From 3455ac7dd2f5c3cb8785692d45eac8dd4110ce79 Mon Sep 17 00:00:00 2001
From: "Y.D.X." <73375426+YDX-2147483647@users.noreply.github.com>
Date: Thu, 7 Aug 2025 19:17:54 +0800
Subject: [PATCH] Include numbering in PDF bookmark (#6622)

Co-authored-by: Laurenz <laurmaedje@gmail.com>
---
 crates/typst-library/src/model/heading.rs | 23 +++++++++++++++++++++++
 crates/typst-pdf/src/outline.rs           |  8 +++++++-
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/crates/typst-library/src/model/heading.rs b/crates/typst-library/src/model/heading.rs
index f5e7f4f37..d61aa415d 100644
--- a/crates/typst-library/src/model/heading.rs
+++ b/crates/typst-library/src/model/heading.rs
@@ -1,5 +1,6 @@
 use std::num::NonZeroUsize;
 
+use ecow::EcoString;
 use typst_utils::NonZeroExt;
 
 use crate::diag::SourceResult;
@@ -103,6 +104,18 @@ pub struct HeadingElem {
     /// ```
     pub numbering: Option<Numbering>,
 
+    /// The resolved plain-text numbers.
+    ///
+    /// This field is internal and only used for creating PDF bookmarks. We
+    /// don't currently have access to `World`, `Engine`, or `styles` in export,
+    /// which is needed to resolve the counter and numbering pattern into a
+    /// concrete string.
+    ///
+    /// This remains unset if `numbering` is `None`.
+    #[internal]
+    #[synthesized]
+    pub numbers: EcoString,
+
     /// A supplement for the heading.
     ///
     /// For references to headings, this is added before the referenced number.
@@ -202,6 +215,16 @@ impl Synthesize for Packed<HeadingElem> {
             }
         };
 
+        if let Some((numbering, location)) =
+            self.numbering.get_ref(styles).as_ref().zip(self.location())
+        {
+            self.numbers = Some(
+                self.counter()
+                    .display_at_loc(engine, location, styles, numbering)?
+                    .plain_text(),
+            );
+        }
+
         let elem = self.as_mut();
         elem.level.set(Smart::Custom(elem.resolve_level(styles)));
         elem.supplement
diff --git a/crates/typst-pdf/src/outline.rs b/crates/typst-pdf/src/outline.rs
index 7228f0f32..dc9216e20 100644
--- a/crates/typst-pdf/src/outline.rs
+++ b/crates/typst-pdf/src/outline.rs
@@ -124,10 +124,16 @@ impl<'a> HeadingNode<'a> {
 
     fn to_krilla(&self, gc: &GlobalContext) -> Option<OutlineNode> {
         let loc = self.element.location().unwrap();
-        let title = self.element.body.plain_text().to_string();
         let pos = gc.document.introspector.position(loc);
         let page_index = pos.page.get() - 1;
 
+        // Prepend the numbers to the title if they exist.
+        let text = self.element.body.plain_text();
+        let title = match &self.element.numbers {
+            Some(num) => format!("{num} {text}"),
+            None => text.to_string(),
+        };
+
         if let Some(index) = gc.page_index_converter.pdf_page_index(page_index) {
             let y = (pos.point.y - Abs::pt(10.0)).max(Abs::zero());
             let dest = XyzDestination::new(