Fix an issue where same-site references across spaces created invalid links. (#3407)

Author: emmerich

packages/gitbook/src/lib/links.test.ts

@@ -114,4 +114,27 @@ describe('linkerWithOtherSpaceBasePath', () => {
             '/section/variant/some/path'
         );
     });
+
+    it('should return a new linker that resolves links relative to a new spaceBasePath in the current site', () => {
+        const otherSpaceBasePathLinker = linkerWithOtherSpaceBasePath(root, {
+            spaceBasePath: '/section/variant',
+        });
+        expect(otherSpaceBasePathLinker.toPathInSpace('some/path')).toBe(
+            '/section/variant/some/path'
+        );
+    });
+
+    it('should use a basepath relative to the site', () => {
+        const otherSpaceBasePathLinker = linkerWithOtherSpaceBasePath(siteGitBookIO, {
+            spaceBasePath: 'a/b',
+        });
+        expect(otherSpaceBasePathLinker.toPathInSpace('some/path')).toBe('/sitename/a/b/some/path');
+    });
+
+    it('should use a basepath relative to the site (with trailing slash)', () => {
+        const otherSpaceBasePathLinker = linkerWithOtherSpaceBasePath(siteGitBookIO, {
+            spaceBasePath: '/a/b',
+        });
+        expect(otherSpaceBasePathLinker.toPathInSpace('some/path')).toBe('/sitename/a/b/some/path');
+    });
 });

packages/gitbook/src/lib/links.ts

@@ -142,13 +142,22 @@ export function linkerWithAbsoluteURLs(linker: GitBookLinker): GitBookLinker {
  */
 export function linkerWithOtherSpaceBasePath(
     linker: GitBookLinker,
-    { spaceBasePath }: { spaceBasePath: string }
+    {
+        spaceBasePath,
+    }: {
+        /**
+         * The base path of the space. It should be relative to the root of the site.
+         */
+        spaceBasePath: string;
+    }
 ): GitBookLinker {
     const newLinker: GitBookLinker = {
         ...linker,
         toPathInSpace(relativePath: string): string {
-            return joinPaths(spaceBasePath, relativePath);
+            return linker.toPathInSite(joinPaths(spaceBasePath, relativePath));
         },
+        // implementation matches the base linker toPathForPage, but decouples from using `this` to
+        // ensure we always use the updates `toPathInSpace` method.
         toPathForPage({ pages, page, anchor }) {
             return newLinker.toPathInSpace(getPagePath(pages, page)) + (anchor ? `#${anchor}` : '');
         },