Read library glide module names from Java indexes

Progress for bumptech#5043

Annotation processors (including ksp) only run on newly compiled code.
Libraries have been previously compiled, so an annotation processor will
not be run on them. To find any LibraryGlideModules included in those
libraries, we look for specific generated classes in those libraries
that we call Indexes. Indexes contain an annotation listing the class
names of any LibraryGlideModules. Indexes are generated by Glide's
annotation processors for each library and are exported as part of the
library.

To preserve the package private visibility of the existing Java Index
annotation, I created a new Index annotation for the KSP processor. This
lets us reference the KSP Index annotation directly.

Unfortunately it also means that the Java and KSP Index classes are not
the same. While it's only a small amount of duplicated code, it's a
significant compatibility issue because the KSP and Java processors no
longer produce the same Index class.

In particular the KSP processor looks only for its Index class and not
for the Java processor's Index class. This is unfortunate because
Glide's libraries are always processed by the Java annotation processor,
not the KSP processor. In turn this means that Glide's KSP processor
effectively ignores any of Glide's integration libraries.

To fix this in the short term I've made the KSP processor look for both
its Indexes and the Java annotation processors Indexes. A more robust
fix would be to merge the two Index processors so that the annotation
processors are mutually compatible. I'll do that in a follow-up.

Unfortunately this is difficult to test. We can (and already have)
verifified across compilations that the KSP processor can correctly
read its own Indexes. However the android and Java plugins in gradle
seem to be incompatible so I can't find a way to use
kotlin-compile-testing to compile the library using the Java processor
and then run the KSP processor on the result. I'll keep looking, but
I'm not super optimistic.

annotation/ksp/src/main/kotlin/com/bumptech/glide/annotation/ksp/AppGlideModules.kt

@@ -191,23 +191,57 @@ internal class AppGlideModuleParser(
   private fun getIndexesAndLibraryGlideModuleNames(): IndexFilesAndLibraryModuleNames {
     val allIndexFiles: MutableList<KSDeclaration> = mutableListOf()
     val allLibraryGlideModuleNames: MutableList<String> = mutableListOf()
-    resolver.getDeclarationsFromPackage(GlideSymbolProcessorConstants.PACKAGE_NAME).forEach {
-      index: KSDeclaration ->
-      val libraryGlideModuleNames = extractGlideModulesFromIndexAnnotation(index)
-      if (libraryGlideModuleNames.isNotEmpty()) {
-        allIndexFiles.add(index)
-        allLibraryGlideModuleNames.addAll(libraryGlideModuleNames)
-      }
+
+    val allIndexesAndLibraryModules =
+      getAllLibraryNamesFromJavaIndexes() + getAllLibraryNamesFromKspIndexes()
+    for ((index, libraryGlideModuleNames) in allIndexesAndLibraryModules) {
+      allIndexFiles.add(index)
+      allLibraryGlideModuleNames.addAll(libraryGlideModuleNames)
     }
 
     return IndexFilesAndLibraryModuleNames(allIndexFiles, allLibraryGlideModuleNames)
   }
 
