android: fix missing Hilt GeneratedInjector in asm transform

android/CHANGELOG.md

@@ -983,3 +983,14 @@
 - Upgraded attachment audio player behavior (voice + audio):
   - added seek slider for manual rewind/fast-forward,
   - unified speed toggle for both `voice` and `audio` playback.
+
+### Step 134 - Hilt startup crash fix (`MessengerApplication_GeneratedInjector`)
+- Fixed startup crash:
+  - `NoClassDefFoundError: MessengerApplication_GeneratedInjector`.
+- Root cause observed in build pipeline:
+  - `MessengerApplication_GeneratedInjector.class` existed after `javac`,
+  - but was missing in `transformDebugClassesWithAsm/dirs` before dexing.
+- Added Gradle backfill task for `debug/release` variants:
+  - copies `*Application_GeneratedInjector.class` from `intermediates/javac/.../classes`
+    into `intermediates/classes/.../transform...ClassesWithAsm/dirs` if missing,
+  - wired task as dependency of `dexBuilder<Variant>`.

android/app/build.gradle.kts

@@ -127,3 +127,37 @@ dependencies {
 kapt {
     correctErrorTypes = true
 }
+
+fun registerHiltInjectorBackfillTask(variantName: String) {
+    val cap = variantName.replaceFirstChar { if (it.isLowerCase()) it.titlecase() else it.toString() }
+    val taskName = "backfill${cap}HiltApplicationInjector"
+    val dexBuilderTaskName = "dexBuilder$cap"
+    val compileJavaTaskName = "compile${cap}JavaWithJavac"
+
+    tasks.register(taskName) {
+        dependsOn(compileJavaTaskName)
+        doLast {
+            val javacOutput = file("$buildDir/intermediates/javac/$variantName/$compileJavaTaskName/classes")
+            val asmOutput = file("$buildDir/intermediates/classes/$variantName/transform${cap}ClassesWithAsm/dirs")
+            if (!javacOutput.exists() || !asmOutput.exists()) return@doLast
+
+            fileTree(javacOutput) {
+                include("**/*Application_GeneratedInjector.class")
+            }.forEach { source ->
+                val relativePath = source.relativeTo(javacOutput).path
+                val target = file("${asmOutput.path}/$relativePath")
+                if (!target.exists()) {
+                    target.parentFile?.mkdirs()
+                    source.copyTo(target, overwrite = true)
+                }
+            }
+        }
+    }
+
+    tasks.matching { it.name == dexBuilderTaskName }.configureEach {
+        dependsOn(taskName)
+    }
+}
+
+registerHiltInjectorBackfillTask("debug")
+registerHiltInjectorBackfillTask("release")