Delay errors for all show rules (#3323)

crates/typst/src/introspection/counter.rs

@@ -635,7 +635,6 @@ struct DisplayElem {
 impl Show for Packed<DisplayElem> {
     #[typst_macros::time(name = "counter.display", span = self.span())]
     fn show(&self, engine: &mut Engine, styles: StyleChain) -> SourceResult<Content> {
-        Ok(engine.delayed(|engine| {
         let location = self.location().unwrap();
         let counter = self.counter();
         let numbering = self
@@ -665,7 +664,6 @@ impl Show for Packed<DisplayElem> {
         };
 
         state.display(engine, &numbering)
-        }))
     }
 }
 

crates/typst/src/introspection/locate.rs

@@ -44,9 +44,7 @@ struct LocateElem {
 impl Show for Packed<LocateElem> {
     #[typst_macros::time(name = "locate", span = self.span())]
     fn show(&self, engine: &mut Engine, _: StyleChain) -> SourceResult<Content> {
-        Ok(engine.delayed(|engine| {
         let location = self.location().unwrap();
         Ok(self.func().call(engine, [location])?.display())
-        }))
     }
 }

crates/typst/src/introspection/state.rs

@@ -388,14 +388,12 @@ struct DisplayElem {
 impl Show for Packed<DisplayElem> {
     #[typst_macros::time(name = "state.display", span = self.span())]
     fn show(&self, engine: &mut Engine, _: StyleChain) -> SourceResult<Content> {
-        Ok(engine.delayed(|engine| {
         let location = self.location().unwrap();
         let value = self.state().at(engine, location)?;
         Ok(match self.func() {
             Some(func) => func.call(engine, [value])?.display(),
             None => value.display(),
         })
-        }))
     }
 }
 

crates/typst/src/model/bibliography.rs

@@ -225,7 +225,6 @@ impl Show for Packed<BibliographyElem> {
             );
         }
 
-        Ok(engine.delayed(|engine| {
         let span = self.span();
         let works = Works::generate(engine.world, engine.introspector).at(span)?;
         let references = works
@@ -242,9 +241,7 @@ impl Show for Packed<BibliographyElem> {
                     Packed::new(GridCell::new(prefix.clone().unwrap_or_default()))
                         .spanned(span),
                 );
-                    cells.push(
-                        Packed::new(GridCell::new(reference.clone())).spanned(span),
-                    );
+                cells.push(Packed::new(GridCell::new(reference.clone())).spanned(span));
             }
 
             seq.push(VElem::new(row_gutter).with_weakness(3).pack());
@@ -269,7 +266,6 @@ impl Show for Packed<BibliographyElem> {
         }
 
         Ok(content)
-        }))
     }
 }
 

crates/typst/src/model/cite.rs

@@ -152,7 +152,6 @@ pub struct CiteGroup {
 impl Show for Packed<CiteGroup> {
     #[typst_macros::time(name = "cite", span = self.span())]
     fn show(&self, engine: &mut Engine, _: StyleChain) -> SourceResult<Content> {
-        Ok(engine.delayed(|engine| {
         let location = self.location().unwrap();
         let span = self.span();
         Works::generate(engine.world, engine.introspector)
@@ -160,9 +159,6 @@ impl Show for Packed<CiteGroup> {
             .citations
             .get(&location)
             .cloned()
-                .unwrap_or_else(|| {
-                    bail!(span, "failed to format citation (this is a bug)")
-                })
-        }))
+            .unwrap_or_else(|| bail!(span, "failed to format citation (this is a bug)"))
     }
 }

crates/typst/src/model/footnote.rs

@@ -126,7 +126,6 @@ impl Packed<FootnoteElem> {
 impl Show for Packed<FootnoteElem> {
     #[typst_macros::time(name = "footnote", span = self.span())]
     fn show(&self, engine: &mut Engine, styles: StyleChain) -> SourceResult<Content> {
-        Ok(engine.delayed(|engine| {
         let loc = self.declaration_location(engine).at(self.span())?;
         let numbering = self.numbering(styles);
         let counter = Counter::of(FootnoteElem::elem());
@@ -135,7 +134,6 @@ impl Show for Packed<FootnoteElem> {
         let loc = loc.variant(1);
         // Add zero-width weak spacing to make the footnote "sticky".
         Ok(HElem::hole().pack() + sup.linked(Destination::Location(loc)))
-        }))
     }
 }
 

crates/typst/src/model/link.rs

@@ -95,13 +95,11 @@ impl Show for Packed<LinkElem> {
         let body = self.body().clone();
         let linked = match self.dest() {
             LinkTarget::Dest(dest) => body.linked(dest.clone()),
-            LinkTarget::Label(label) => engine
-                .delayed(|engine| {
+            LinkTarget::Label(label) => {
                 let elem = engine.introspector.query_label(*label).at(self.span())?;
                 let dest = Destination::Location(elem.location().unwrap());
-                    Ok(Some(body.clone().linked(dest)))
-                })
-                .unwrap_or(body),
+                body.clone().linked(dest)
+            }
         };
 
