLocalVariable -> codeConverter.canChangeType(target)
+                is PsiField -> target.hasModifierProperty(PsiModifier.PRIVATE)
+                else -> return false
+            }
+            val shouldDeclareVariableType = converter.shouldDeclareVariableType(target, converter.typeConverter.convertVariableType(target), canChangeType)
+            return !shouldDeclareVariableType && !converter.settings.specifyFieldTypeByDefault && codeConverter.convertExpression(target.initializer).isNullable
+        }
+
+        val isNullable = target is PsiVariable && isNullable(target)
+
         val qualifier = expression.qualifierExpression
 
         var identifier = Identifier(referenceName, isNullable).assignNoPrototype()

j2k/src/org/jetbrains/kotlin/j2k/ast/Expressions.kt

@@ -67,6 +67,9 @@ class TypeCastExpression(val type: Type, val expression: Expression) : Expressio
     override fun generateCode(builder: CodeBuilder) {
         builder.appendOperand(this, expression).append(" as ").append(type)
     }
+
+    override val isNullable: Boolean
+        get() = type.isNullable
 }
 
 class LiteralExpression(val literalText: String) : Expression() {

j2k/testData/fileOrElement/assertStatement/assertNotNull.kt

@@ -3,7 +3,7 @@ internal abstract class C {
         val s1 = f()!!
 
         val s2 = g() ?: error("g should not return null")
-        val h = s2!!.hashCode()
+        val h = s2.hashCode()
     }
 
     internal abstract fun f(): String?

j2k/testData/fileOrElement/nullability/notNullCast.kt

@@ -1,5 +1,3 @@
-// ERROR: Type mismatch: inferred type is Passenger.PassChild? but Passenger.PassChild was expected
-// ERROR: Type mismatch: inferred type is Passenger.PassChild? but Passenger.PassChild was expected
 class Passenger {
     open class PassParent
 
@@ -18,9 +16,9 @@ class Passenger {
         val pass = provideNullable(1)
         if (1 == 2) {
             assert(pass != null)
-            accept2(pass as PassChild?)
+            accept2((pass as PassChild?)!!)
         }
-        accept2(pass as PassChild?)
+        accept2((pass as PassChild?)!!)
     }
 
     fun accept1(p: PassChild) {

j2k/testData/fileOrElement/nullability/nullableInitializer1.java

@@ -0,0 +1,24 @@
+import org.jetbrains.annotations.Nullable;
+
+public class Test {
+    public String nullableString(int p) {
+        return p > 0 ? "response" : null;
+    }
+
+    private String nullableInitializerField = nullableString(3);
+    private String nullableInitializerFieldFinal = nullableString(3);
+    public String nullableInitializerPublicField = nullableString(3);
+
+    public void testProperty() {
+        nullableInitializerField = "aaa"
+
+        nullableInitializerField.charAt(0);
+        nullableInitializerFieldFinal.charAt(0);
+        nullableInitializerPublicField.charAt(0);
+    }
+
+    public void testLocalVariable() {
+        String nullableInitializerVal = nullableString(3);
+        nullableInitializerVal.charAt(0);
+    }
+}

j2k/testData/fileOrElement/nullability/nullableInitializer1.kt

@@ -0,0 +1,24 @@
+// ERROR: Type mismatch: inferred type is String? but String was expected
+// ERROR: Type mismatch: inferred type is String? but String was expected
+class Test {
+    fun nullableString(p: Int): String? {
+        return if (p > 0) "response" else null
+    }
+
+    private var nullableInitializerField: String = nullableString(3)
+    private val nullableInitializerFieldFinal = nullableString(3)
+    var nullableInitializerPublicField: String = nullableString(3)
+
+    fun testProperty() {
+        nullableInitializerField = "aaa"
+
+        nullableInitializerField[0]
+        nullableInitializerFieldFinal!![0]
+        nullableInitializerPublicField[0]
+    }
+
+    fun testLocalVariable() {
+        val nullableInitializerVal = nullableString(3)
+        nullableInitializerVal!![0]
+    }
+}

