feat(attachments): expose fetchSource on preview and mesh retry

Add readAttachmentBytesWithSource so callers know whether bytes came from
local staging, drive-local, protomux attach-mesh, or hyperdrive replication.

readAttachmentPreview now returns fetchSource for UI and smokes.
_fetchAttachMeshWithRetry mirrors banner prefetch (14s timeout + 600ms retry
when attach sessions exist). Banner prefetch uses the same retry helper.

Phase 60 / v0.8.25 — Pear attach preview mesh path.

Co-authored-by: Cursor <[email protected]>

index.js

@@ -621,7 +621,7 @@ class PearcordPlatform extends EventEmitter {
     const row = await this.attachments.get(attachmentId)
     if (row && this.attachments.hasLocalBytes(row)) return row
     if (!this.guild) return null
-    const buf = await this.guild.fetchAttachmentFromPeers(attachmentId).catch(() => null)
+    const buf = await this._fetchAttachMeshWithRetry(attachmentId)
     if (!buf) return null
     const meta = row || (await this.attachments.get(attachmentId))
     if (!meta) return null
@@ -2124,21 +2124,33 @@ class PearcordPlatform extends EventEmitter {
     return row
   }
 
-  async readAttachmentBytes (attachmentId) {
+  async _fetchAttachMeshWithRetry (attachmentId, timeoutMs = 14000) {
+    if (!this.guild) return null
+    let buf = await this.guild.fetchAttachmentFromPeers(attachmentId, timeoutMs).catch(() => null)
+    if (buf?.length) return buf
+    if (!(this.guild._attachChannels?.size > 0)) return null
+    await new Promise((r) => setTimeout(r, 600))
+    return this.guild.fetchAttachmentFromPeers(attachmentId, timeoutMs).catch(() => null)
+  }
+
+  async readAttachmentBytesWithSource (attachmentId) {
     const row = await this.attachments?.get(attachmentId)
     if (!row) throw new Error('attachment not found')
     if (this.attachments.hasLocalBytes(row)) {
-      return this.attachments.readBytes(row)
+      return { buf: await this.attachments.readBytes(row), source: 'local' }
     }
     const drive = getGuildDrive(this.storagePath, row.guildId)
     const localDrive = await drive.get(row.id, row.filename, row.drivePath)
-    if (localDrive?.length) return localDrive
+    if (localDrive?.length) {
-
+      return { buf: localDrive, source: 'drive-local' }
-    let buf = null
-    if (this.guild) {
-      buf = await this.guild.fetchAttachmentFromPeers(attachmentId).catch(() => null)
     }
-    if (!buf && isHexDriveKey(row.driveKey) && (this.guild?.peers?.size || 0) > 0) {
+
+    let buf = await this._fetchAttachMeshWithRetry(attachmentId)
+    if (buf?.length) {
+      await this.attachments.persistFetched(row, buf)
+      return { buf, source: 'attach-mesh' }
+    }
+    if (isHexDriveKey(row.driveKey) && (this.guild?.peers?.size || 0) > 0) {
       buf = await drive.fetchRemote({
         driveKey: row.driveKey,
         drivePath: row.drivePath,
@@ -2147,9 +2159,16 @@ class PearcordPlatform extends EventEmitter {
         swarm: this.guild?.swarm,
         timeoutMs: 8000
       })
+      if (buf?.length) {
+        await this.attachments.persistFetched(row, buf)
+        return { buf, source: 'hyperdrive' }
+      }
     }
-    if (!buf) throw new Error('attachment file missing')
+    throw new Error('attachment file missing')
-    await this.attachments.persistFetched(row, buf)
+  }
+
+  async readAttachmentBytes (attachmentId) {
+    const { buf } = await this.readAttachmentBytesWithSource(attachmentId)
     return buf
   }
 
@@ -2159,12 +2178,13 @@ class PearcordPlatform extends EventEmitter {
     if (!String(row.mimeType || '').startsWith('image/')) {
       throw new Error('preview only for images')
     }
-    const buf = await this.readAttachmentBytes(attachmentId)
+    const { buf, source } = await this.readAttachmentBytesWithSource(attachmentId)
     return {
       attachmentId: row.id,
       mimeType: row.mimeType,
       filename: row.filename,
-      dataBase64: b4a.toString(buf, 'base64')
+      dataBase64: b4a.toString(buf, 'base64'),
+      fetchSource: source
     }
   }