Add better logging for ovesized messages.

core/util-jvm/src/main/java/org/signal/core/util/ProtoExtensions.kt

@@ -12,8 +12,10 @@ import com.squareup.wire.Message
 import com.squareup.wire.ProtoAdapter
 import com.squareup.wire.ProtoReader
 import com.squareup.wire.ProtoWriter
+import com.squareup.wire.WireField
 import okio.Buffer
 import okio.ByteString
+import okio.utf8Size
 import org.signal.core.util.logging.Log
 import java.io.IOException
 import java.util.LinkedList
@@ -87,6 +89,96 @@ fun writeUnknownEnumValue(tag: Int, enumValue: Int): ByteString {
   return buffer.readByteString()
 }
 
+/**
+ * Builds a human-readable tree of serialized sizes for this proto message,
+ * recursively descending into all nested message fields. Useful for debugging
+ * oversized messages.
+ *
+ * Example output:
+ * ```
+ * Content(1234)
+ *   dataMessage(1100)
+ *     body(500)
+ *     groupV2(400)
+ *       groupChange(350)
+ *     attachments[2](200)
+ * ```
+ */
+fun Message<*, *>.buildSizeTree(name: String): String {
+  val sb = StringBuilder()
+  appendSizeTree(name, 0, sb)
+  return sb.toString()
+}
+
+@Suppress("UNCHECKED_CAST")
+private fun Message<*, *>.appendSizeTree(name: String, depth: Int, sb: StringBuilder) {
+  val totalSize = (adapter as ProtoAdapter<Message<*, *>>).encodedSize(this)
+  repeat(depth) { sb.append("  ") }
+  sb.append(name).append("(").append(totalSize).append(")")
+
+  for (field in this.javaClass.declaredFields) {
+    field.getAnnotation(WireField::class.java) ?: continue
+
+    val value = try {
+      field.get(this)
+    } catch (_: IllegalAccessException) {
+      continue
+    } ?: continue
+
+    val fieldName = field.name
+
+    when (value) {
+      is Message<*, *> -> {
+        sb.append("\n")
+        value.appendSizeTree(fieldName, depth + 1, sb)
+      }
+      is List<*> -> {
+        if (value.isNotEmpty()) {
+          var listTotalSize = 0
+          val isMessageList = value[0] is Message<*, *>
+          for (item in value) {
+            when (item) {
+              is Message<*, *> -> listTotalSize += (item.adapter as ProtoAdapter<Message<*, *>>).encodedSize(item)
+              is ByteString -> listTotalSize += item.size
+              is String -> listTotalSize += item.utf8Size().toInt()
+            }
+          }
+          sb.append("\n")
+          repeat(depth + 1) { sb.append("  ") }
+          sb.append(fieldName).append("[").append(value.size).append("](").append(listTotalSize).append(")")
+
+          if (isMessageList) {
+            for (i in value.indices) {
+              sb.append("\n")
+              (value[i] as Message<*, *>).appendSizeTree("${fieldName}[$i]", depth + 2, sb)
+            }
+          }
+        }
+      }
+      is ByteString -> {
+        if (value.size > 0) {
+          sb.append("\n")
+          repeat(depth + 1) { sb.append("  ") }
+          sb.append(fieldName).append("(").append(value.size).append(")")
+        }
+      }
+      is String -> {
+        if (value.isNotEmpty()) {
+          sb.append("\n")
+          repeat(depth + 1) { sb.append("  ") }
+          sb.append(fieldName).append("(").append(value.utf8Size().toInt()).append(")")
+        }
+      }
+    }
+  }
+
+  if (unknownFields.size > 0) {
+    sb.append("\n")
+    repeat(depth + 1) { sb.append("  ") }
+    sb.append("unknownFields(").append(unknownFields.size).append(")")
+  }
+}
+
 /**
  * Recursively retrieves all inner complex proto types inside a given proto.
  */