j2k/testData/fileOrElement/nullability/nullableInitializer2.java

@@ -0,0 +1,21 @@
+import org.jetbrains.annotations.Nullable;
+
+public class TestJava {
+    public Object nullableObj(int p) {
+        return p > 0 ? "response" : null;
+    }
+
+    public String nullableInitializerFieldCast = (String) nullableObj(3);
+    private String nullableInitializerPrivateFieldCast = (String) nullableObj(3);
+
+    public void testProperty() {
+        nullableInitializerFieldCast.charAt(0);
+        nullableInitializerPrivateFieldCast.charAt(0);
+    }
+
+    public void testLocalVariable() {
+        String nullableInitializerValCast = (String) nullableObj(3);
+
+        nullableInitializerValCast.charAt(0);
+    }
+}

j2k/testData/fileOrElement/nullability/nullableInitializer2.kt

@@ -0,0 +1,20 @@
+// ERROR: Type mismatch: inferred type is String? but String was expected
+class TestJava {
+    fun nullableObj(p: Int): Any? {
+        return if (p > 0) "response" else null
+    }
+
+    var nullableInitializerFieldCast: String = nullableObj(3) as String?
+    private val nullableInitializerPrivateFieldCast = nullableObj(3) as String?
+
+    fun testProperty() {
+        nullableInitializerFieldCast[0]
+        nullableInitializerPrivateFieldCast!![0]
+    }
+
+    fun testLocalVariable() {
+        val nullableInitializerValCast = nullableObj(3) as String?
+
+        nullableInitializerValCast!![0]
+    }
+}

j2k/testData/fileOrElement/nullability/nullableInitializer3.java

@@ -0,0 +1,20 @@
+import org.jetbrains.annotations.Nullable;
+
+public class Test {
+    public String notNullString(int p) {
+        return "response";
+    }
+
+    private String notNullInitializerField = notNullString(3);
+    public String notNullInitializerPublicField = notNullString(3);
+
+    public void testProperty() {
+        notNullInitializerField.charAt(0);
+        notNullInitializerPublicField.charAt(0);
+    }
+
+    public void testLocalVariable() {
+        String notNullInitializerVal = notNullString(3);
+        notNullInitializerVal.charAt(0);
+    }
+}

j2k/testData/fileOrElement/nullability/nullableInitializer3.kt

@@ -0,0 +1,18 @@
+class Test {
+    fun notNullString(p: Int): String {
+        return "response"
+    }
+
+    private val notNullInitializerField = notNullString(3)
+    var notNullInitializerPublicField = notNullString(3)
+
+    fun testProperty() {
+        notNullInitializerField[0]
+        notNullInitializerPublicField[0]
+    }
+
+    fun testLocalVariable() {
+        val notNullInitializerVal = notNullString(3)
+        notNullInitializerVal[0]
+    }
+}

j2k/testData/fileOrElement/nullability/nullableInitializer4.java

@@ -0,0 +1,26 @@
+import org.jetbrains.annotations.Nullable;
+
+public class TestJava {
+    private String notNullInitializerFieldNullableUsage = "aaa";
+    private String notNullInitializerFieldNotNullUsage = "aaa";
+
+    private String nullInitializerFieldNullableUsage = null;
+    private String nullInitializerFieldNotNullUsage = null;
+
+    public void testNotNull(@Nullable Object obj) {
+        if (true) {
+            notNullInitializerFieldNullableUsage = (String) obj;
+            notNullInitializerFieldNotNullUsage = "str";
+
+            notNullInitializerFieldNullableUsage.charAt(1);
+            notNullInitializerFieldNotNullUsage.charAt(1);
+        }
+        else {
+            nullInitializerFieldNullableUsage = (String) obj;
+            nullInitializerFieldNotNullUsage = "str";
+
+            nullInitializerFieldNullableUsage.charAt(1);
+            nullInitializerFieldNotNullUsage.charAt(1);
+        }
+    }
+}

