Javafx: Resolve $null symbol and ${null} expression in FXML (IDEA-112153)

plugins/javaFX/javaFX-CE/testSrc/org/jetbrains/plugins/javaFX/fxml/JavaFXHighlightingTest.java

@@ -374,6 +374,14 @@ public class JavaFXHighlightingTest extends AbstractJavaFXTestCase {
     doTest();
   }
 
+  public void testNullObjectValue() throws Exception {
+    doTest();
+  }
+
+  public void testNullPrimitiveValue() throws Exception {
+    doTest();
+  }
+
   public void testFactoryMethod() throws Exception {
     doTest();
   }

plugins/javaFX/src/org/jetbrains/plugins/javaFX/fxml/FxmlConstants.java

@@ -15,8 +15,10 @@
  */
 package org.jetbrains.plugins.javaFX.fxml;
 
+import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.NonNls;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.*;
 
@@ -51,6 +53,9 @@ public class FxmlConstants {
 
   @NonNls public static final String SOURCE = "source";
 
+  @NonNls public static final String NULL_EXPRESSION = "${null}";
+  @NonNls private static final String NULL_VALUE = "$null";
+
   public static final Set<String> FX_BUILT_IN_ATTRIBUTES =
     ContainerUtil.immutableSet(FX_ID, FX_CONTROLLER, VALUE, FX_VALUE, FX_FACTORY, FX_CONSTANT);
 
@@ -71,4 +76,7 @@ public class FxmlConstants {
       .put(FX_COPY, Collections.singletonList(SOURCE))
       .build();
 
+  public static boolean isNullValue(@NotNull String value) {
+    return NULL_VALUE.equals(StringUtil.trimTrailing(value));
+  }
 }

plugins/javaFX/src/org/jetbrains/plugins/javaFX/fxml/JavaFxPsiUtil.java

@@ -38,6 +38,7 @@ import com.intellij.xml.XmlAttributeDescriptor;
 import com.intellij.xml.XmlElementDescriptor;
 import gnu.trove.THashMap;
 import gnu.trove.THashSet;
+import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -804,11 +805,19 @@ public class JavaFxPsiUtil {
 
   @Nullable
   public static PsiClass getWritablePropertyClass(@Nullable XmlAttributeValue xmlAttributeValue) {
+    if (xmlAttributeValue != null) {
+      return getPropertyClass(getWritablePropertyType(xmlAttributeValue), xmlAttributeValue);
+    }
+    return null;
+  }
+
+  @Nullable
+  public static PsiType getWritablePropertyType(@Nullable XmlAttributeValue xmlAttributeValue) {
     final PsiClass tagClass = getTagClass(xmlAttributeValue);
     if (tagClass != null) {
       final PsiElement declaration = getAttributeDeclaration(xmlAttributeValue);
       if (declaration != null) {
-        return getPropertyClass(getWritablePropertyType(tagClass, declaration), xmlAttributeValue);
+        return getWritablePropertyType(tagClass, declaration);
       }
     }
     return null;
@@ -843,6 +852,7 @@ public class JavaFxPsiUtil {
     return null;
   }
 
+  @Contract("null->false")
   public static boolean isPrimitiveOrBoxed(@Nullable PsiType psiType) {
     return psiType instanceof PsiPrimitiveType || PsiPrimitiveType.getUnboxedType(psiType) != null;
   }

plugins/javaFX/src/org/jetbrains/plugins/javaFX/fxml/descriptors/JavaFxPropertyAttributeDescriptor.java

@@ -9,6 +9,7 @@ import com.intellij.util.ArrayUtil;
 import com.intellij.xml.impl.BasicXmlAttributeDescriptor;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jetbrains.plugins.javaFX.fxml.FxmlConstants;
 import org.jetbrains.plugins.javaFX.fxml.JavaFxCommonNames;
 import org.jetbrains.plugins.javaFX.fxml.JavaFxPsiUtil;
 
