fix(library): draw one tile for a frame a catalogue holds under both spellings

docker/frontend/scripts/legacy-dup-check.mjs

@@ -218,6 +218,14 @@ await page.waitForSelector('[data-key^="lib-node-"]', { timeout: 60_000 });
 const before = await rows();
 step('the doubled catalogue is read', before.photos.length === names.length * 2, `${before.photos.length} rows: ${before.photos.map((p) => p.id).join(' | ')}`);
 
+// The wall, before any repair: the frames of the drive are drawn once each, even
+// while the catalogue holds two rows for every one of them.
+await page.locator('[data-key^="lib-node-"]').first().click();
+await page.click('[data-key="lib-view-grid"]');
+await page.waitForTimeout(3000);
+const tiles = await page.evaluate(() => document.querySelectorAll('.lib-tile, .mob-lib-thumb-cell').length);
+step('the wall draws each frame once', tiles === names.length, `tiles=${tiles}`);
+
 // UPDATE on the drive row.
 await page.locator('[data-key^="lib-node-"]').first().click({ button: 'right' });
 await page.waitForSelector('[data-key^="lib-update-"]', { timeout: 20_000 });

docker/frontend/src/engine/library.ts

@@ -2541,7 +2541,7 @@ export async function readPhotos(
     // being filed twice and `prunePhotos` to drop against the spelling that
     // stands. See both.
     const raw = folder !== undefined && folder !== root ? folder : null;
-    const rows: LibraryPhoto[] = [];
+    let rows: LibraryPhoto[] = [];
     let emittedFirst = false;
 
     const sweep = async (base: string): Promise<void> => {
@@ -2578,6 +2578,25 @@ export async function readPhotos(
 
     await sweep(root ?? '');
     if (raw) await sweep(raw);
+    // A catalogue that holds a frame twice — under the id this build computes and
+    // under the spelling a build before it filed it under — is one frame the
+    // reader is drawn twice, and this is the read that hands the wall both. The
+    // two are one path once `normPath` has had them, and what the reader is handed
+    // is the row that is filed under the path it spells: the other is left where
+    // it is, and the next reading of that disk drops it. See `prunePhotos`. The
+    // reading of one folder keeps both, because that is the reading that has the
+    // frame in hand and the one the drop is made from.
+    if (folder === undefined) {
+      const shown = new Set(rows.filter((p) => p.id === normPath(p.id)).map((p) => p.id));
+      const seen = new Set<string>();
+      rows = rows.filter((p) => {
+        const key = normPath(p.id);
+        if (shown.has(key)) return p.id === key;
+        if (seen.has(key)) return false;
+        seen.add(key);
+        return true;
+      });
+    }
     rows.sort((a, b) => b.taken - a.taken);
     if (!folder) {
       cached = rows;