Tinker

web/apps/photos/src/pages/gallery.tsx

@@ -21,8 +21,8 @@ import {
 } from "@/new/photos/components/gallery";
 import type { GalleryBarMode } from "@/new/photos/components/gallery/BarImpl";
 import {
-    getUniqueFiles,
     setDerivativeState,
+    uniqueFilesByID,
     useGalleryReducer,
 } from "@/new/photos/components/gallery/reducer";
 import { usePeopleStateSnapshot } from "@/new/photos/components/utils/ml";
@@ -436,7 +436,7 @@ export default function Gallery() {
         () =>
             setSearchCollectionsAndFiles({
                 collections: collections ?? [],
-                files: getUniqueFiles(files ?? []),
+                files: uniqueFilesByID(files ?? []),
             }),
         [collections, files],
     );
@@ -612,7 +612,7 @@ export default function Gallery() {
                 }
             }
             const pfSet = new Set(activePerson?.fileIDs ?? []);
-            filteredFiles = getUniqueFiles(
+            filteredFiles = uniqueFilesByID(
                 files.filter(({ id }) => {
                     if (!pfSet.has(id)) return false;
                     return true;
@@ -623,13 +623,13 @@ export default function Gallery() {
                 people: filteredVisiblePeople,
             };
         } else if (activeCollectionID === TRASH_SECTION) {
-            filteredFiles = getUniqueFiles([
+            filteredFiles = uniqueFilesByID([
                 ...trashedFiles,
                 ...files.filter((file) => tempDeletedFileIds?.has(file.id)),
             ]);
         } else {
             const baseFiles = barMode == "hidden-albums" ? hiddenFiles : files;
-            filteredFiles = getUniqueFiles(
+            filteredFiles = uniqueFilesByID(
                 baseFiles.filter((item) => {
                     if (tempDeletedFileIds?.has(item.id)) {
                         return false;

web/packages/new/photos/components/gallery/reducer.ts

@@ -326,19 +326,28 @@ export const setDerivativeState = (
     };
 };
 
-export function getUniqueFiles(files: EnteFile[]) {
-    const idSet = new Set<number>();
-    const uniqueFiles = files.filter((file) => {
-        if (!idSet.has(file.id)) {
-            idSet.add(file.id);
-            return true;
-        } else {
-            return false;
-        }
+/**
+ * File IDs themselves are unique across all the files for the user (in fact,
+ * they're unique across all the files in an Ente instance). However, we still
+ * can have multiple entries for the same file ID in our local database because
+ * the unit of account is not actually a file, but a "Collection File": a
+ * collection and file pair.
+ *
+ * For example, if the same file is symlinked into two collections, then we will
+ * have two "Collection File" entries for it, both with the same file ID, but
+ * with different collection IDs.
+ *
+ * This function returns files such that only one of these entries (arbitrarily
+ * picked in case of dupes) is returned.
+ */
+export const uniqueFilesByID = (files: EnteFile[]) => {
+    const seen = new Set<number>();
+    return files.filter(({ id }) => {
+        if (seen.has(id)) return false;
+        seen.add(id);
+        return true;
     });
-
-    return uniqueFiles;
-}
+};
 
 const getArchivedCollectionIDs = (collections: Collection[]) =>
     new Set<number>(
@@ -541,7 +550,7 @@ function getHiddenItemsSummary(
             .filter((collection) => isDefaultHiddenCollection(collection))
             .map((collection) => collection.id),
     );
-    const hiddenItems = getUniqueFiles(
+    const hiddenItems = uniqueFilesByID(
         hiddenFiles.filter((file) =>
             defaultHiddenCollectionIds.has(file.collectionID),
         ),
@@ -589,7 +598,7 @@ function getSectionSummaries(
 }
 
 function getArchivedSectionSummary(files: EnteFile[]): CollectionSummary {
-    const archivedFiles = getUniqueFiles(
+    const archivedFiles = uniqueFilesByID(
         files.filter((file) => isArchivedFile(file)),
     );
     return {
@@ -662,7 +671,7 @@ function getAllSectionVisibleFiles(
     files: EnteFile[],
     archivedCollections: Set<number>,
 ): EnteFile[] {
-    const allSectionVisibleFiles = getUniqueFiles(
+    const allSectionVisibleFiles = uniqueFilesByID(
         files.filter((file) => {
             if (
                 isArchivedFile(file) ||