feat: report spans for missing alt text and unknown/duplicate tag ids

Cargo.lock

@@ -1373,7 +1373,7 @@ dependencies = [
 [[package]]
 name = "krilla"
 version = "0.4.0"
-source = "git+https://github.com/LaurenzV/krilla?branch=main#d40f81a01ca8f8654510a76effeef12518437800"
+source = "git+https://github.com/LaurenzV/krilla?branch=main#32d070e737cd8ae4c3aa4ff901d15cb22bd052f3"
 dependencies = [
  "base64",
  "bumpalo",
@@ -1402,7 +1402,7 @@ dependencies = [
 [[package]]
 name = "krilla-svg"
 version = "0.1.0"
-source = "git+https://github.com/LaurenzV/krilla?branch=main#d40f81a01ca8f8654510a76effeef12518437800"
+source = "git+https://github.com/LaurenzV/krilla?branch=main#32d070e737cd8ae4c3aa4ff901d15cb22bd052f3"
 dependencies = [
  "flate2",
  "fontdb",

crates/typst-library/src/foundations/content/mod.rs

@@ -23,10 +23,10 @@ use serde::{Serialize, Serializer};
 use typst_syntax::Span;
 use typst_utils::singleton;
 
-use crate::diag::{SourceResult, StrResult};
+use crate::diag::{bail, SourceResult, StrResult};
 use crate::engine::Engine;
 use crate::foundations::{
-    func, repr, scope, ty, Context, Dict, IntoValue, Label, Property, Recipe,
+    func, repr, scope, ty, Args, Context, Dict, IntoValue, Label, Property, Recipe,
     RecipeIndex, Repr, Selector, Str, Style, StyleChain, Styles, Value,
 };
 use crate::introspection::{Locatable, Location};
@@ -479,7 +479,7 @@ impl Content {
     /// Link the content somewhere.
     pub fn linked(self, dest: Destination, alt: Option<EcoString>) -> Self {
         let span = self.span();
-        LinkMarker::new(self, dest.clone(), alt)
+        LinkMarker::new(self, dest.clone(), alt, span)
             .pack()
             .spanned(span)
             .set(LinkElem::current, Some(dest))
@@ -785,15 +785,27 @@ impl Repr for StyledElem {
 }
 
 /// An element that associates the body of a link with the destination.
-#[elem(Locatable)]
+#[elem(Locatable, Construct)]
 pub struct LinkMarker {
     /// The content.
+    #[internal]
     #[required]
     pub body: Content,
+    #[internal]
     #[required]
     pub dest: Destination,
+    #[internal]
     #[required]
     pub alt: Option<EcoString>,
+    #[internal]
+    #[required]
+    pub span: Span,
+}
+
+impl Construct for LinkMarker {
+    fn construct(_: &mut Engine, args: &mut Args) -> SourceResult<Content> {
+        bail!(args.span, "cannot be constructed manually");
+    }
 }
 
 impl<T: NativeElement> IntoValue for T {

crates/typst-pdf/src/convert.rs

@@ -9,6 +9,7 @@ use krilla::error::KrillaError;
 use krilla::geom::PathBuilder;
 use krilla::page::{PageLabel, PageSettings};
 use krilla::surface::Surface;
+use krilla::tagging::TagId;
 use krilla::{Document, SerializeSettings};
 use krilla_svg::render_svg_glyph;
 use typst_library::diag::{bail, error, SourceDiagnostic, SourceResult};
@@ -373,11 +374,21 @@ fn finish(
                     .collect::<EcoVec<_>>();
                 Err(errors)
             }
-            KrillaError::DuplicateTagId(_, _) => {
+            KrillaError::DuplicateTagId(id, loc) => {
-                unreachable!("duplicate IDs shouldn't be generated")
+                let span = to_span(loc);
+                let id = display_tag_id(&id);
+                bail!(
+                    span, "duplicate tag id `{id}`";
+                    hint: "please report this as a bug"
+                )
             }
-            KrillaError::UnknownTagId(_, _) => {
+            KrillaError::UnknownTagId(id, loc) => {
-                unreachable!("all referenced IDs should be present in the tag tree")
+                let span = to_span(loc);
+                let id = display_tag_id(&id);
+                bail!(
+                    span, "unknown tag id `{id}`";
+                    hint: "please report this as a bug"
+                )
             }
             KrillaError::Image(_, loc) => {
                 let span = to_span(loc);
@@ -394,6 +405,20 @@ fn finish(
     }
 }
 
