Another fix for missing rootComponentNames from older version of Dagger.

Fixes #4898.

RELNOTES=n/a
PiperOrigin-RevId: 802766550

Author: Chang-Eric

hilt-compiler/main/java/dagger/hilt/processor/internal/root/AggregatedRootMetadata.java

@@ -97,14 +97,24 @@ private static AggregatedRootMetadata create(XTypeElement element, XProcessingEn
         rootElement,
         env.requireTypeElement(annotation.getAsString("originatingRoot")),
         annotation.getAsType("rootAnnotation").getTypeElement(),
-        parseClassName(
+        parseRootComponentClassName(
             annotation.getAsString("rootComponentPackage"),
             annotation.getAsStringList("rootComponentSimpleNames")),
         allowSharingComponent);
   }
 
-  private static ClassName parseClassName(String pkg, List<String> simpleNames) {
+  private static ClassName parseRootComponentClassName(
+      String rootComponentPackage, List<String> rootComponentSimpleNames) {
+    // If rootComponentPackage isn't there, that means that this is likely coming from an older
+    // Dagger version, so assume the root component is the SingletonComponent for backwards
+    // compatibility.
+    if (rootComponentPackage.isEmpty()) {
+      return ClassNames.SINGLETON_COMPONENT;
+    }
     return ClassName.get(
-        pkg, simpleNames.get(0), simpleNames.subList(1, simpleNames.size()).toArray(new String[0]));
+        rootComponentPackage,
+        rootComponentSimpleNames.get(0),
+        rootComponentSimpleNames.subList(1, rootComponentSimpleNames.size())
+            .toArray(new String[0]));
   }
 }

java/dagger/hilt/android/plugin/main/src/main/kotlin/dagger/hilt/android/plugin/root/Aggregator.kt

@@ -167,19 +167,14 @@ private constructor(private val logger: Logger, private val asmApiVersion: Int)
                   originatingRootClass,
                 )
               val rootComponentName =
-                // TODO(erichang): This is a bit of a hedge since the rootComponentPackage attribute
-                // has a default value. So either the visitor visits it even if unset because it has
-                // a default and it is always initialized and we only need the empty check or it
-                // doesn't visit it despite the default value and we only need the initialized
-                // check. The ASM documentation wasn't very clear though and since this cross
-                // version setup is a bit difficult to test, just checking both for now to get this
-                // fixed quickly.
-                if (::rootComponentPackage.isInitialized && !rootComponentPackage.isEmpty()) {
+                // If rootComponentPackage isn't there, that means that this is likely coming from
+                // an older Dagger version, so assume the root component is the SingletonComponent
+                // for backwards compatibility.
+                // Also, even though these have default values, if they are unset then the visitor
+                // still does not visit them so we only have to check if it is initialized.
+                if (::rootComponentPackage.isInitialized) {
                   parseClassName(rootComponentPackage, rootComponentSimpleNames)
                 } else {
-                  // If rootComponentPackage isn't there, that means that this is likely coming from
-                  // an older Dagger version, so assume the root component is the SingletonComponent
-                  // for backwards compatibility.
                   SINGLETON_COMPONENT
                 }