From b01eeaf8e138e3541bda2f424b95170a6f88395c Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Tue, 21 Apr 2026 11:36:56 +0200
Subject: [PATCH] Improve the "CopyLocalImage" unit-tests

Rather than relying on the time it takes to parse/render the pages, which leads to intermittent failures, add a test-only property and use it to check if the "CopyLocalImage" code-path was exercised.
---
 src/display/api.js    |  6 +++++-
 test/unit/api_spec.js | 24 +++++++++---------------
 2 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/src/display/api.js b/src/display/api.js
index 6de590441..3cf541917 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -2794,7 +2794,11 @@ class WorkerTransport {
               if (!data.dataLen) {
                 return null;
               }
-              this.commonObjs.resolve(id, structuredClone(data));
+              const copy = structuredClone(data);
+              if (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) {
+                copy.CopyLocalImage = true;
+              }
+              this.commonObjs.resolve(id, copy);
               return data.dataLen;
             }
           }
diff --git a/test/unit/api_spec.js b/test/unit/api_spec.js
index d9c29732b..1be2c3037 100644
--- a/test/unit/api_spec.js
+++ b/test/unit/api_spec.js
@@ -4883,8 +4883,7 @@ have written that much by now. So, here’s to squashing bugs.`);
       const pdfDoc = await loadingTask.promise;
       const { canvasFactory } = pdfDoc;
       let checkedCopyLocalImage = false,
-        firstImgData = null,
-        firstStatsOverall = null;
+        firstImgData = null;
 
       for (let i = 1; i <= pdfDoc.numPages; i++) {
         const pdfPage = await pdfDoc.getPage(i);
@@ -4905,10 +4904,6 @@ have written that much by now. So, here’s to squashing bugs.`);
         // the image-data below.
         canvasFactory.destroy(canvasAndCtx);
 
-        const [statsOverall] = pdfPage.stats.times
-          .filter(time => time.name === "Overall")
-          .map(time => time.end - time.start);
-
         const { commonObjs, objs } = pdfPage;
         const imgIndex = opList.fnArray.indexOf(OPS.paintImageXObject);
         const [objId, width, height] = opList.argsArray[imgIndex];
@@ -4932,7 +4927,6 @@ have written that much by now. So, here’s to squashing bugs.`);
         // Ensure that the actual image data is identical for all pages.
         if (i === 1) {
           firstImgData = objs.get(objId);
-          firstStatsOverall = statsOverall;
 
           expect(firstImgData.width).toEqual(EXPECTED_WIDTH);
           expect(firstImgData.height).toEqual(EXPECTED_HEIGHT);
@@ -4958,10 +4952,9 @@ have written that much by now. So, here’s to squashing bugs.`);
           ).toEqual(true);
 
           if (i === NUM_PAGES_THRESHOLD) {
-            checkedCopyLocalImage = true;
-            // Ensure that the image was copied in the main-thread, rather
-            // than being re-parsed in the worker-thread (which is slower).
-            expect(statsOverall).toBeLessThan(firstStatsOverall / 2);
+            // Ensure that the image was copied in the main-thread (into
+            // commonObjs), rather than being re-parsed in the worker-thread.
+            checkedCopyLocalImage = currentImgData.CopyLocalImage;
           }
         }
       }
@@ -4969,7 +4962,6 @@ have written that much by now. So, here’s to squashing bugs.`);
 
       await loadingTask.destroy();
       firstImgData = null;
-      firstStatsOverall = null;
     });
 
     it("caches image resources at the document/page level, with main-thread copying of complex images (issue 11518)", async function () {
@@ -5011,11 +5003,13 @@ have written that much by now. So, here’s to squashing bugs.`);
           expect(objs.has(objId)).toEqual(true);
           expect(commonObjs.has(objId)).toEqual(false);
         } else if (i === NUM_PAGES_THRESHOLD) {
-          checkedCopyLocalImage = true;
-          // Ensure that the image was copied in the main-thread (into
-          // commonObjs), rather than being re-parsed in the worker-thread.
           expect(objs.has(objId)).toEqual(false);
           expect(commonObjs.has(objId)).toEqual(true);
+
+          // Ensure that the image was copied in the main-thread (into
+          // commonObjs), rather than being re-parsed in the worker-thread.
+          const imgData = commonObjs.get(objId);
+          checkedCopyLocalImage = imgData.CopyLocalImage;
         } else {
           break;
         }