Add isSpaceInSiteStructure function and update resolveContentRef logic for cross-space references

packages/gitbook/src/lib/references.tsx

@@ -29,7 +29,12 @@ import { PageIcon } from '@/components/PageIcon';
 import { getGitBookAppHref } from './app';
 import { getBlockById, getBlockTitle } from './document';
 import { resolvePageId } from './pages';
-import { findSiteSpaceBy, getFallbackSiteSpacePath, getLocalizedTitle } from './sites';
+import {
+    findSiteSpaceBy,
+    getFallbackSiteSpacePath,
+    getLocalizedTitle,
+    isSpaceInSiteStructure,
+} from './sites';
 import { getRevisionTags, resolveTag } from './tags';
 import type { ClassValue } from './tailwind';
 import { filterOutNullable } from './typescript';
@@ -163,6 +168,14 @@ export async function resolveContentRef(
         case 'anchor':
         case 'page': {
             if (isContentRefInDifferentSpace(contentRef, context)) {
+                // Only resolve cross-space page/anchor refs when the target space
+                // is part of the current site's structure.
+                if (
+                    'site' in context &&
+                    !isSpaceInSiteStructure(context.structure, contentRef.space)
+                ) {
+                    return null;
+                }
                 return resolveContentRefInSpace(contentRef.space, context, contentRef, options);
             }
 

packages/gitbook/src/lib/sites.ts

@@ -57,6 +57,14 @@ export function listAllSiteSpaces(siteStructure: SiteStructure) {
     });
 }
 
+/**
+ * Check if a space is part of a site structure by scanning every site section
+ * and all the siteSpaces associated with each section.
+ */
+export function isSpaceInSiteStructure(siteStructure: SiteStructure, spaceId: string): boolean {
+    return !!findSiteSpaceBy(siteStructure, (siteSpace) => siteSpace.space.id === spaceId);
+}
+
 /**
  * Find a site space by its spaceId in a site structure.
  */