From 47f9eef584390b1a5e7a5e923fbfe425e9560e35 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Fri, 10 Dec 2021 11:45:09 +0100
Subject: [PATCH] Improve `PDFDocument.checkLastPage` for documents with
 corrupt XRef tables (PR 14311, 14335 follow-up)

Rather than trying, and failing, to fetch the entire /Pages-tree for documents with corrupt XRef tables, let's fallback to indexing all objects *before* trying to invoke the `Catalog.getAllPageDicts` method.
---
 src/core/document.js | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/core/document.js b/src/core/document.js
index 0706eb888..5d7768a52 100644
--- a/src/core/document.js
+++ b/src/core/document.js
@@ -1344,7 +1344,7 @@ class PDFDocument {
         // Clear out the various caches to ensure that we haven't stored any
         // inconsistent and/or incorrect state, since that could easily break
         // subsequent `this.getPage` calls.
-        this._pagePromises.clear();
+        this._pagePromises.delete(0);
         await this.cleanup();
 
         throw new XRefParseException();
@@ -1380,20 +1380,23 @@ class PDFDocument {
       }
       await this.getPage(numPages - 1);
     } catch (reason) {
-      warn(`checkLastPage - invalid /Pages tree /Count: ${numPages}.`);
       // Clear out the various caches to ensure that we haven't stored any
       // inconsistent and/or incorrect state, since that could easily break
       // subsequent `this.getPage` calls.
+      this._pagePromises.delete(numPages - 1);
       await this.cleanup();
 
+      if (reason instanceof XRefEntryException && !recoveryMode) {
+        throw new XRefParseException();
+      }
+      warn(`checkLastPage - invalid /Pages tree /Count: ${numPages}.`);
+
       let pagesTree;
       try {
         pagesTree = await pdfManager.ensureCatalog("getAllPageDicts");
       } catch (reasonAll) {
-        if (reasonAll instanceof XRefEntryException) {
-          if (!recoveryMode) {
-            throw new XRefParseException();
-          }
+        if (reasonAll instanceof XRefEntryException && !recoveryMode) {
+          throw new XRefParseException();
         }
         catalog.setActualNumPages(1);
         return;