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Fix image flickering on message updates #6307

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0119d33
Fix image flickering on message update.
VelikovPetar Mar 30, 2026
55d9cb4
Merge branch 'v7' into bug/fix_image_flciker_on_message_updates
VelikovPetar Mar 30, 2026
4f08468
Merge branch 'v7' into bug/fix_image_flciker_on_message_updates
VelikovPetar Mar 31, 2026
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2 changes: 1 addition & 1 deletion ...chat/android/client/internal/state/message/attachments/internal/AttachmentUrlValidator.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -32,7 +32,7 @@ internal class AttachmentUrlValidator(private val attachmentHelper: AttachmentHe
return newMessages.map { newMessage -> updateValidAttachmentsUrl(newMessage, oldMessages[newMessage.id]) }
}

private fun updateValidAttachmentsUrl(newMessage: Message, oldMessage: Message?): Message {
internal fun updateValidAttachmentsUrl(newMessage: Message, oldMessage: Message?): Message {
return if (newMessage.attachments.isEmpty() || oldMessage == null) {
newMessage
} else {
Expand Down
4 changes: 2 additions & 2 deletions ...at/android/client/internal/state/plugin/logic/channel/internal/ChannelEventHandlerImpl.kt
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Expand Up @@ -398,8 +398,8 @@ internal class ChannelEventHandlerImpl(
}

private fun updateMessageWithReaction(message: Message) {
state.updateMessageById(message.id) { oldMessage ->
message.copy(ownReactions = oldMessage.ownReactions)
state.updateMessageFromEvent(message) { old, new ->
new.copy(ownReactions = old.ownReactions)
}
}

Expand Down
10 changes: 5 additions & 5 deletions ...ream/chat/android/client/internal/state/plugin/logic/channel/internal/ChannelLogicImpl.kt
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Expand Up @@ -313,20 +313,20 @@ internal class ChannelLogicImpl(
// User's window was already trimmed away from the latest (insideSearch set by
// trimNewestMessages, or a prior jump-to-message). Stay at current position;
// refresh the "jump to latest" cache with the server's current latest page.
state.upsertCachedLatestMessages(sortedMessages)
state.upsertCachedLatestMessages(sortedMessages, preserveAttachmentUrls = true)
}
hasGap(currentMessages, sortedMessages) -> {
// Incoming page is newer than the current window with no overlap. Inserting the
// incoming messages would create a fragmented list. Instead, treat the user's
// position as a mid-page: store the incoming as the "latest" cache and signal the UI.
state.upsertCachedLatestMessages(sortedMessages)
state.upsertCachedLatestMessages(sortedMessages, preserveAttachmentUrls = true)
state.setInsideSearch(true)
state.paginationManager.setEndOfNewerMessages(false)
}
else -> {
// Incoming messages are contiguous with (or overlap) the current window.
// Upsert preserves the user's scroll position while adding/updating messages.
state.upsertMessages(sortedMessages)
state.upsertMessages(sortedMessages, preserveAttachmentUrls = true)
state.paginationManager.setEndOfOlderMessages(channel.messages.size < messageLimit)
}
}
Expand Down Expand Up @@ -382,7 +382,7 @@ internal class ChannelLogicImpl(
}

query.isFilteringNewerMessages() -> {
// Loading newer messages - upsert
// Loading newer messages - append
state.upsertMessages(channel.messages)
state.trimOldestMessages()
val endReached = query.messagesLimit() > channel.messages.size
Expand All @@ -394,7 +394,7 @@ internal class ChannelLogicImpl(
}

query.filteringOlderMessages() -> {
// Loading older messages - prepend; ceiling does not change
// Loading older messages - prepend
state.upsertMessages(channel.messages)
state.trimNewestMessages()
}
Expand Down
85 changes: 79 additions & 6 deletions ...ream/chat/android/client/internal/state/plugin/state/channel/internal/ChannelStateImpl.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,7 @@ import io.getstream.chat.android.client.extensions.getCreatedAtOrDefault
import io.getstream.chat.android.client.extensions.getCreatedAtOrNull
import io.getstream.chat.android.client.extensions.internal.updateUsers
import io.getstream.chat.android.client.extensions.internal.wasCreatedAfter
import io.getstream.chat.android.client.internal.state.message.attachments.internal.AttachmentUrlValidator
import io.getstream.chat.android.client.internal.state.plugin.state.channel.internal.ChannelStateImpl.Companion.CACHED_LATEST_MESSAGES_LIMIT
import io.getstream.chat.android.client.internal.state.plugin.state.channel.internal.ChannelStateImpl.Companion.TRIM_BUFFER
import io.getstream.chat.android.client.internal.state.utils.internal.combineStates
Expand Down Expand Up @@ -88,6 +89,7 @@ internal class ChannelStateImpl(
private val liveLocations: StateFlow<List<Location>>,
private val messageLimit: Int?,
val paginationManager: MessagesPaginationManager = MessagesPaginationManagerImpl(),
private val attachmentUrlValidator: AttachmentUrlValidator = AttachmentUrlValidator(),
) : ChannelState {

