From 25bf504ff5239e6aa6eb9b3e28e661d2bf93bc56 Mon Sep 17 00:00:00 2001
From: Calixte Denizet <calixte.denizet@gmail.com>
Date: Thu, 10 Dec 2020 16:02:11 +0100
Subject: [PATCH] Be sure that CalculationOrder is either null or a non-empty
 array

---
 src/core/document.js       | 3 +++
 src/scripting_api/event.js | 4 ++--
 test/unit/document_spec.js | 8 ++++++++
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/core/document.js b/src/core/document.js
index 1cce067abbf93..4736a2839cfa1 100644
--- a/src/core/document.js
+++ b/src/core/document.js
@@ -1050,6 +1050,9 @@ class PDFDocument {
     }
 
     const ids = calculationOrder.filter(isRef).map(ref => ref.toString());
+    if (ids.length === 0) {
+      return shadow(this, "calculationOrderIds", null);
+    }
     return shadow(this, "calculationOrderIds", ids);
   }
 }
diff --git a/src/scripting_api/event.js b/src/scripting_api/event.js
index f96b0f75717fe..542f16121cc6d 100644
--- a/src/scripting_api/event.js
+++ b/src/scripting_api/event.js
@@ -150,7 +150,7 @@ class EventDispatcher {
   }
 
   calculateNow() {
-    if (this._calculationOrder.length === 0) {
+    if (!this._calculationOrder) {
       return;
     }
     const first = this._calculationOrder[0];
@@ -160,7 +160,7 @@ class EventDispatcher {
   }
 
   runCalculate(source, event) {
-    if (this._calculationOrder.length === 0) {
+    if (!this._calculationOrder) {
       return;
     }
 
diff --git a/test/unit/document_spec.js b/test/unit/document_spec.js
index 57ab015421b6f..cde9f5105f787 100644
--- a/test/unit/document_spec.js
+++ b/test/unit/document_spec.js
@@ -187,6 +187,14 @@ describe("document", function () {
       acroForm.set("CO", []);
       pdfDocument = getDocument(acroForm);
       expect(pdfDocument.calculationOrderIds).toEqual(null);
+
+      acroForm.set("CO", ["1", "2"]);
+      pdfDocument = getDocument(acroForm);
+      expect(pdfDocument.calculationOrderIds).toEqual(null);
+
+      acroForm.set("CO", ["1", Ref.get(1, 0), "2"]);
+      pdfDocument = getDocument(acroForm);
+      expect(pdfDocument.calculationOrderIds).toEqual(["1R"]);
     });
 
     it("should get field objects array or null", async function () {