Fix matrix.to links with custom text being sent as escaped html

src/app/components/editor/output.test.ts

@@ -28,3 +28,52 @@ describe('toMatrixCustomHTML emoticons', () => {
     expect(html).toContain('height="32"');
   });
 });
+
+describe('toMatrixCustomHTML matrix.to', () => {
+  it('serializes room mentions as raw matrix.to URL text, not an anchor', () => {
+    const html = trimCustomHtml(
+      toMatrixCustomHTML(
+        [
+          {
+            type: BlockType.Paragraph,
+            children: [
+              {
+                type: BlockType.Mention,
+                id: '!room:example.org',
+                name: 'My room',
+                children: [{ text: '' }],
+              } as never,
+            ],
+          } as never,
+        ],
+        {}
+      )
+    );
+
+    expect(html).toContain('https://matrix.to/#/!room:example.org');
+    expect(html).not.toMatch(/<a\b[^>]*matrix\.to/i);
+  });
+
+  it('serializes matrix.to links as raw URL text, not an anchor', () => {
+    const html = trimCustomHtml(
+      toMatrixCustomHTML(
+        [
+          {
+            type: BlockType.Paragraph,
+            children: [
+              {
+                type: BlockType.Link,
+                href: 'https://matrix.to/#/@alice:example.org',
+                children: [{ text: 'Alice' }],
+              } as never,
+            ],
+          } as never,
+        ],
+        {}
+      )
+    );
+
+    expect(html).toContain('https://matrix.to/#/@alice:example.org');
+    expect(html).not.toMatch(/<a\b[^>]*matrix\.to/i);
+  });
+});

src/app/components/editor/output.ts

@@ -8,7 +8,7 @@ import { isUserId } from '$utils/matrix';
 import type { CustomElement } from './slate';
 import { BlockType } from './types';
 import { getMarkdownCodeSpanRanges, isInsideMarkdownCodeSpan } from './utils';
-import { MATRIX_TO_BASE } from '$plugins/matrix-to';
+import { MATRIX_TO_BASE, testMatrixTo } from '$plugins/matrix-to';
 
 export type OutputOptions = {
   /**
@@ -38,8 +38,8 @@ const elementToCustomHtml = (node: CustomElement, children: string): string => {
         fragment += `?${node.viaServers.map((server) => `via=${server}`).join('&')}`;
       }
 
-      const matrixTo = `https://matrix.to/#/${fragment}`;
-      return `<a href="${encodeURI(matrixTo)}" target="_blank" rel="noreferrer noopener">${sanitizeText(node.name)}</a>`;
+      const matrixTo = `${MATRIX_TO_BASE}#/${fragment}`;
+      return sanitizeText(matrixTo);
     }
     case BlockType.Emoticon:
       return node.key.startsWith('mxc://')
@@ -48,7 +48,9 @@ const elementToCustomHtml = (node: CustomElement, children: string): string => {
           )}" title="${sanitizeText(node.shortcode)}" height="32" />`
         : sanitizeText(node.key);
     case BlockType.Link:
-      return `<a href="${encodeURI(node.href)}" target="_blank" rel="noreferrer noopener">${children}</a>`;
+      return testMatrixTo(node.href)
+        ? sanitizeText(node.href)
+        : `<a href="${encodeURI(node.href)}" target="_blank" rel="noreferrer noopener">${children}</a>`;
     case BlockType.Command:
       return `/${sanitizeText(node.command)}`;
     default:

src/app/plugins/markdown/markdownToHtml.test.ts

@@ -223,4 +223,21 @@ describe('markdownToHtml', () => {
     const result = markdownToHtml(html);
     expect(result).not.toContain('?');
   });
+
+  it('keeps normal markdown links valid when many bare matrix.to URLs are shielded', () => {
+    const matrixLines = Array.from(
+      { length: 12 },
+      (_, i) => `https://matrix.to/#/@u${i}:example.org`
+    ).join('\n');
+    const md = `${matrixLines}\n[docs](https://example.com/doc)`;
+    const result = markdownToHtml(md);
+    expect(result).toContain('<a href="https://example.com/doc"');
+    expect(result).not.toContain('&lt;a href=');
+  });
+
+  it('emits bare matrix.to text for unformatted URLs, not anchor tags', () => {
+    const result = markdownToHtml('join https://matrix.to/#/#room:example.org please');
+    expect(result).toContain('https://matrix.to/#/#room:example.org');
+    expect(result).not.toMatch(/<a[^>]*matrix\.to/);
+  });
 });

src/app/plugins/markdown/markdownToHtml.ts

@@ -77,8 +77,10 @@
 
 const unshieldBareMatrixToLinks = (html: string, placeholders: Map<string, string>): string => {
   let result = html;
-  for (const [key, url] of placeholders.entries()) {
-    result = result.split(key).join(escapeHtml(url));
+  const keys = [...placeholders.keys()].sort((a, b) => b.length - a.length);
+  for (const key of keys) {
+    const url = placeholders.get(key);
+    if (url) result = result.split(key).join(escapeHtml(url));
   }
   return result;
 };