From 98f570c103f95e74062cf1e406b843b869de38c8 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Thu, 7 Nov 2019 11:37:48 +0100
Subject: [PATCH] Prevent browser exceptions from incorrectly triggering the
 `assert` in `PDFPageProxy._abortOperatorList` (PR 11069 follow-up)

For certain canvas-related errors (and probably others), the browser rendering exceptions may be propagated "as-is" to the PDF.js code. In this case, the exceptions are of the somewhat cryptic `NS_ERROR_FAILURE` type.
Unfortunately these aren't actual `Error`s, which thus ends up unintentionally triggering the `assert` in `PDFPageProxy._abortOperatorList`; sorry about that!
---
 src/display/api.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/display/api.js b/src/display/api.js
index eedac49db..3514d9efa 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -1378,7 +1378,8 @@ class PDFPageProxy {
    * @private
    */
   _abortOperatorList({ intentState, reason, force = false, }) {
-    assert(reason instanceof Error,
+    assert(reason instanceof Error ||
+           (typeof reason === 'object' && reason !== null),
            'PDFPageProxy._abortOperatorList: Expected "reason" argument.');
 
     if (!intentState.streamReader) {