Prevent unhandled rejections when cancelling an errored stream reader

src/core/worker_stream.js

@@ -55,7 +55,7 @@ class PDFWorkerStreamReader extends BasePDFStreamReader {
   }
 
   cancel(reason) {
-    this._reader.cancel(reason);
+    this._reader.cancel(reason).catch(() => {});
   }
 }
 
@@ -81,7 +81,7 @@ class PDFWorkerStreamRangeReader extends BasePDFStreamRangeReader {
   }
 
   cancel(reason) {
-    this._reader.cancel(reason);
+    this._reader.cancel(reason).catch(() => {});
   }
 }
 

src/display/fetch_stream.js

@@ -140,7 +140,7 @@ class PDFFetchStreamReader extends BasePDFStreamReader {
   }
 
   cancel(reason) {
-    this._reader?.cancel(reason);
+    this._reader?.cancel(reason).catch(() => {});
     this._abortController.abort();
   }
 }
@@ -186,7 +186,7 @@ class PDFFetchStreamRangeReader extends BasePDFStreamRangeReader {
   }
 
   cancel(reason) {
-    this._reader?.cancel(reason);
+    this._reader?.cancel(reason).catch(() => {});
     this._abortController.abort();
   }
 }

src/display/node_stream.js

@@ -99,7 +99,7 @@ class PDFNodeStreamReader extends BasePDFStreamReader {
   }
 
   cancel(reason) {
-    this._reader?.cancel(reason);
+    this._reader?.cancel(reason).catch(() => {});
   }
 }
 
@@ -138,7 +138,7 @@ class PDFNodeStreamRangeReader extends BasePDFStreamRangeReader {
   }
 
   cancel(reason) {
-    this._reader?.cancel(reason);
+    this._reader?.cancel(reason).catch(() => {});
   }
 }
 

test/unit/fetch_stream_spec.js

@@ -118,6 +118,40 @@ describe("fetch_stream", function () {
     expect(result2.value).toEqual(tailSize);
   });
 
+  it("cancel after a failed read doesn't cause an unhandled rejection", async function () {
+    spyOn(globalThis, "fetch").and.callFake(
+      async () =>
+        new Response(
+          new ReadableStream({
+            pull(controller) {
+              controller.error(new Error("Network error"));
+            },
+          }),
+          { status: 200 }
+        )
+    );
+    const stream = new PDFFetchStream({
+      url: getPdfUrl(),
+      rangeChunkSize: 32768,
+      disableStream: false,
+      disableRange: false,
+    });
+
+    const fullReader = stream.getFullReader();
+    const rangeReader = stream.getRangeReader(0, 32768);
+    await expectAsync(fullReader.read()).toBeRejectedWithError("Network error");
+    await expectAsync(rangeReader.read()).toBeRejectedWithError(
+      "Network error"
+    );
+
+    fullReader.cancel(new AbortException("Don't need fullReader."));
+    rangeReader.cancel(new AbortException("Don't need rangeReader."));
+    // Allow any unhandled rejections to be reported.
+    await new Promise(resolve => {
+      setTimeout(resolve, 0);
+    });
+  });
+
   describe("Redirects", function () {
     it("redirects allowed if all responses are same-origin", async function () {
       await testCrossOriginRedirects({

test/unit/node_stream_spec.js

@@ -153,4 +153,29 @@ describe("node_stream", function () {
     expect(isRangeSupported).toBeFalse();
     expect(len).toEqual(smallLength);
   });
+
+  it("cancel after a failed read doesn't cause an unhandled rejection", async function () {
+    // We point the stream at a directory instead of at a PDF file on purpose.
+    // Opening a directory succeeds, but reading from it fails (with EISDIR),
+    // so both the full reader and the range reader end up with an errored
+    // stream.
+    const stream = new PDFNodeStream({
+      url: new URL("./test/pdfs/", cwdURL),
+      rangeChunkSize: 65536,
+      disableStream: false,
+      disableRange: false,
+    });
+
+    const fullReader = stream.getFullReader();
+    const rangeReader = stream.getRangeReader(0, 65536);
+    await expectAsync(fullReader.read()).toBeRejected();
+    await expectAsync(rangeReader.read()).toBeRejected();
+
+    fullReader.cancel(new AbortException("Don't need fullReader."));
+    rangeReader.cancel(new AbortException("Don't need rangeReader."));
+    // Allow any unhandled rejections to be reported.
+    await new Promise(resolve => {
+      setTimeout(resolve, 0);
+    });
+  });
 });