A better way to provide backward compatibility with old color schemes

platform/core-api/src/com/intellij/openapi/editor/markup/TextAttributes.java

@@ -32,6 +32,8 @@ public class TextAttributes implements JDOMExternalizable, Cloneable {
 
   public static final TextAttributes ERASE_MARKER = new TextAttributes();
 
+  private boolean myEnforcedDefaults = false;
+
   /**
    * Merges (layers) the two given text attributes.
    *
@@ -175,6 +177,10 @@ public class TextAttributes implements JDOMExternalizable, Cloneable {
     return getForegroundColor() == null && getBackgroundColor() == null && getEffectColor() == null && getFontType() == Font.PLAIN;
   }
 
+  public boolean isFallbackEnabled() {
+    return isEmpty() && !myEnforcedDefaults;
+  }
+
   public void reset() {
     setForegroundColor(null);
     setBackgroundColor(null);
@@ -251,6 +257,7 @@ public class TextAttributes implements JDOMExternalizable, Cloneable {
   public TextAttributes clone() {
     TextAttributes cloned = new TextAttributes();
     cloned.myAttrs = myAttrs;
+    cloned.myEnforcedDefaults = myEnforcedDefaults;
     return cloned;
   }
 
@@ -276,6 +283,7 @@ public class TextAttributes implements JDOMExternalizable, Cloneable {
                                          ext.EFFECT_COLOR,
                                          ext.getEffectType(),
                                          ext.ERROR_STRIPE_COLOR);
+    if (isEmpty()) myEnforcedDefaults = true;
   }
 
   @Override

platform/lang-api/src/com/intellij/openapi/editor/DefaultLanguageHighlighterColors.java

@@ -28,7 +28,7 @@ public class DefaultLanguageHighlighterColors {
   public final static TextAttributesKey TEMPLATE_LANGUAGE_COLOR =
     TextAttributesKey.createTextAttributesKey("DEFAULT_TEMPLATE_LANGUAGE_COLOR", HighlighterColors.TEXT);
   public final static TextAttributesKey IDENTIFIER =
-    TextAttributesKey.createTextAttributesKey("DEFAULT_IDENTIFIER");
+    TextAttributesKey.createTextAttributesKey("DEFAULT_IDENTIFIER", HighlighterColors.TEXT);
   public final static TextAttributesKey NUMBER =
     TextAttributesKey.createTextAttributesKey("DEFAULT_NUMBER");
   public final static TextAttributesKey KEYWORD =

platform/lang-impl/src/com/intellij/application/options/colors/ColorAndFontOptions.java

@@ -815,7 +815,7 @@ public class ColorAndFontOptions extends SearchableConfigurable.Parent.Abstract
 
     @Override
     public boolean isInherited() {
-      return myFallbackAttributes != null && getTextAttributes().isEmpty();
+      return myFallbackAttributes != null && getTextAttributes().isFallbackEnabled();
     }
 
     @Nullable

platform/platform-impl/src/com/intellij/openapi/editor/colors/impl/AbstractColorsScheme.java

@@ -442,7 +442,7 @@ public abstract class AbstractColorsScheme implements EditorColorsScheme {
   }
 
   private boolean haveToWrite(final TextAttributesKey key, final TextAttributes value, final TextAttributes defaultAttribute) {
-    if (key.getFallbackAttributeKey() != null && value.isEmpty()) return false;
+    if (key.getFallbackAttributeKey() != null && value.isFallbackEnabled()) return false;
     boolean hasDefaultValue = value.equals(defaultAttribute);
     if (myParentScheme == null) return !hasDefaultValue;
     return true;
@@ -559,7 +559,7 @@ public abstract class AbstractColorsScheme implements EditorColorsScheme {
     if (fallbackKey == null) return null;
     if (myAttributesMap.containsKey(fallbackKey)) {
       TextAttributes fallbackAttributes = myAttributesMap.get(fallbackKey);
-      if (fallbackAttributes != null && (!fallbackAttributes.isEmpty() || fallbackKey.getFallbackAttributeKey() == null)) {
+      if (fallbackAttributes != null && (!fallbackAttributes.isFallbackEnabled() || fallbackKey.getFallbackAttributeKey() == null)) {
         return fallbackAttributes;
       }
     }

platform/platform-impl/src/com/intellij/openapi/editor/colors/impl/EditorColorsSchemeImpl.java

@@ -60,12 +60,9 @@ public class EditorColorsSchemeImpl extends AbstractColorsScheme implements Exte
         if (attributes != null) return attributes;
       }
       else {
-        if (attributes != null && !attributes.isEmpty()) return attributes;
+        if (attributes != null && !attributes.isFallbackEnabled()) return attributes;
         attributes = getFallbackAttributes(fallbackKey);
         if (attributes != null) return attributes;
-        if (myParentScheme instanceof DefaultColorsScheme && !DEFAULT_SCHEME_NAME.equals(getName())) {
-          return null;
-        }
       }
     }
     return myParentScheme.getAttributes(key);