fix(mobile): Windows image paths and non-ASCII file links open like desktop (#25802)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: amv146 <39172404+amv146@users.noreply.github.com>

Author: 3 people

apps/mobile/src/lib/markdownDocument.ts

@@ -1,7 +1,8 @@
 import type { Root, RootContent } from "mdast";
-import { unified } from "unified";
+import { unified, type Processor } from "unified";
 import remarkParse from "remark-parse";
 import remarkGfm from "remark-gfm";
+import { isWindowsAbsolutePath } from "@t3tools/shared/path";
 
 const parser = unified().use(remarkParse).use(remarkGfm);
 export type MarkdownNode = Root | RootContent;
@@ -382,13 +383,62 @@ export function markdownWithTableBreaks(markdown: string): string {
   return transformNativeMarkdown(markdown, undefined, true);
 }
 
+// `>` covers a destination continued on a blockquote line.
+const WINDOWS_DESTINATION = /\](?:\(|:)[\s>]*<?(?:[A-Za-z]:[\\/]|\\\\)/;
+
+interface DestinationToken {
+  readonly start: { readonly offset: number };
+  readonly end: { readonly offset: number };
+}
+
+/**
+ * Markdown reads `C:\work\.t3` as `C:\work.t3`. Web keeps authored Windows destinations
+ * literally (see `remarkKeepWindowsPaths` in shared), so escape their backslashes to give
+ * both parsers here the same path. `\&` stays an escape, as `markdownWithHtml` emits it.
+ * Expects authored Markdown: already escaped output would be escaped twice.
+ */
+function markdownWithWindowsPathDestinations(markdown: string): string {
+  // Skips the extra parse for the common message that has no Windows destination.
+  if (!WINDOWS_DESTINATION.test(markdown)) return markdown;
+  const edits: MarkdownEdit[] = [];
+  function record(
+    this: { resume(): string; sliceSerialize(token: DestinationToken): string },
+    token: DestinationToken,
+  ) {
+    this.resume();
+    const authored = this.sliceSerialize(token);
+    if (!isWindowsAbsolutePath(authored) || !authored.includes("\\") || /[<>]/.test(authored))
+      return;
+    const start = token.start.offset;
+    const end = token.end.offset;
+    const escaped = authored.replace(/\\(?!&)/g, "\\\\");
+    // A bare destination ends at an unescaped `)`, so wrap it to keep `\)` inside.
+    const angled = markdown[start - 1] === "<";
+    edits.push({ start, end, content: angled ? escaped : `<${escaped}>` });
+  }
+  unified()
+    .use(remarkParse)
+    .use(remarkGfm)
+    .use(function (this: Processor) {
+      (this.data().fromMarkdownExtensions ??= []).push({
+        exit: { resourceDestinationString: record, definitionDestinationString: record },
+      });
+    })
+    .parse(markdown);
+  return applyMarkdownEdits(markdown, edits);
+}
+
+// HTML wrappers can expose Markdown that wasn't in the first AST, so normalize them first.
+export function markdownForNativeParsing(markdown: string): string {
+  return markdownWithWindowsPathDestinations(markdownWithHtml(markdown));
+}
+
 export function parseMarkdownDocument(markdown: string): Root {
-  return parser.parse(markdownWithHtml(markdown));
+  return parser.parse(markdownForNativeParsing(markdown));
 }
 
 export function markdownForNativeRendering(markdown: string, fileLink: RegExp): string {
-  // HTML wrappers can expose Markdown that wasn't in the first AST, so normalize them first.
-  return transformNativeMarkdown(markdownWithHtml(markdown), fileLink, true);
+  return transformNativeMarkdown(markdownForNativeParsing(markdown), fileLink, true);
 }
 
