Fix link preview race condition

ts/test-electron/linkPreviews/linkPreviewFetch_test.ts

@@ -1354,5 +1354,70 @@ describe('link preview fetching', () => {
         })
       );
     });
+
+    it("doesn't read the image if the request was aborted before reading started", async () => {
+      const abortController = new AbortController();
+
+      const fixture = await readFixture('kitten-1-64-64.jpg');
+
+      const fakeFetch = stub().callsFake(() => {
+        const response = new Response(fixture, {
+          headers: {
+            'Content-Type': 'image/jpeg',
+            'Content-Length': fixture.length.toString(),
+          },
+        });
+        sinon
+          .stub(response, 'arrayBuffer')
+          .rejects(new Error('Should not be called'));
+        sinon.stub(response, 'blob').rejects(new Error('Should not be called'));
+        sinon.stub(response, 'text').rejects(new Error('Should not be called'));
+        sinon.stub(response, 'body').get(() => {
+          throw new Error('Should not be accessed');
+        });
+
+        abortController.abort();
+
+        return response;
+      });
+
+      assert.isNull(
+        await fetchLinkPreviewImage(
+          fakeFetch,
+          'https://example.com/img',
+          abortController.signal
+        )
+      );
+    });
+
+    it('returns null if the request was aborted after the image was read', async () => {
+      const abortController = new AbortController();
+
+      const fixture = await readFixture('kitten-1-64-64.jpg');
+
+      const fakeFetch = stub().callsFake(() => {
+        const response = new Response(fixture, {
+          headers: {
+            'Content-Type': 'image/jpeg',
+            'Content-Length': fixture.length.toString(),
+          },
+        });
+        const oldArrayBufferMethod = response.arrayBuffer.bind(response);
+        sinon.stub(response, 'arrayBuffer').callsFake(async () => {
+          const data = await oldArrayBufferMethod();
+          abortController.abort();
+          return data;
+        });
+        return response;
+      });
+
+      assert.isNull(
+        await fetchLinkPreviewImage(
+          fakeFetch,
+          'https://example.com/img',
+          abortController.signal
+        )
+      );
+    });
   });
 });