Bug: API.internal.pages not updated when restoring a RenderTarget

[Opineppes]

Environment

• jsPDF version: 3.0.3
• nodejs: 20.19.0
• OS: Linux ubuntu 24

Description

When restoring a RenderTarget (e.g., after creating a FormObject), the internal reference API.internal.pages is not updated to reflect the restored pages array.

This results in a desynchronization between the internal rendering context and the public API (doc.internal.pages), which causes incorrect behavior in plugins or custom rendering logic that relies on the internal API.

Minimal code example

const doc = new jsPDF();

const pages1 = doc.internal.pages;

doc.beginFormObject( 0, 0, doc.internal.pageSize.width, context.internal.pageSize.height, context.Matrix( 1, 0, 0, 1, 0, 0 ) );
doc.endFormObject("myFormObject");

doc.addPage( "a4", "landscape" );

const pages2 = doc.internal.pages );

console.log( pages1, pages2, pages1 === pages2 );

Expected behavior

After restoring the previous render target,
API.internal.pages should be updated to reference the restored pages array,
so that the public and internal contexts stay in sync.

Actual behavior

API.internal.pages continues pointing to the old pages array created before beginFormObject().
This leads to inconsistencies when interacting with doc.internal.pages or plugins that use it.

Suspected cause

In RenderTarget.prototype.restore() (see snippet below),
the pages variable is reassigned,
but the internal API references (API.internal.pages) is not updated:

jsPDF/src/jspdf.js

Lines 5722 to 5733 in 463b199

	RenderTarget.prototype.restore = function() {
	page = this.page;
	currentPage = this.currentPage;
	pagesContext = this.pagesContext;
	pages = this.pages;
	pageX = this.x;
	pageY = this.y;
	pageMatrix = this.matrix;
	setPageWidthWithoutScaling(currentPage, this.width);
	setPageHeightWithoutScaling(currentPage, this.height);
	outputDestination = this.outputDestination;
	};

Suggested fix

Rebind API.internal.pages after restoring the render target:

RenderTarget.prototype.restore = function() {
  page = this.page;
  currentPage = this.currentPage;
  pagesContext = this.pagesContext;
  API.internal.pages = pages = this.pages;
  pageX = this.x;
  pageY = this.y;
  pageMatrix = this.matrix;
  setPageWidthWithoutScaling(currentPage, this.width);
  setPageHeightWithoutScaling(currentPage, this.height);
  outputDestination = this.outputDestination;
};

Why this matters

• Keeps the internal and public state consistent.
• Prevents plugins and internal tools that use API.internal.pages from breaking after a render target restore.
• Maintains predictable document behavior when working with FormObjects or custom render targets.

PS: Generated by chatgpt and edited by a Human

[HackbrettXXX]

Thanks for the bug report. If you provide a PR, I'll merge it. However, I suggest a safer fix: The pages property of the internal API object should be a getter resolving to the pages variable:

  API.internal = {
// ...
    get pages() { return pages },
// ...    
  };