+fn display_tag_id(id: &TagId) -> impl std::fmt::Display + use<'_> {
+    typst_utils::display(|f| {
+        if let Ok(str) = std::str::from_utf8(id.as_bytes()) {
+            f.write_str(str)
+        } else {
+            f.write_str("0x")?;
+            for b in id.as_bytes() {
+                write!(f, "{b:x}")?;
+            }
+            Ok(())
+        }
+    })
+}
+
 /// Converts a krilla error into a Typst error.
 fn convert_error(
     gc: &GlobalContext,
@@ -562,16 +587,20 @@ fn convert_error(
         }
         // The below errors cannot occur yet, only once Typst supports full PDF/A
         // and PDF/UA. But let's still add a message just to be on the safe side.
-        ValidationError::MissingAnnotationAltText => error!(
+        ValidationError::MissingAnnotationAltText(loc) => {
-            Span::detached(),
+            let span = to_span(*loc);
-            "{prefix} missing annotation alt text";
+            error!(
-            hint: "please report this as a bug"
+                span, "{prefix} missing annotation alt text";
-        ),
+                hint: "please report this as a bug"
-        ValidationError::MissingAltText => error!(
+            )
-            Span::detached(),
+        }
-            "{prefix} missing alt text";
+        ValidationError::MissingAltText(loc) => {
-            hint: "make sure your images and equations have alt text"
+            let span = to_span(*loc);
-        ),
+            error!(
+                span, "{prefix} missing alt text";
+                hint: "make sure your images and equations have alt text"
+            )
+        }
         ValidationError::NoDocumentLanguage => error!(
             Span::detached(),
             "{prefix} missing document language";

crates/typst-pdf/src/link.rs

@@ -6,6 +6,7 @@ use krilla::destination::XyzDestination;
 use krilla::geom as kg;
 use typst_library::layout::{Point, Position, Size};
 use typst_library::model::Destination;
+use typst_syntax::Span;
 
 use crate::convert::{FrameContext, GlobalContext};
 use crate::tags::{self, Placeholder, TagNode};
@@ -17,6 +18,7 @@ pub(crate) struct LinkAnnotation {
     pub(crate) alt: Option<String>,
     pub(crate) quad_points: Vec<kg::Quadrilateral>,
     pub(crate) target: Target,
+    pub(crate) span: Span,
 }
 
 pub(crate) fn handle_link(
@@ -70,6 +72,7 @@ pub(crate) fn handle_link(
                 quad_points: vec![quad],
                 alt,
                 target,
+                span: link.span,
             });
         }
     }

crates/typst-pdf/src/tags/mod.rs

@@ -176,6 +176,7 @@ pub(crate) fn handle_start(
         return Ok(());
     };
 
+    let tag = tag.with_location(Some(elem.span().into_raw().get()));
     push_stack(gc, loc, StackEntryKind::Standard(tag))?;
 
     Ok(())
@@ -202,7 +203,8 @@ pub(crate) fn handle_end(gc: &mut GlobalContext, surface: &mut Surface, loc: Loc
                 // PDF/UA compliance of the structure hierarchy is checked
                 // elsewhere. While this doesn't make a lot of sense, just
                 // avoid crashing here.
-                let tag = TagKind::TOCI.into();
+                let tag = TagKind::TOCI
+                    .with_location(Some(outline_entry.span().into_raw().get()));
                 gc.tags.push(TagNode::Group(tag, entry.nodes));
                 return;
             };
@@ -216,7 +218,8 @@ pub(crate) fn handle_end(gc: &mut GlobalContext, surface: &mut Surface, loc: Loc
                 // PDF/UA compliance of the structure hierarchy is checked
                 // elsewhere. While this doesn't make a lot of sense, just
                 // avoid crashing here.
-                let tag = TagKind::TD(TableDataCell::new()).into();
+                let tag = TagKind::TD(TableDataCell::new())
+                    .with_location(Some(cell.span().into_raw().get()));
                 gc.tags.push(TagNode::Group(tag, entry.nodes));
                 return;
             };
@@ -324,11 +327,13 @@ pub(crate) fn add_annotations(
     annotations: Vec<LinkAnnotation>,
 ) {
     for annotation in annotations.into_iter() {
-        let LinkAnnotation { id: _, placeholder, alt, quad_points, target } = annotation;
+        let LinkAnnotation { id: _, placeholder, alt, quad_points, target, span } =
+            annotation;
         let annot = krilla::annotation::Annotation::new_link(
             krilla::annotation::LinkAnnotation::new_with_quad_points(quad_points, target),
             alt,
-        );
+        )
+        .with_location(Some(span.into_raw().get()));
         let annot_id = page.add_tagged_annotation(annot);
         gc.tags.placeholders.init(placeholder, Node::Leaf(annot_id));
     }