override val cid: String = "$channelType:$channelId"
Expand Down Expand Up @@ -321,6 +323,8 @@ internal class ChannelStateImpl(
/**
* Upserts a single message into the current state.
* Uses optimized single-element upsert with binary search insertion.
* When updating an existing message, valid attachment URLs from the old message are preserved
* to prevent unnecessary image reloads caused by CDN signature changes.
*
* @param message The message to upsert.
*/
Expand All @@ -334,6 +338,7 @@ internal class ChannelStateImpl(
element = message,
idSelector = Message::id,
comparator = MESSAGE_COMPARATOR,
update = { old -> preserveAttachmentUrls(message, old) },
)
}
// Update can be called for "ephemeral" messages (ex. Shuffle Giphy)
Expand All @@ -343,6 +348,7 @@ internal class ChannelStateImpl(
element = message,
idSelector = Message::id,
comparator = MESSAGE_COMPARATOR,
update = { old -> preserveAttachmentUrls(message, old) },
)
}
}
Expand All @@ -356,8 +362,11 @@ internal class ChannelStateImpl(
* This is guaranteed when messages come from API responses or database queries.
*
* @param messages The list of messages to upsert (must be sorted by createdAt).
* @param preserveAttachmentUrls When `true`, valid attachment URLs from existing messages in state are
* preserved to prevent unnecessary image reloads caused by CDN signature changes. Defaults to `false`
* for pagination performance; set to `true` for reconnection/sync paths where messages may overlap.
*/
fun upsertMessages(messages: List<Message>) {
fun upsertMessages(messages: List<Message>, preserveAttachmentUrls: Boolean = false) {
val messagesToUpsert = messages.filterNot { shouldIgnoreUpsertion(it) }
if (messagesToUpsert.isEmpty()) return
for (message in messagesToUpsert) {
Expand All @@ -366,8 +375,13 @@ internal class ChannelStateImpl(
message.poll?.let { registerPollForMessage(it, message.id) }
}
_messages.update { current ->
val enriched = if (preserveAttachmentUrls) {
preserveAttachmentUrls(messagesToUpsert, current)
} else {
messagesToUpsert
}
current.mergeSorted(
other = messagesToUpsert,
other = enriched,
idSelector = Message::id,
comparator = MESSAGE_COMPARATOR,
)
Expand All @@ -377,7 +391,8 @@ internal class ChannelStateImpl(
/**
* Upserts a single message into the cached latest messages state.
* The cached messages are bounded to [CACHED_LATEST_MESSAGES_LIMIT] to prevent unbounded growth
* while the user is in search mode.
* while the user is in search mode. When updating an existing message, valid attachment URLs
* from the old message are preserved to prevent unnecessary image reloads.
*
* @param message The message to upsert.
*/
Expand All @@ -392,17 +407,22 @@ internal class ChannelStateImpl(
maxSize = CACHED_LATEST_MESSAGES_LIMIT,
idSelector = Message::id,
comparator = MESSAGE_COMPARATOR,
update = { old -> preserveAttachmentUrls(message, old) },
)
}
}

/**
* Updates a message in the current state. Does nothing if the message does not exist.
* Valid attachment URLs from the existing message are preserved to prevent unnecessary
* image reloads caused by CDN signature changes.
*
* @param message The message to update.
*/
fun updateMessage(message: Message) {
updateMessageById(message.id) { message }
updateMessageById(message.id) { old ->
preserveAttachmentUrls(message, old)
}
Comment on lines 422 to +425
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@coderabbitai coderabbitai bot Mar 30, 2026

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⚠️ Potential issue | 🟡 Minor

The URL-preserved Message never escapes these helpers.

Both update paths only apply preserveAttachmentUrls(...) inside the internal lists. Callers still hold the raw event payload, so any secondary fan-out can reintroduce the re-signed imageUrl; MessageUpdatedEvent -> updateQuotedMessageReferences(...) is the current example, which means quoted reply previews can still flicker. Return the merged Message, or preserve again inside updateQuotedMessageReferences.

Also applies to: 457-459

🤖 Prompt for AI Agents 
Verify each finding against the current code and only fix it if needed.

In
`@stream-chat-android-client/src/main/java/io/getstream/chat/android/client/internal/state/plugin/state/channel/internal/ChannelStateImpl.kt`
around lines 422 - 425, The preserved-URL Message produced by
preserveAttachmentUrls(...) is only applied inside internal lists and never
returned to callers, so external code (e.g., updateQuotedMessageReferences) can
still see and propagate the original re-signed imageUrl; modify updateMessage
and the other update path (the one at lines indicated in the review) so that
updateMessageById(...) returns the merged/updated Message (apply
preserveAttachmentUrls and return that Message) and propagate that returned
Message out to callers, or alternatively call preserveAttachmentUrls again
inside updateQuotedMessageReferences(...) to ensure quoted/secondary fan-out
always receives the URL-preserved Message; reference the functions
updateMessage, updateMessageById, preserveAttachmentUrls, and
updateQuotedMessageReferences when making the change.