 /** Native media slots only cover standalone images; nested file embeds must become links. */

apps/mobile/src/lib/markdownHtml.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, it } from "vite-plus/test";
 import {
+  markdownForNativeRendering,
   markdownHtmlContent,
   markdownWithHtml,
   markdownWithFileEmbeds,
@@ -9,6 +10,7 @@ import {
 import { markdownImageSources } from "./markdownImageSources";
 import { markdownFileEmbedLabel, resolveMarkdownMediaPreview } from "./markdownMedia";
 import { resolveMarkdownLinkPresentation } from "./markdownLinks";
+import { ENRICHED_INLINE_FILE_LINK_REGEX } from "./enrichedLinkPresentation";
 import { EnvironmentId, ThreadId } from "@t3tools/contracts";
 import { parseMarkdown } from "react-native-enriched-markdown/src/web/parseMarkdown";
 
@@ -296,3 +298,35 @@ describe("file embeds in native thread and file Markdown", () => {
     expect(converted.fileHrefs.has(href)).toBe(true);
   });
 });
+
+describe("Windows paths in native Markdown", () => {
+  // regression: #23722 Markdown escapes ate the separator before `.t3` and `_build`
+  it("keeps backslashes in Windows image and link destinations", async () => {
+    const image = String.raw`C:\work\.t3\_build\shot.png`;
+    const link = String.raw`\\server\share\.t3\notes.md`;
+    const markdown = [
+      `![shot](${image} "Shot")`,
+      String.raw`![paren](C:\a\)b.png)`,
+      `[notes](<${link}>)`,
+      `<img src="${image}">`,
+      String.raw`![amp](C:\R&D\.t3\a&amp;b.png)`,
+      String.raw`<img src="C:\R&amp;D\.t3\b.png">`,
+      "> ![quoted](\n> " + image + ")",
+    ].join("\n\n");
+
+    const native = await parseMarkdown(
+      markdownForNativeRendering(markdown, ENRICHED_INLINE_FILE_LINK_REGEX),
+    );
+    const urls: string[] = [];
+    const collect = (node: { attributes?: { url?: string }; children?: unknown[] }) => {
+      if (node.attributes?.url) urls.push(node.attributes.url);
+      node.children?.forEach((child) => collect(child as typeof node));
+    };
+    collect(native);
+    const paren = String.raw`C:\a\)b.png`;
+    const amp = String.raw`C:\R&D\.t3\a&b.png`;
+    const htmlAmp = String.raw`C:\R&D\.t3\b.png`;
+    expect(urls).toEqual([image, paren, link, image, amp, htmlAmp, image]);
+    expect(markdownImageSources(markdown)).toEqual([image, paren, amp, htmlAmp]);
+  });
+});

apps/mobile/src/lib/markdownInlineFileLinks.test.ts

@@ -7,7 +7,6 @@ import { ENRICHED_INLINE_FILE_LINK_REGEX } from "./enrichedLinkPresentation";
 import {
   markdownForNativeRendering,
   markdownWithInlineFileLinks,
-  parseMarkdownDocument,
   markdownWithHtml,
 } from "./markdownDocument";
 
@@ -87,7 +86,7 @@ describe("inline code that names a file", () => {
 
   it("links to the exact path when it holds backslashes or ampersands", () => {
     for (const path of ["C:\\repo\\_private\\file.ts", "./src/a©.ts", "./src/[id].ts"]) {
-      const paragraph = parseMarkdownDocument(rewrite(`\`${path}\``)).children[0];
+      const paragraph = parser.parse(rewrite(`\`${path}\``)).children[0];
       const link = paragraph?.type === "paragraph" ? paragraph.children[0] : undefined;
       expect(link?.type === "link" && link.url).toBe(path);
       expect(

apps/mobile/src/lib/markdownLinks.ts

@@ -265,11 +265,7 @@ export function resolveMarkdownLinkPresentation(href: string): MarkdownLinkPrese
     }
   } catch {}
 
