From 68e1a8e506009e5dbd46148de30abff2e07d1576 Mon Sep 17 00:00:00 2001
From: Samuel Newman <mozzius@protonmail.com>
Date: Thu, 29 Jan 2026 22:02:32 +0200
Subject: [PATCH] revoke media URLs

---
 src/view/com/composer/Composer.tsx            |  2 ++
 .../com/composer/drafts/DraftsListDialog.tsx  | 17 ++++++++++---
 src/view/com/composer/drafts/state/storage.ts | 14 +++++++++++
 .../com/composer/drafts/state/storage.web.ts  | 24 ++++++++++++++++++-
 .../videos/VideoTranscodeBackdrop.tsx         |  2 +-
 5 files changed, 54 insertions(+), 5 deletions(-)

diff --git a/src/view/com/composer/Composer.tsx b/src/view/com/composer/Composer.tsx
index e42dce8cd7..ba70458ee4 100644
--- a/src/view/com/composer/Composer.tsx
+++ b/src/view/com/composer/Composer.tsx
@@ -142,6 +142,7 @@ import {
   useSaveDraftMutation,
 } from './drafts/state/queries'
 import {type DraftSummary} from './drafts/state/schema'
+import {revokeAllMediaUrls} from './drafts/state/storage'
 import {PostLanguageSelect} from './select-language/PostLanguageSelect'
 import {
   type AssetType,
@@ -504,6 +505,7 @@ export const ComposePost = ({
   const onClose = useCallback(() => {
     closeComposer()
     clearThumbnailCache(queryClient)
+    revokeAllMediaUrls()
   }, [closeComposer, queryClient])
 
   const handleSaveDraft = React.useCallback(async () => {
diff --git a/src/view/com/composer/drafts/DraftsListDialog.tsx b/src/view/com/composer/drafts/DraftsListDialog.tsx
index ca8fcbf820..a09517d3bd 100644
--- a/src/view/com/composer/drafts/DraftsListDialog.tsx
+++ b/src/view/com/composer/drafts/DraftsListDialog.tsx
@@ -14,6 +14,7 @@ import {IS_NATIVE} from '#/env'
 import {DraftItem} from './DraftItem'
 import {useDeleteDraftMutation, useDraftsQuery} from './state/queries'
 import {type DraftSummary} from './state/schema'
+import {revokeAllMediaUrls} from './state/storage'
 
 export function DraftsListDialog({
   control,
@@ -36,6 +37,12 @@ export function DraftsListDialog({
   const handleSelectDraft = useCallback(
     (summary: DraftSummary) => {
       control.close(() => {
+        // Revoke preview URLs
+        // It would be neater to do it in the `onClose` callback
+        // on the dialog itself, but this would wipe out the new ones
+        // that will be created by `onSelectDraft`
+        // ndb: if we miss any, it'll be handled by the composer closing
+        revokeAllMediaUrls()
         onSelectDraft(summary)
       })
     },
@@ -53,7 +60,11 @@ export function DraftsListDialog({
     () => (
       <Button
         label={_(msg`Back`)}
-        onPress={() => control.close()}
+        onPress={() => {
+          control.close(() => {
+            revokeAllMediaUrls()
+          })
+        }}
         size="small"
         color="primary"
         variant="ghost">
@@ -93,7 +104,7 @@ export function DraftsListDialog({
 
   const onEndReached = useCallback(() => {
     if (hasNextPage && !isFetchingNextPage) {
-      fetchNextPage()
+      void fetchNextPage()
     }
   }, [hasNextPage, isFetchingNextPage, fetchNextPage])
 
@@ -132,7 +143,7 @@ export function DraftsListDialog({
       <Dialog.InnerFlatList
         data={drafts}
         renderItem={renderItem}
-        keyExtractor={item => item.id}
+        keyExtractor={(item: DraftSummary) => item.id}
         ListHeaderComponent={web(header)}
         stickyHeaderIndices={web([0])}
         ListEmptyComponent={emptyComponent}
diff --git a/src/view/com/composer/drafts/state/storage.ts b/src/view/com/composer/drafts/state/storage.ts
index 3fddc60480..4a9b8b5847 100644
--- a/src/view/com/composer/drafts/state/storage.ts
+++ b/src/view/com/composer/drafts/state/storage.ts
@@ -155,3 +155,17 @@ export function clearMediaCache(): void {
   cachePopulated = false
   populateCachePromise = null
 }
+
+/**
+ * Revoke a media URL (no-op on native - only needed for web blob URLs)
+ */
+export function revokeMediaUrl(_url: string): void {
+  // No-op on native - file URIs don't need revocation
+}
+
+/**
+ * Revoke all media URLs (no-op on native - only needed for web blob URLs)
+ */
+export function revokeAllMediaUrls(): void {
+  // No-op on native - file URIs don't need revocation
+}
diff --git a/src/view/com/composer/drafts/state/storage.web.ts b/src/view/com/composer/drafts/state/storage.web.ts
index 67c46d89bf..62717e76d9 100644
--- a/src/view/com/composer/drafts/state/storage.web.ts
+++ b/src/view/com/composer/drafts/state/storage.web.ts
@@ -84,6 +84,11 @@ export async function saveMediaToLocal(
   }
 }
 
+/**
+ * Track blob URLs created by loadMediaFromLocal for cleanup
+ */
+const createdBlobUrls = new Set<string>()
+
 /**
  * Load a media file from IndexedDB
  * @returns A blob URL for the saved media
@@ -97,7 +102,10 @@ export async function loadMediaFromLocal(
     throw new Error(`Media file not found: ${localRefPath}`)
   }
 
-  return URL.createObjectURL(record.blob)
+  const url = URL.createObjectURL(record.blob)
+  logger.debug('Created blob URL', {url})
+  createdBlobUrls.add(url)
+  return url
 }
 
 /**
@@ -165,6 +173,20 @@ export function clearMediaCache(): void {
  */
 export function revokeMediaUrl(url: string): void {
   if (url.startsWith('blob:')) {
+    logger.debug('Revoking blob URL', {url})
     URL.revokeObjectURL(url)
+    createdBlobUrls.delete(url)
   }
 }
+
+/**
+ * Revoke all blob URLs created by loadMediaFromLocal.
+ * Call this when closing the drafts list dialog to prevent memory leaks.
+ */
+export function revokeAllMediaUrls(): void {
+  logger.debug(`Revoking ${createdBlobUrls.size} blob URLs`)
+  for (const url of createdBlobUrls) {
+    URL.revokeObjectURL(url)
+  }
+  createdBlobUrls.clear()
+}
diff --git a/src/view/com/composer/videos/VideoTranscodeBackdrop.tsx b/src/view/com/composer/videos/VideoTranscodeBackdrop.tsx
index db38a76d9b..3daf7954f7 100644
--- a/src/view/com/composer/videos/VideoTranscodeBackdrop.tsx
+++ b/src/view/com/composer/videos/VideoTranscodeBackdrop.tsx
@@ -9,7 +9,7 @@ export const RQKEY = 'video-thumbnail'
 
 export function clearThumbnailCache(queryClient: QueryClient) {
   clearCache().catch(() => {})
-  queryClient.resetQueries({queryKey: [RQKEY]})
+  void queryClient.resetQueries({queryKey: [RQKEY]})
 }
 
 export function VideoTranscodeBackdrop({uri}: {uri: string}) {