Ensure no invisible displayName will be used

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/sender/SenderInfo.kt

@@ -16,6 +16,8 @@
 
 package org.matrix.android.sdk.api.session.room.sender
 
+import org.matrix.android.sdk.internal.util.replaceSpaceChars
+
 data class SenderInfo(
         val userId: String,
         /**
@@ -27,7 +29,8 @@ data class SenderInfo(
 ) {
     val disambiguatedDisplayName: String
         get() = when {
-            displayName.isNullOrBlank() -> userId
+            displayName == null                       -> userId
+            displayName.replaceSpaceChars().isBlank() -> "$displayName ($userId)"
             isUniqueDisplayName                       -> displayName
             else                                      -> "$displayName ($userId)"
         }

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/util/StringUtils.kt

@@ -71,3 +71,10 @@ fun String.caseInsensitiveFind(subString: String): Boolean {
 
     return false
 }
+
+internal val spaceChars = "[\u00A0\u2000-\u200B\u2800\u3000]".toRegex()
+
+/**
+ * Strip all the UTF-8 chars which are actually spaces
+ */
+internal fun String.replaceSpaceChars() = replace(spaceChars, "")

vector/src/main/java/im/vector/app/features/media/BaseAttachmentProvider.kt

@@ -83,7 +83,7 @@ abstract class BaseAttachmentProvider<Type>(
             val dateString = dateFormatter.format(timelineEvent.root.originServerTs, DateFormatKind.DEFAULT_DATE_AND_TIME)
             overlayView?.updateWith(
                     counter = stringProvider.getString(R.string.attachment_viewer_item_x_of_y, position + 1, getItemCount()),
-                    senderInfo = "${timelineEvent.senderInfo.displayName} $dateString"
+                    senderInfo = "${timelineEvent.senderInfo.disambiguatedDisplayName} $dateString"
             )
             overlayView?.views?.overlayVideoControlsGroup?.isVisible = timelineEvent.root.isVideoMessage()
         } else {