@@ -129,6 +130,9 @@ public class JavaFxPropertyAttributeDescriptor extends BasicXmlAttributeDescript
     if (value.startsWith("$")) {
       return validatePropertyExpression(xmlAttributeValue, value);
     }
+    else if (StringUtil.trimLeading(value).startsWith("$")) {
+      return "Spaces aren't allowed before property or expression";
+    }
     else {
       return validateLiteral(xmlAttributeValue, value);
     }
@@ -160,9 +164,17 @@ public class JavaFxPropertyAttributeDescriptor extends BasicXmlAttributeDescript
     if (isIncompletePropertyChain(propertyNames)) {
       return "Incorrect expression syntax";
     }
+    if (FxmlConstants.NULL_EXPRESSION.equals(value)) return null;
 
     final XmlTag currentTag = PsiTreeUtil.getParentOfType(xmlAttributeValue, XmlTag.class);
-    final PsiClass targetPropertyClass = JavaFxPsiUtil.getWritablePropertyClass(xmlAttributeValue);
+    final PsiType targetPropertyType = JavaFxPsiUtil.getWritablePropertyType(xmlAttributeValue);
+    if (FxmlConstants.isNullValue(value)) {
+      if (JavaFxPsiUtil.isPrimitiveOrBoxed(targetPropertyType)) {
+        return "Unable to coerce to " + targetPropertyType.getPresentableText();
+      }
+      return null;
+    }
+    final PsiClass targetPropertyClass = JavaFxPsiUtil.getPropertyClass(targetPropertyType, xmlAttributeValue);
     if (targetPropertyClass == null || JavaFxPsiUtil.hasConversionFromAnyType(targetPropertyClass)) return null;
 
     final String firstPropertyName = propertyNames.get(0);
@@ -242,7 +254,7 @@ public class JavaFxPropertyAttributeDescriptor extends BasicXmlAttributeDescript
 
   @Override
   public PsiReference[] getValueReferences(XmlElement element, @NotNull String text) {
-    return !text.startsWith("${") ? super.getValueReferences(element, text) : PsiReference.EMPTY_ARRAY;
+    return !text.startsWith("${") && !FxmlConstants.isNullValue(text) ? super.getValueReferences(element, text) : PsiReference.EMPTY_ARRAY;
   }
 
   @Override

plugins/javaFX/src/org/jetbrains/plugins/javaFX/fxml/refs/JavaFxComponentIdReferenceProvider.java

@@ -81,6 +81,7 @@ public class JavaFxComponentIdReferenceProvider extends PsiReferenceProvider {
                                                         @NotNull XmlAttributeValue xmlAttributeValue,
                                                         @NotNull String value,
                                                         @NotNull Map<String, XmlAttributeValue> fileIds) {
+    if (FxmlConstants.NULL_EXPRESSION.equals(value)) return PsiReference.EMPTY_ARRAY;
     final String expressionBody = value.substring(2, value.length() - 1);
     final List<String> propertyNames = StringUtil.split(expressionBody, ".", true, false);
     if (JavaFxPropertyAttributeDescriptor.isIncompletePropertyChain(propertyNames)) return PsiReference.EMPTY_ARRAY;
@@ -115,6 +116,7 @@ public class JavaFxComponentIdReferenceProvider extends PsiReferenceProvider {
   private static PsiReference[] getSinglePropertyReferences(@NotNull XmlAttributeValue xmlAttributeValue,
                                                             @NotNull String value,
                                                             @NotNull Map<String, XmlAttributeValue> fileIds) {
+    if (FxmlConstants.isNullValue(value)) return PsiReference.EMPTY_ARRAY;
     return getSinglePropertyReferences(xmlAttributeValue, fileIds, value.substring(1), 1);
   }
 

plugins/javaFX/testData/highlighting/nullObjectValue.fxml

@@ -0,0 +1,9 @@
+<?import javafx.scene.control.Button?>
+<?import javafx.scene.layout.VBox?>
+<?import javafx.scene.control.Label?>
+<VBox xmlns="http://javafx.com/javafx/8.0.91">
+  <Label text="${null}" textAlignment="$null "/>
+  <Button text="$null " tooltip="$null" textAlignment="${null}"/>
+  <Label text=<error descr="Spaces aren't allowed before property or expression">" ${null}"</error>/>
+  <Label text=<error descr="Spaces aren't allowed before property or expression">" $null"</error>/>
+</VBox>

plugins/javaFX/testData/highlighting/nullPrimitiveValue.fxml

@@ -0,0 +1,8 @@
+<?import javafx.scene.control.Button?>
+<?import javafx.scene.layout.VBox?>
+<?import javafx.scene.control.Label?>
+<VBox xmlns="http://javafx.com/javafx/8.0.91">
+  <Button text="Button1" prefWidth=<error descr="Unable to coerce to double">"$null"</error>/>
+  <Button text="Button2" prefWidth="${null}"/>
+  <Button text="Button3"  defaultButton=<error descr="Unable to coerce to boolean">"$null"</error>/>
+</VBox>