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fix: lazy-load attachment safety (MIME filter, isLoading reset) #5053

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Merged
siddseethepalli merged 1 commit into from
Feb 19, 2026
Merged

fix: lazy-load attachment safety (MIME filter, isLoading reset) #5053

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23 changes: 13 additions & 10 deletions assistant/src/daemon/handlers/sessions.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -348,17 +348,20 @@ export function handleHistoryRequest(
if (m.role === 'assistant' && m.id) {
const linked = getAttachmentsForMessageUnscoped(m.id);
if (linked.length > 0) {
// Skip embedding base64 data for attachments larger than 512KB to keep
// the history_response payload small enough for the client to decode
// reliably. The client fetches large attachment data lazily via HTTP.
// Skip embedding base64 data for large video attachments to keep the
// history_response payload small. Only videos have a lazy-fetch path on
// the client, so non-video attachments always keep their inline data.
const MAX_INLINE_B64_SIZE = 512 * 1024;
attachments = linked.map((a) => ({
id: a.id,
filename: a.originalFilename,
mimeType: a.mimeType,
data: a.dataBase64.length > MAX_INLINE_B64_SIZE ? '' : a.dataBase64,
...(a.dataBase64.length > MAX_INLINE_B64_SIZE ? { sizeBytes: a.sizeBytes } : {}),
}));
attachments = linked.map((a) => {
const omit = a.mimeType.startsWith('video/') && a.dataBase64.length > MAX_INLINE_B64_SIZE;
return {
id: a.id,
filename: a.originalFilename,
mimeType: a.mimeType,
data: omit ? '' : a.dataBase64,
...(omit ? { sizeBytes: a.sizeBytes } : {}),
};
});
}
}
return {
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18 changes: 15 additions & 3 deletions clients/macos/vellum-assistant/Features/Chat/MediaEmbeds/InlineVideoAttachmentView.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -189,13 +189,19 @@ struct InlineVideoAttachmentView: View {
do {
let base64 = try await fetchAttachmentData(port: port, attachmentId: attachmentId)
guard let data = Data(base64Encoded: base64) else {
await MainActor.run { isLoading = false }
await MainActor.run {
isLoading = false
failed = true
}
return
}
try data.write(to: destURL)
await MainActor.run { isLoading = false }
} catch {
await MainActor.run { isLoading = false }
await MainActor.run {
isLoading = false
failed = true
}
Comment on lines +201 to +204

@chatgpt-codex-connector chatgpt-codex-connector Bot Feb 19, 2026

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P2 Badge Avoid marking playback failed on save I/O errors

This catch handles both fetch failures and data.write(to: destURL) failures, so setting failed = true here can switch the attachment into the “Could not play video” state even when playback is actually fine and only the save destination failed (for example, permission denied or disk full). That regresses the user flow by turning a save-specific error into a persistent playback failure.

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}
}
} else {
Expand All @@ -211,7 +217,13 @@ struct InlineVideoAttachmentView: View {
Task {
do {
let base64 = try await fetchAttachmentData(port: port, attachmentId: attachmentId)
guard let data = Data(base64Encoded: base64) else { return }
guard let data = Data(base64Encoded: base64) else {
await MainActor.run {
isLoading = false
failed = true
}
return
}
let fileURL = safeTempURL()
try data.write(to: fileURL)
await MainActor.run {
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