From 43dd2781a0dc9dec7786c8517854ec3b9fee61de Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Sun, 7 Jun 2026 11:28:57 +0200
Subject: [PATCH] Prevent intermittent issues when invoking the
 `PDFPageView.prototype.#injectLinkAnnotations` method

Looking at the coverage data there are cases where we attempt to insert inferred link-annotations *before* the annotationLayer has rendered, see [here](https://app.codecov.io/gh/mozilla/pdf.js/commit/23483658744d35fd56cf71b9129cd7d8718ecafd/blob/web/annotation_layer_builder.js?dropdown=coverage#L246), which shouldn't happen and why that's treated as an Error.

This is most likely caused by the asynchronicity of all the relevant code, since the `Autolinker` functionality can only be invoked after both the annotationLayer *and* the textLayer have finished rendering.
Given that those operations are asynchronous, by the time that they complete it's possible that the annotationLayer (and also the textLayer) has been replaced by a new instance. In that case we might thus attempt to inject inferred link-annotations before the "new" annotationLayer has rendered.

To avoid this intermittent issue, we now ensure that the annotationLayer and textLayer haven't changed between those layers rendering and the `Autolinker` functionality being invoked. (If they did change, then a future `render` call will trigger the inferred link-annotations handling).
---
 web/pdf_page_view.js | 37 ++++++++++++++++---------------------
 1 file changed, 16 insertions(+), 21 deletions(-)

diff --git a/web/pdf_page_view.js b/web/pdf_page_view.js
index 965fc29ab..58958f3d1 100644
--- a/web/pdf_page_view.js
+++ b/web/pdf_page_view.js
@@ -461,7 +461,9 @@ class PDFPageView extends BasePDFPageView {
     });
   }
 
-  async #renderAnnotationLayer() {
+  async #renderAnnotationLayer(textLayerPromise = null) {
+    const { annotationLayer, textLayer } = this;
+
     let error = null;
     try {
       await this.annotationLayer.render({
@@ -476,6 +478,10 @@ class PDFPageView extends BasePDFPageView {
     } finally {
       this.#dispatchLayerRendered("annotationlayerrendered", error);
     }
+
+    if (this.#enableAutoLinking && textLayerPromise) {
+      this.#injectLinkAnnotations(textLayerPromise, annotationLayer, textLayer);
+    }
   }
 
   async #renderAnnotationEditorLayer() {
@@ -532,9 +538,6 @@ class PDFPageView extends BasePDFPageView {
   }
 
   async #renderTextLayer() {
-    if (!this.textLayer) {
-      return;
-    }
     let error = null;
     try {
       await this.textLayer.render({
@@ -568,10 +571,6 @@ class PDFPageView extends BasePDFPageView {
    * aria-owns to work.
    */
   async #renderStructTreeLayer() {
-    if (!this.textLayer) {
-      return;
-    }
-
     const treeDom = await this.structTreeLayer?.render();
     if (treeDom) {
       this.l10n.pause();
@@ -595,24 +594,25 @@ class PDFPageView extends BasePDFPageView {
     this._textHighlighter.enable();
   }
 
-  async #injectLinkAnnotations(textLayerPromise) {
+  async #injectLinkAnnotations(textLayerPromise, annotationLayer, textLayer) {
     let error = null;
     try {
       await textLayerPromise;
 
-      if (!this.annotationLayer) {
+      if (
+        annotationLayer !== this.annotationLayer ||
+        textLayer !== this.textLayer
+      ) {
         return; // Rendering was cancelled while the textLayerPromise resolved.
       }
-      await this.annotationLayer.injectLinkAnnotations(
+      await annotationLayer.injectLinkAnnotations(
         Autolinker.processLinks(this)
       );
     } catch (ex) {
       console.error("#injectLinkAnnotations:", ex);
       error = ex;
     }
-    if (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) {
-      this.#dispatchLayerRendered("linkannotationsadded", error);
-    }
+    this.#dispatchLayerRendered("linkannotationsadded", error);
   }
 
   _resetCanvas() {
@@ -1192,14 +1192,10 @@ class PDFPageView extends BasePDFPageView {
         viewport.rawDims
       );
 
-      const textLayerPromise = this.#renderTextLayer();
+      const textLayerPromise = this.textLayer ? this.#renderTextLayer() : null;
 
       if (this.annotationLayer) {
-        await this.#renderAnnotationLayer();
-
-        if (this.#enableAutoLinking && this.annotationLayer && this.textLayer) {
-          await this.#injectLinkAnnotations(textLayerPromise);
-        }
+        await this.#renderAnnotationLayer(textLayerPromise);
       }
 
       this.drawLayer ||= new DrawLayerBuilder({
@@ -1216,7 +1212,6 @@ class PDFPageView extends BasePDFPageView {
       if (!annotationEditorUIManager) {
         return;
       }
-
       if (
         this.annotationLayer ||
         this.#annotationMode === AnnotationMode.DISABLE