-  private fun extractGlideModulesFromIndexAnnotation(
+  internal data class IndexAndLibraryModuleNames(
+    val index: KSDeclaration, val libraryModuleNames: List<String>
+  )
+
+  private fun getAllLibraryNamesFromKspIndexes(): List<IndexAndLibraryModuleNames> =
+    getAllLibraryNamesFromIndexes(GlideSymbolProcessorConstants.PACKAGE_NAME) { index ->
+      extractGlideModulesFromKspIndexAnnotation(index)
+    }
+
+  private fun getAllLibraryNamesFromJavaIndexes(): List<IndexAndLibraryModuleNames> =
+    getAllLibraryNamesFromIndexes(GlideSymbolProcessorConstants.JAVA_ANNOTATION_PACKAGE_NAME) {
+        index -> extractGlideModulesFromJavaIndexAnnotation(index)
+    }
+
+  @OptIn(KspExperimental::class)
+  private fun getAllLibraryNamesFromIndexes(
+    packageName: String, extractLibraryModuleNamesFromIndex: (KSDeclaration) -> List<String>
+  ) = buildList {
+    resolver.getDeclarationsFromPackage(packageName)
+      .forEach { index: KSDeclaration ->
+        val libraryGlideModuleNames = extractLibraryModuleNamesFromIndex(index)
+        if (libraryGlideModuleNames.isNotEmpty()) {
+          add(IndexAndLibraryModuleNames(index, libraryGlideModuleNames))
+        }
+      }
+  }
+
+  private fun extractGlideModulesFromJavaIndexAnnotation(
+    index: KSDeclaration,
+  ): List<String> {
+    val indexAnnotation: KSAnnotation = index.atMostOneJavaIndexAnnotation() ?: return emptyList()
+    environment.logger.info("Found java index annotation: $indexAnnotation")
+    return indexAnnotation.getModuleArgumentValues().toList()
+  }
+
+  private fun extractGlideModulesFromKspIndexAnnotation(
     index: KSDeclaration,
   ): List<String> {
-    val indexAnnotation: KSAnnotation = index.atMostOneIndexAnnotation() ?: return emptyList()
-    environment.logger.info("Found index annotation: $indexAnnotation")
+    val indexAnnotation: KSAnnotation = index.atMostOneKspIndexAnnotation() ?: return emptyList()
+    environment.logger.info("Found ksp index annotation: $indexAnnotation")
     return indexAnnotation.getModuleArgumentValues().toList()
   }
 
@@ -220,29 +254,36 @@ internal class AppGlideModuleParser(
     throw InvalidGlideSourceException("Found an invalid internal Glide index: $this")
   }
 
-  private fun KSDeclaration.atMostOneIndexAnnotation() = atMostOneAnnotation(Index::class)
+  private fun KSDeclaration.atMostOneJavaIndexAnnotation() =
+    atMostOneAnnotation("com.bumptech.glide.annotation.compiler.Index")
+  private fun KSDeclaration.atMostOneKspIndexAnnotation() = atMostOneAnnotation(Index::class)
 
   private fun KSDeclaration.atMostOneExcludesAnnotation() = atMostOneAnnotation(Excludes::class)
 
   private fun KSDeclaration.atMostOneAnnotation(
     annotation: KClass<out Annotation>,
+  ): KSAnnotation? = atMostOneAnnotation(annotation.qualifiedName)
+
+  private fun KSDeclaration.atMostOneAnnotation(
+    annotationQualifiedName: String?,
   ): KSAnnotation? {
     val matchingAnnotations: List<KSAnnotation> =
       annotations
         .filter {
-          annotation.qualifiedName?.equals(
+          annotationQualifiedName?.equals(
             it.annotationType.resolve().declaration.qualifiedName?.asString()
           )
             ?: false
         }
         .toList()
     if (matchingAnnotations.size > 1) {
       throw InvalidGlideSourceException(
-        """Expected 0 or 1 $annotation annotations on $qualifiedName, but found: 
+        """Expected 0 or 1 $annotationQualifiedName annotations on $qualifiedName, but found: 
           ${matchingAnnotations.size}"""
       )
     }
     return matchingAnnotations.singleOrNull()
+
   }
 }
 

annotation/ksp/src/main/kotlin/com/bumptech/glide/annotation/ksp/GlideSymbolProcessor.kt

@@ -144,6 +144,7 @@ object GlideSymbolProcessorConstants {
   // This variable is visible only for testing
   // TODO(b/174783094): Add @VisibleForTesting when internal is supported.
   val PACKAGE_NAME: String = GlideSymbolProcessor::class.java.`package`.name
+  val JAVA_ANNOTATION_PACKAGE_NAME: String = "com.bumptech.glide.annotation.compiler"
   const val SINGLE_APP_MODULE_ERROR = "You can have at most one AppGlideModule, but found: %s"
   const val DUPLICATE_LIBRARY_MODULE_ERROR =
     "LibraryGlideModules %s are included more than once, keeping only one!"