Off-By-One `RangeError` Crash and Text Duplication in `StyleManager.editLink` and `deleteLink`

What’s broken?

In @blocknote/core, StyleManager.editLink and StyleManager.deleteLink perform an unconditional position + 1 lookup when locating the link mark at the current cursor position:

Inside packages/core/src/editor/managers/StyleManager.ts:220-260:

ts
public editLink(
  url: string,
  text: string,
  position = this.editor.transact((tr) => tr.selection.anchor),
) {
  this.editor.transact((tr) => {
    const linkData = this.getLinkMarkAtPos(position + 1);
    const { from, to } = linkData || {
      from: tr.selection.from,
      to: tr.selection.to,
    };

and in deleteLink:

public deleteLink(
  position = this.editor.transact((tr) => tr.selection.anchor),
) {
  this.editor.transact((tr) => {
    const linkData = this.getLinkMarkAtPos(position + 1);
    const { from, to } = linkData || {
      from: tr.selection.from,
      to: tr.selection.to,
    };
    // 

This causes two major issues:

1. Unhandled RangeError Crash: If the link is positioned at the very end of the document (position === tr.doc.content.size), position + 1 resolves beyond document bounds. Inside getLinkMarkAtPos, tr.doc.resolve(pos) throws an uncaught RangeError: Position out of range, causing the editor to crash.
2. Text Duplication & Delete Failure: When the cursor caret is resting at the end of a link (position === link.to), position + 1 queries the character after the link. Since that node lacks the link mark, getLinkMarkAtPos returns undefined and falls back to { from: tr.selection.from, to: tr.selection.to }. Because the selection is a collapsed caret (from === to), editLink inserts the new text beside the old text without replacing it (resulting in OriginalTextEditedText duplication), and deleteLink attempts tr.removeMark(from, to, link) over an empty 0-length range, completely failing to remove the link.

What did you expect to happen?

1. editLink and deleteLink should never throw an out-of-range error when the cursor is at the end of a document.
2. When the cursor is positioned at the boundary or end of a link (position === link.to), editLink should successfully replace the existing link text rather than duplicating it, and deleteLink should cleanly remove the link mark.

Steps to reproduce

Scenario A: RangeError Crash

1. Create a document where a link is the last element: GitHub
2. Place the cursor at the end of the document (position === editor.prosemirrorState.doc.content.size).
3. Trigger editor.editLink("https://github.com", "GitHub Homepage") or editor.deleteLink().
4. Observed: Uncaught RangeError: Position out of range thrown from tr.doc.resolve(pos).

Scenario B: Text Duplication / Failed Deletion

1. Type a link: Google and place the cursor at the end of the text (position === link.to).
2. Call editor.editLink("https://google.com", "Google Search").
3. Observed: The text becomes GoogleGoogle Search instead of Google Search.
4. Call editor.deleteLink() with the cursor at the same position.
5. Observed: The link remains active and is not deleted.

BlockNote version

Version: 0.54.0 (and main branch) Package: @blocknote/core

Environment

OS: Any (Windows / macOS / Linux) Browsers: Chrome, Firefox, Safari, Edge Frameworks: Vanilla JS, React, Vue

Additional context

Root Cause

getLinkMarkAtPos expects a valid in-bounds position. Unconditionally adding + 1 breaks on right-boundary cursor positions and document ends.

Proposed Fix

1. Guard getLinkMarkAtPos against positions exceeding tr.doc.content.size.
2. Inspect position directly, falling back to position - 1 if the cursor is at the trailing boundary of the link:

--- a/packages/core/src/editor/managers/StyleManager.ts
+++ b/packages/core/src/editor/managers/StyleManager.ts
@@ -154,6 +154,10 @@ export class StyleManager {
     return this.editor.transact((tr) => {
+      const clampedPos = Math.min(Math.max(0, pos), tr.doc.content.size);
+      const resolvedPos = tr.doc.resolve(clampedPos);
       const linkMark = resolvedPos
         .marks()
         .find((mark) => mark.type.name === "link");
@@ -224,7 +228,8 @@ export class StyleManager {
     this.editor.transact((tr) => {
-      const linkData = this.getLinkMarkAtPos(position + 1);
+      const linkData =
+        this.getLinkMarkAtPos(position) ||
+        (position > 0 ? this.getLinkMarkAtPos(position - 1) : undefined);
       const { from, to } = linkData || {
         from: tr.selection.from,
         to: tr.selection.to,
       };
@@ -248,7 +253,8 @@ export class StyleManager {
     this.editor.transact((tr) => {
-      const linkData = this.getLinkMarkAtPos(position + 1);
+      const linkData =
+        this.getLinkMarkAtPos(position) ||
+        (position > 0 ? this.getLinkMarkAtPos(position - 1) : undefined);
       const { from, to } = linkData || {
         from: tr.selection.from,
         to: tr.selection.to,

Contribution

• I'd be interested in contributing a fix for this issue

Sponsor

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Start in packages/core/src/editor/managers/StyleManager.ts, focusing on getLinkMarkAtPos, editLink, and deleteLink around the referenced lines. Reproduce both end-of-document and trailing-link cases, then verify that boundary positions do not throw, editing replaces the link text without duplication, and deletion removes the link mark.