Skip downloads that were aborted while queued

A download aborted by invalidation or a cache directory change while it
was still waiting in the concurrency limiter previously started anyway:
downloadFile only listened for future abort events and never checked
signal.aborted. The raced transfer held a download slot and, once the
inactivity or deadline timeout hit, could settle the URL with a
permanently persisted timeout error. Reject up front with the same
retryable 'Request aborted' error the mid-flight abort path reports.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016Q2tBCuePZJeeCkDDxu1m3

Author: jlobue10

packages/gui/src/electron/utils/downloadFile.test.ts

@@ -0,0 +1,31 @@
+import os from 'node:os';
+import path from 'node:path';
+
+const mockNetRequest = jest.fn();
+
+jest.mock('electron', () => ({
+  net: {
+    request: mockNetRequest,
+  },
+}));
+
+const downloadFile = jest.requireActual<typeof import('./downloadFile')>('./downloadFile').default;
+
+describe('downloadFile', () => {
+  beforeEach(() => {
+    mockNetRequest.mockReset();
+  });
+
+  it('does not start a transfer whose signal was aborted while queued', async () => {
+    const abortController = new AbortController();
+    abortController.abort();
+
+    await expect(
+      downloadFile('https://example.com/nft.png', path.join(os.tmpdir(), 'downloadFile-test-nft.png'), {
+        signal: abortController.signal,
+      }),
+    ).rejects.toThrow('Request aborted');
+
+    expect(mockNetRequest).not.toHaveBeenCalled();
+  });
+});

packages/gui/src/electron/utils/downloadFile.ts

@@ -90,6 +90,15 @@ export default async function downloadFile(
     throw new Error('Invalid URL');
   }
 
+  // A queued download can be aborted (invalidation, cache directory change)
+  // before the concurrency limiter starts it. Without this check the transfer
+  // would still run, hold a download slot, and could settle the URL with a
+  // permanent timeout error. The error matches the mid-flight abort message so
+  // the cache treats it as retryable.
+  if (signal?.aborted) {
+    throw new Error('Request aborted');
+  }
+
   const tempFilePath = `${localPath}.tmp`;
   const request = net.request(url);
   const outputStream = new WriteStreamPromise(tempFilePath, overrideFile);