Fix ternary operator with null assigned to listener.

Bug 22907244

When finding a common type, null is an Object and
the listener is an interface, so the types don't
match.

Change-Id: I0c5a88ec02230767b894b2feda17a1a1c8cef9f7

2 files changed, 19 insertions, 0 deletions

diff --git a/compiler/src/main/java/android/databinding/tool/expr/TernaryExpr.java b/compiler/src/main/java/android/databinding/tool/expr/TernaryExpr.java
index f8f61123..a1a4432a 100644
--- a/compiler/src/main/java/android/databinding/tool/expr/TernaryExpr.java
+++ b/compiler/src/main/java/android/databinding/tool/expr/TernaryExpr.java
@@ -48,10 +48,23 @@ public class TernaryExpr extends Expr {
 
     @Override
     protected ModelClass resolveType(ModelAnalyzer modelAnalyzer) {
+        final Expr ifTrue = getIfTrue();
+        final Expr ifFalse = getIfFalse();
+        if (isNullLiteral(ifTrue)) {
+            return ifFalse.getResolvedType();
+        } else if (isNullLiteral(ifFalse)) {
+            return ifTrue.getResolvedType();
+        }
         return modelAnalyzer.findCommonParentOf(getIfTrue().getResolvedType(),
                 getIfFalse().getResolvedType());
     }
 
+    private static boolean isNullLiteral(Expr expr) {
+        final ModelClass type = expr.getResolvedType();
+        return (type.isObject() && (expr instanceof SymbolExpr) &&
+                "null".equals(((SymbolExpr)expr).getText()));
+    }
+
     @Override
     protected List<Dependency> constructDependencies() {
         List<Dependency> deps = new ArrayList<>();
diff --git a/compiler/src/main/java/android/databinding/tool/reflection/ModelAnalyzer.java b/compiler/src/main/java/android/databinding/tool/reflection/ModelAnalyzer.java
index 739c9e0b..b1de46e4 100644
--- a/compiler/src/main/java/android/databinding/tool/reflection/ModelAnalyzer.java
+++ b/compiler/src/main/java/android/databinding/tool/reflection/ModelAnalyzer.java
@@ -94,6 +94,12 @@ public abstract class ModelAnalyzer {
             curr = curr.getSuperclass();
         }
         if (curr == null) {
+            if (modelClass1.isObject() && modelClass2.isInterface()) {
+                return modelClass1;
+            } else if (modelClass2.isObject() && modelClass1.isInterface()) {
+                return modelClass2;
+            }
+
             ModelClass primitive1 = modelClass1.unbox();
             ModelClass primitive2 = modelClass2.unbox();
             if (!modelClass1.equals(primitive1) || !modelClass2.equals(primitive2)) {