         Ok(linked.styled(TextElem::set_hyphenate(Hyphenate(Smart::Custom(false)))))

crates/typst/src/model/reference.rs

@@ -163,7 +163,6 @@ impl Synthesize for Packed<RefElem> {
 impl Show for Packed<RefElem> {
     #[typst_macros::time(name = "ref", span = self.span())]
     fn show(&self, engine: &mut Engine, styles: StyleChain) -> SourceResult<Content> {
-        Ok(engine.delayed(|engine| {
         let target = *self.target();
         let elem = engine.introspector.query_label(target);
         let span = self.span();
@@ -200,10 +199,7 @@ impl Show for Packed<RefElem> {
         let numbering = refable
             .numbering()
             .ok_or_else(|| {
-                    eco_format!(
-                        "cannot reference {} without numbering",
-                        elem.func().name()
-                    )
+                eco_format!("cannot reference {} without numbering", elem.func().name())
             })
             .hint(eco_format!(
                 "you can enable {} numbering with `#set {}(numbering: \"1.\")`",
@@ -234,7 +230,6 @@ impl Show for Packed<RefElem> {
         }
 
         Ok(content.linked(Destination::Location(loc)))
-        }))
     }
 }
 

crates/typst/src/realize/mod.rs

@@ -92,18 +92,17 @@ pub fn realize(
         meta = prepare(engine, &mut target, &mut map, styles)?;
     }
 
-    // Apply the step.
+    // Apply a step, if there is one.
     let mut output = match step {
-        // Apply a user-defined show rule.
-        Some(Step::Recipe(recipe, guard)) => show(engine, target, recipe, guard)?,
-
-        // If the verdict picks this step, the `target` is guaranteed
-        // to have a built-in show rule.
-        Some(Step::Builtin) => {
-            target.with::<dyn Show>().unwrap().show(engine, styles.chain(&map))?
+        Some(step) => {
+            // Errors in show rules don't terminate compilation immediately. We
+            // just continue with empty content for them and show all errors
+            // together, if they remain by the end of the introspection loop.
+            //
+            // This way, we can ignore errors that only occur in earlier
+            // iterations and also show more useful errors at once.
+            engine.delayed(|engine| show(engine, target, step, styles.chain(&map)))
         }
-
-        // Nothing to do.
         None => target,
     };
 
@@ -122,12 +121,12 @@ struct Verdict<'a> {
     prepared: bool,
     /// A map of styles to apply to the element.
     map: Styles,
-    /// An optional transformation step to apply to the element.
-    step: Option<Step<'a>>,
+    /// An optional show rule transformation to apply to the element.
+    step: Option<ShowStep<'a>>,
 }
 
-/// An optional transformation step to apply to an element.
-enum Step<'a> {
+/// An optional show rule transformation to apply to the element.
+enum ShowStep<'a> {
     /// A user-defined transformational show rule.
     Recipe(&'a Recipe, RecipeIndex),
     /// The built-in show rule.
@@ -200,7 +199,7 @@ fn verdict<'a>(
                 // If we find a matching, unguarded replacement show rule,
                 // remember it, but still continue searching for potential
                 // show-set styles that might change the verdict.
-                step = Some(Step::Recipe(recipe, index));
+                step = Some(ShowStep::Recipe(recipe, index));
 
                 // If we found a show rule and are already prepared, there is
                 // nothing else to do, so we can just break.
@@ -215,7 +214,7 @@ fn verdict<'a>(
 
     // If we found no user-defined rule, also consider the built-in show rule.
     if step.is_none() && target.can::<dyn Show>() {
-        step = Some(Step::Builtin);
+        step = Some(ShowStep::Builtin);
     }
 
     // If there's no nothing to do, there is also no verdict.
@@ -286,21 +285,30 @@ fn prepare(
     Ok(None)
 }
 
-/// Apply a user-defined show rule.
+/// Apply a step.
 fn show(
     engine: &mut Engine,
     target: Content,
-    recipe: &Recipe,
-    index: RecipeIndex,
+    step: ShowStep,
+    styles: StyleChain,
 ) -> SourceResult<Content> {
-    match &recipe.selector {
+    match step {
+        // Apply a user-defined show rule.
+        ShowStep::Recipe(recipe, guard) => match &recipe.selector {
+            // If the selector is a regex, the `target` is guaranteed to be a
+            // text element. This invokes special regex handling.
             Some(Selector::Regex(regex)) => {
-            // If the verdict picks this rule, the `target` is guaranteed
-            // to be a text element.
                 let text = target.into_packed::<TextElem>().unwrap();
-            show_regex(engine, &text, regex, recipe, index)
+                show_regex(engine, &text, regex, recipe, guard)
             }
-        _ => recipe.apply(engine, target.guarded(index)),
+
+            // Just apply the recipe.
+            _ => recipe.apply(engine, target.guarded(guard)),
+        },
+
+        // If the verdict picks this step, the `target` is guaranteed to have a
+        // built-in show rule.
+        ShowStep::Builtin => target.with::<dyn Show>().unwrap().show(engine, styles),
     }
 }
 

tests/typ/compiler/delayed-error.typ

@@ -0,0 +1,11 @@
+// Test that errors in show rules are delayed: There can be multiple at once.
+
+---
+// Error: 26-34 panicked with: "hey1"
+#show heading: _ => panic("hey1")
+
+// Error: 25-33 panicked with: "hey2"
+#show strong: _ => panic("hey2")
+
+= Hello
+*strong*