1 files changed, 2 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidRuleClasses.java b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidRuleClasses.java
index d4ca2ad1c2..18f0b5b622 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidRuleClasses.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidRuleClasses.java
@@ -297,6 +297,8 @@ public final class AndroidRuleClasses {
       return builder
           .requiresConfigurationFragments(JavaConfiguration.class, AndroidConfiguration.class)
           .setUndocumented()
+          // build_tools_version is assumed to be the latest version if omitted.
+          .add(attr("build_tools_version", STRING))
           // This is the Proguard that comes from the --proguard_top attribute.
           .add(attr(":proguard", LABEL).cfg(HOST).value(JavaSemantics.PROGUARD).exec())
           // This is the Proguard in the BUILD file that contains the android_sdk rule. Used when