j2k/testData/fileOrElement/nullability/nullableInitializer4.kt

@@ -0,0 +1,24 @@
+// ERROR: Type mismatch: inferred type is String? but String was expected
+class TestJava {
+    private var notNullInitializerFieldNullableUsage = "aaa"
+    private var notNullInitializerFieldNotNullUsage = "aaa"
+
+    private var nullInitializerFieldNullableUsage: String? = null
+    private var nullInitializerFieldNotNullUsage: String? = null
+
+    fun testNotNull(obj: Any?) {
+        if (true) {
+            notNullInitializerFieldNullableUsage = obj as String?
+            notNullInitializerFieldNotNullUsage = "str"
+
+            notNullInitializerFieldNullableUsage[1]
+            notNullInitializerFieldNotNullUsage[1]
+        } else {
+            nullInitializerFieldNullableUsage = obj as String?
+            nullInitializerFieldNotNullUsage = "str"
+
+            nullInitializerFieldNullableUsage!![1]
+            nullInitializerFieldNotNullUsage!![1]
+        }
+    }
+}

j2k/tests/org/jetbrains/kotlin/j2k/JavaToKotlinConverterForWebDemoTestGenerated.java

@@ -3517,6 +3517,30 @@ public class JavaToKotlinConverterForWebDemoTestGenerated extends AbstractJavaTo
             doTest(fileName);
         }
 
+        @TestMetadata("nullableInitializer1.java")
+        public void testNullableInitializer1() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("j2k/testData/fileOrElement/nullability/nullableInitializer1.java");
+            doTest(fileName);
+        }
+
+        @TestMetadata("nullableInitializer2.java")
+        public void testNullableInitializer2() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("j2k/testData/fileOrElement/nullability/nullableInitializer2.java");
+            doTest(fileName);
+        }
+
+        @TestMetadata("nullableInitializer3.java")
+        public void testNullableInitializer3() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("j2k/testData/fileOrElement/nullability/nullableInitializer3.java");
+            doTest(fileName);
+        }
+
+        @TestMetadata("nullableInitializer4.java")
+        public void testNullableInitializer4() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("j2k/testData/fileOrElement/nullability/nullableInitializer4.java");
+            doTest(fileName);
+        }
+
         @TestMetadata("NullableIntNoCrash.java")
         public void testNullableIntNoCrash() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("j2k/testData/fileOrElement/nullability/NullableIntNoCrash.java");

j2k/tests/org/jetbrains/kotlin/j2k/JavaToKotlinConverterSingleFileTestGenerated.java

@@ -3517,6 +3517,30 @@ public class JavaToKotlinConverterSingleFileTestGenerated extends AbstractJavaTo
             doTest(fileName);
         }
 
+        @TestMetadata("nullableInitializer1.java")
+        public void testNullableInitializer1() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("j2k/testData/fileOrElement/nullability/nullableInitializer1.java");
+            doTest(fileName);
+        }
+
+        @TestMetadata("nullableInitializer2.java")
+        public void testNullableInitializer2() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("j2k/testData/fileOrElement/nullability/nullableInitializer2.java");
+            doTest(fileName);
+        }
+
+        @TestMetadata("nullableInitializer3.java")
+        public void testNullableInitializer3() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("j2k/testData/fileOrElement/nullability/nullableInitializer3.java");
+            doTest(fileName);
+        }
+
+        @TestMetadata("nullableInitializer4.java")
+        public void testNullableInitializer4() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("j2k/testData/fileOrElement/nullability/nullableInitializer4.java");
+            doTest(fileName);
+        }
+
         @TestMetadata("NullableIntNoCrash.java")
         public void testNullableIntNoCrash() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("j2k/testData/fileOrElement/nullability/NullableIntNoCrash.java");