crates/typst-pdf/src/tags/table.rs

@@ -9,6 +9,7 @@ use smallvec::SmallVec;
 use typst_library::foundations::{Packed, Smart, StyleChain};
 use typst_library::model::TableCell;
 use typst_library::pdf::{TableCellKind, TableHeaderScope};
+use typst_syntax::Span;
 
 use crate::tags::{TableId, TagNode};
 
@@ -57,7 +58,7 @@ impl TableCtx {
         }
     }
 
-    pub(crate) fn insert(&mut self, cell: &TableCell, nodes: Vec<TagNode>) {
+    pub(crate) fn insert(&mut self, cell: &Packed<TableCell>, nodes: Vec<TagNode>) {
         let x = cell.x.get(StyleChain::default()).unwrap_or_else(|| unreachable!());
         let y = cell.y.get(StyleChain::default()).unwrap_or_else(|| unreachable!());
         let rowspan = cell.rowspan.get(StyleChain::default());
@@ -92,6 +93,7 @@ impl TableCtx {
             kind,
             headers: SmallVec::new(),
             nodes,
+            span: cell.span(),
         });
     }
 
@@ -175,13 +177,14 @@ impl TableCtx {
                                     .with_headers(cell.headers),
                             )
                             .with_id(Some(id))
+                            .with_location(Some(cell.span.into_raw().get()))
                         }
                         TableCellKind::Footer | TableCellKind::Data => TagKind::TD(
                             TableDataCell::new()
                                 .with_span(span)
                                 .with_headers(cell.headers),
                         )
-                        .into(),
+                        .with_location(Some(cell.span.into_raw().get())),
                     };
                     Some(TagNode::Group(tag, cell.nodes))
                 })
@@ -296,6 +299,7 @@ struct TableCtxCell {
     kind: Smart<TableCellKind>,
     headers: SmallVec<[TagId; 1]>,
     nodes: Vec<TagNode>,
+    span: Span,
 }
 
 impl TableCtxCell {
@@ -344,7 +348,7 @@ mod tests {
     fn table<const SIZE: usize>(cells: [TableCell; SIZE]) -> TableCtx {
         let mut table = TableCtx::new(TableId(324), Some("summary".into()));
         for cell in cells {
-            table.insert(&cell, Vec::new());
+            table.insert(&Packed::new(cell), Vec::new());
         }
         table
     }
@@ -416,7 +420,9 @@ mod tests {
         let id = table_cell_id(TableId(324), x, y);
         let ids = headers.map(|(x, y)| table_cell_id(TableId(324), x, y));
         TagNode::Group(
-            TagKind::TH(TableHeaderCell::new(scope).with_headers(ids)).with_id(Some(id)),
+            TagKind::TH(TableHeaderCell::new(scope).with_headers(ids))
+                .with_id(Some(id))
+                .with_location(Some(Span::detached().into_raw().get())),
             Vec::new(),
         )
     }
@@ -424,7 +430,8 @@ mod tests {
     fn td<const SIZE: usize>(headers: [(u32, u32); SIZE]) -> TagNode {
         let ids = headers.map(|(x, y)| table_cell_id(TableId(324), x, y));
         TagNode::Group(
-            TagKind::TD(TableDataCell::new().with_headers(ids)).into(),
+            TagKind::TD(TableDataCell::new().with_headers(ids))
+                .with_location(Some(Span::detached().into_raw().get())),
             Vec::new(),
         )
     }