-  const target =
-    parseMarkdownFileLink(normalized) ??
-    (/^(?:[A-Za-z0-9._-]+(?: +[A-Za-z0-9._-]+)*\/)+$/.test(normalized)
-      ? { path: normalized }
-      : null);
+  const target = parseMarkdownFileLink(normalized);
   if (target) {
     return {
       kind: "file",

apps/mobile/src/native/EnrichedMarkdownText.tsx

@@ -7,7 +7,7 @@ import {
 import {
   markdownForNativeRendering,
   markdownWithFileEmbeds,
-  markdownWithHtml,
+  markdownForNativeParsing,
   markdownWithInlineFileLinks,
   markdownWithTableBreaks,
 } from "../lib/markdownDocument";
@@ -165,7 +165,7 @@ export function MobileEnrichedMarkdownText(props: SelectableMarkdownTextProps) {
       };
     }
     const content = markdownWithInlineFileLinks(
-      markdownWithHtml(props.markdown),
+      markdownForNativeParsing(props.markdown),
       ENRICHED_INLINE_FILE_LINK_REGEX,
     );
     const files = markdownWithFileEmbeds(content, fileEmbedLabel);

packages/shared/src/markdownLinks.test.ts

@@ -54,6 +54,15 @@ describe("parseMarkdownFileLink", () => {
     expect(parseMarkdownFileLink("docs/My%20Folder/")?.path).toBe("docs/My Folder/");
   });
 
+  // regression: #16096 relative links with non-ASCII names open as files
+  it("recognizes relative paths with non-ASCII names", () => {
+    expect(parseMarkdownFileLink("pastexam/線性代數/exam_易志偉.pdf")?.path).toBe(
+      "pastexam/線性代數/exam_易志偉.pdf",
+    );
+    expect(parseMarkdownFileLink("Résumé%20final.pdf")?.path).toBe("Résumé final.pdf");
+    expect(parseMarkdownFileLink("資料.備份")?.path).toBe("資料.備份");
+  });
+
   it("accepts conventional extensionless names with or without a position", () => {
     expect(parseMarkdownFileLink("Makefile")).toEqual({ path: "Makefile" });
     expect(parseMarkdownFileLink("Dockerfile:8")).toEqual({ path: "Dockerfile", line: 8 });

packages/shared/src/markdownLinks.ts

@@ -14,13 +14,14 @@ import {
 
 const RELATIVE_PATH_PREFIX_PATTERN = /^(~\/|\.{1,2}\/)/;
 
-// The final segment is optional so an explicit folder link may end in `/`
-// (`patches/`, `docs/My Folder/`). A bare name with no slash still fails.
+// Names may use any script (`線性代數/考試.pdf`). The final segment is optional so an
+// explicit folder link may end in `/` (`patches/`, `docs/My Folder/`). A bare name with no
+// slash still fails.
 const RELATIVE_FILE_PATH_PATTERN =
-  /^(?:[A-Za-z0-9._-]+(?: +[A-Za-z0-9._-]+)*\/)+(?:[A-Za-z0-9._-]+(?: +[A-Za-z0-9._-]+)*(?::\d+){0,2})?$/;
+  /^(?:[\p{L}\p{M}\p{N}._-]+(?: +[\p{L}\p{M}\p{N}._-]+)*\/)+(?:[\p{L}\p{M}\p{N}._-]+(?: +[\p{L}\p{M}\p{N}._-]+)*(?::\d+){0,2})?$/u;
 
 const RELATIVE_FILE_NAME_PATTERN =
-  /^[A-Za-z0-9._-]+(?: +[A-Za-z0-9._-]+)*\.[A-Za-z0-9_-]+(?::\d+){0,2}$/;
+  /^[\p{L}\p{M}\p{N}._-]+(?: +[\p{L}\p{M}\p{N}._-]+)*\.[\p{L}\p{M}\p{N}_-]+(?::\d+){0,2}$/u;
 
 const EXTERNAL_SCHEME_PATTERN = /^([A-Za-z][A-Za-z0-9+.-]*):(.*)$/;