Detect common null check ternary ops

This CL adds logic to the Ternary expression to avoid unboxing
if the predicate is a null check.

e.g. if it is a == null ? b : a, we don't need to unbox  for the
false statement because it will not be executed if a is null.

This is not a complete nullability detection code, it only covers the
common cases.

Bug: 37127560
Test: SafeUnboxingTest
Change-Id: I7a090b7dc92f1c127cc3b63f7eab3f6c37a250a8

1 files changed, 1 insertions, 1 deletions

diff --git a/compiler/src/main/kotlin/android/databinding/tool/writer/LayoutBinderWriter.kt b/compiler/src/main/kotlin/android/databinding/tool/writer/LayoutBinderWriter.kt
index 52cf109f..6659cd53 100644
--- a/compiler/src/main/kotlin/android/databinding/tool/writer/LayoutBinderWriter.kt
+++ b/compiler/src/main/kotlin/android/databinding/tool/writer/LayoutBinderWriter.kt
@@ -1156,7 +1156,7 @@ class LayoutBinderWriter(val layoutBinder : LayoutBinder) {
                 it.isMandatory && it.other.resolvedType.isNullable
             }.map { it.other }
             if (!expr.isEqualityCheck && nullables.isNotEmpty()) {
-                return "${nullables.map { "${it.executePendingLocalName} != null" }.joinToString(" && ")}"
+                return nullables.map { "${it.executePendingLocalName} != null" }.joinToString(" && ")
             } else {
                 return null
             }