}

/**
Expand All @@ -419,6 +439,27 @@ internal class ChannelStateImpl(
_pinnedMessages.update { it.updateIf({ msg -> msg.id == id }, transform) }
}

/**
* Replaces an existing message with [eventMessage] while preserving valid attachment URLs
* from the old message, then applies the [enrich] function for caller-specific field merging.
*
* Use this for event-driven full-message replacements (e.g. reaction events) where the event
* payload may carry attachment URLs with different CDN signatures than the ones already in state.
*
* @param eventMessage The new message from the event payload.
* @param enrich A function that receives the old message and the URL-preserved new message,
* returning the final merged message. Typically used to preserve fields like `ownReactions`.
*/
fun updateMessageFromEvent(
eventMessage: Message,
enrich: (old: Message, new: Message) -> Message,
) {
updateMessageById(eventMessage.id) { old ->
val urlPreserved = preserveAttachmentUrls(eventMessage, old)
enrich(old, urlPreserved)
}
}

/**
* Hard deletes a message from the current state.
* Note: Soft deletes are handled via [updateMessage].
Expand Down Expand Up @@ -661,6 +702,8 @@ internal class ChannelStateImpl(

/**
* Adds pinned messages to the current pinned messages list.
* When updating an existing pinned message, valid attachment URLs from the old message
* are preserved to prevent unnecessary image reloads caused by CDN signature changes.
*
* @param pinnedMessages The list of pinned messages to add.
*/
Expand All @@ -679,6 +722,7 @@ internal class ChannelStateImpl(
element = pinnedMessage,
idSelector = Message::id,
comparator = compareBy { it.pinnedAt },
update = { old -> preserveAttachmentUrls(pinnedMessage, old) },
)
}
result
Expand Down Expand Up @@ -1411,14 +1455,24 @@ internal class ChannelStateImpl(
*
* Called during reconnection to refresh the "jump to latest" cache with the server's
* current latest page without disturbing the user's active scroll position.
*
* @param messages The list of messages to merge.
* @param preserveAttachmentUrls When `true`, valid attachment URLs from existing cached messages are
* preserved to prevent unnecessary image reloads caused by CDN signature changes. Defaults to `false`;
* set to `true` for reconnection/sync paths where messages may overlap.
*/
fun upsertCachedLatestMessages(messages: List<Message>) {
fun upsertCachedLatestMessages(messages: List<Message>, preserveAttachmentUrls: Boolean = false) {
if (messages.isEmpty()) return
val messagesToUpsert = messages.filterNot { shouldIgnoreUpsertion(it) }
if (messagesToUpsert.isEmpty()) return
_cachedLatestMessages.update { current ->
val enriched = if (preserveAttachmentUrls) {
preserveAttachmentUrls(messagesToUpsert, current)
} else {
messagesToUpsert
}
current.mergeSorted(
other = messagesToUpsert,
other = enriched,
idSelector = Message::id,
comparator = MESSAGE_COMPARATOR,
).takeLast(CACHED_LATEST_MESSAGES_LIMIT)
Expand Down Expand Up @@ -1556,6 +1610,25 @@ internal class ChannelStateImpl(
FROM_NEWEST,
}

/**
* Preserves valid attachment URLs from [oldMessage] onto [newMessage].
* Prevents unnecessary image reloads when the backend delivers events with different CDN signatures.
*/
private fun preserveAttachmentUrls(newMessage: Message, oldMessage: Message): Message =
attachmentUrlValidator.updateValidAttachmentsUrl(newMessage, oldMessage)

/**
* Preserves valid attachment URLs for a batch of messages.
* Builds a lookup map from [oldMessages] and enriches each message in [newMessages].
*/
private fun preserveAttachmentUrls(
newMessages: List<Message>,
oldMessages: List<Message>,
): List<Message> {
val oldById = oldMessages.associateBy(Message::id)
return attachmentUrlValidator.updateValidAttachmentsUrl(newMessages, oldById)
}

private companion object {
/**
* Hard limit for cached latest messages to prevent unbounded memory growth while in search mode.
Expand Down
3 changes: 2 additions & 1 deletion ...ient/src/main/java/io/getstream/chat/android/client/internal/state/utils/internal/List.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -148,8 +148,9 @@ internal fun <T, ID> List<T>.upsertSortedBounded(
maxSize: Int,
idSelector: (T) -> ID,
comparator: Comparator<in T>,
update: (old: T) -> T = { element },
): List<T> {
val result = upsertSorted(element, idSelector, comparator)
val result = upsertSorted(element, idSelector, comparator, update)
return if (result.size > maxSize) result.takeLast(maxSize) else result
}

Expand Down
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