Fix order of tags in text show rules matches (#5083)

3 files changed, 39 insertions, 20 deletions

diff --git a/crates/typst/src/realize.rs b/crates/typst/src/realize.rs
index 97c53ace..f999bfd4 100644
--- a/crates/typst/src/realize.rs
+++ b/crates/typst/src/realize.rs
@@ -1115,13 +1115,22 @@ fn visit_regex_match<'a>(
     elems: &[Pair<'a>],
     m: RegexMatch<'a>,
 ) -> SourceResult<()> {
-    let matched = m.offset..m.offset + m.text.len();
+    let match_range = m.offset..m.offset + m.text.len();
     let piece = TextElem::packed(m.text);
     let context = Context::new(None, Some(m.styles));
     let output = m.recipe.apply(s.engine, context.track(), piece)?;
 
-    let mut output = Some(output);
     let mut cursor = 0;
+    let mut output = Some(output);
+    let mut visit_unconsumed_match = |s: &mut State<'a, '_, '_, '_>| -> SourceResult<()> {
+        if let Some(output) = output.take() {
+            let revocation = Style::Revocation(m.id).into();
+            let outer = s.arenas.bump.alloc(m.styles);
+            let chained = outer.chain(s.arenas.styles.alloc(revocation));
+            visit(s, s.store(output), chained)?;
+        }
+        Ok(())
+    };
 
     for &(content, styles) in elems {
         // Just forward tags.
@@ -1130,48 +1139,49 @@ fn visit_regex_match<'a>(
             continue;
         }
 
-        // Determine the range of the element.
+        // At this point, we can have a `TextElem`, `SpaceElem`,
+        // `LinebreakElem`, or `SmartQuoteElem`. We now determine the range of
+        // the element.
         let len = content.to_packed::<TextElem>().map_or(1, |elem| elem.text.len());
-        let subrange = cursor..cursor + len;
+        let elem_range = cursor..cursor + len;
 
         // If the element starts before the start of match, visit it fully or
         // sliced.
-        if subrange.start < matched.start {
-            if subrange.end <= matched.start {
+        if elem_range.start < match_range.start {
+            if elem_range.end <= match_range.start {
                 visit(s, content, styles)?;
             } else {
                 let mut elem = content.to_packed::<TextElem>().unwrap().clone();
-                elem.text = elem.text[..matched.start - subrange.start].into();
+                elem.text = elem.text[..match_range.start - elem_range.start].into();
                 visit(s, s.store(elem.pack()), styles)?;
             }
         }
 
-        // When the match starts at or before this element ends, visit the
-        // match.
-        if matched.start <= subrange.end {
-            if let Some(output) = output.take() {
-                let revocation = Style::Revocation(m.id).into();
-                let outer = s.arenas.bump.alloc(m.styles);
-                let chained = outer.chain(s.arenas.styles.alloc(revocation));
-                visit(s, s.store(output), chained)?;
-            }
+        // When the match starts before this element ends, visit it.
+        if match_range.start < elem_range.end {
+            visit_unconsumed_match(s)?;
         }
 
         // If the element ends after the end of the match, visit if fully or
         // sliced.
-        if subrange.end > matched.end {
-            if subrange.start >= matched.end {
+        if elem_range.end > match_range.end {
+            if elem_range.start >= match_range.end {
                 visit(s, content, styles)?;
             } else {
                 let mut elem = content.to_packed::<TextElem>().unwrap().clone();
-                elem.text = elem.text[matched.end - subrange.start..].into();
+                elem.text = elem.text[match_range.end - elem_range.start..].into();
                 visit(s, s.store(elem.pack()), styles)?;
             }
         }
 
-        cursor = subrange.end;
+        cursor = elem_range.end;
     }
 
+    // If the match wasn't consumed yet, visit it. This shouldn't really happen
+    // in practice (we'd need to have an empty match at the end), but it's an
+    // extra fail-safe.
+    visit_unconsumed_match(s)?;
+
     Ok(())
 }
 
diff --git a/tests/ref/issue-5014-show-text-tags.png b/tests/ref/issue-5014-show-text-tags.png
new file mode 100644
index 00000000..4cefe9d3
--- /dev/null
+++ b/tests/ref/issue-5014-show-text-tags.png
diff --git a/tests/suite/styling/show-text.typ b/tests/suite/styling/show-text.typ
index 66ae6580..4e031648 100644
--- a/tests/suite/styling/show-text.typ
+++ b/tests/suite/styling/show-text.typ
@@ -199,3 +199,12 @@ $a^2 + b^2 = c^2$ is Pythagoras' theorem.
 a \ #h(0pt, weak: true)
 b \ #h(0pt, weak: true)
 $x$ c $y$
+
+--- issue-5014-show-text-tags ---
+#{
+  let c = counter("c")
+  show "b": context c.get().first()
+  [a]
+  c.step()
+  [bc]
+}