only flush orphans outside of headers and footers

crates/typst-layout/src/grid/layouter.rs

@@ -66,6 +66,16 @@ pub struct GridLayouter<'a> {
     /// calculation.
     /// TODO: consider refactoring this into something nicer.
     pub(super) current_row_height: Option<Abs>,
+    /// This is `true` when laying out non-short lived headers and footers.
+    /// That is, headers and footers which are not immediately followed or
+    /// preceded (respectively) by conflicting headers and footers of same or
+    /// lower level, or the end or start of the table (respectively), which
+    /// would cause them to stop repeating.
+    ///
+    /// If this is `false`, the next row to be laid out will remove an active
+    /// orphan snapshot and will flush pending headers, as there is no risk
+    /// that they will be orphans anymore.
+    pub(super) in_active_repeatable: bool,
     /// The span of the grid element.
     pub(super) span: Span,
 }
@@ -211,6 +221,7 @@ impl<'a> GridLayouter<'a> {
             upcoming_headers: &grid.headers,
             pending_headers: Default::default(),
             current_row_height: None,
+            in_active_repeatable: false,
             current: Current {
                 initial: regions.size,
                 repeated_header_rows: 0,
@@ -328,7 +339,9 @@ impl<'a> GridLayouter<'a> {
                     self.layout_relative_row(engine, disambiguator, v, y)?
                 }
                 Sizing::Fr(v) => {
-                    self.flush_orphans();
+                    if !self.in_active_repeatable {
+                        self.flush_orphans();
+                    }
                     self.lrows.push(Row::Fr(v, y, disambiguator))
                 }
             }
@@ -1441,9 +1454,11 @@ impl<'a> GridLayouter<'a> {
     /// will be pushed for this particular row. It can be `false` for rows
     /// spanning multiple regions.
     fn push_row(&mut self, frame: Frame, y: usize, is_last: bool) {
-        // There is now a row after the rows equipped with orphan prevention,
-        // so no need to remove them anymore.
-        self.flush_orphans();
+        if !self.in_active_repeatable {
+            // There is now a row after the rows equipped with orphan
+            // prevention, so no need to keep moving them anymore.
+            self.flush_orphans();
+        }
         self.regions.size.y -= frame.height();
         self.lrows.push(Row::Frame(frame, y, is_last));
     }

crates/typst-layout/src/grid/repeated.rs

@@ -57,11 +57,20 @@ impl<'a> GridLayouter<'a> {
         y: usize,
         engine: &mut Engine,
         disambiguator: usize,
+        as_short_lived: bool,
     ) -> SourceResult<Option<Abs>> {
         let previous_row_height =
             std::mem::replace(&mut self.current_row_height, Some(Abs::zero()));
+        let previous_in_active_repeatable =
+            std::mem::replace(&mut self.in_active_repeatable, !as_short_lived);
+
         self.layout_row(y, engine, disambiguator)?;
 
+        _ = std::mem::replace(
+            &mut self.in_active_repeatable,
+            previous_in_active_repeatable,
+        );
+
         Ok(std::mem::replace(&mut self.current_row_height, previous_row_height))
     }
 
@@ -73,11 +82,13 @@ impl<'a> GridLayouter<'a> {
         header: &Header,
         engine: &mut Engine,
         disambiguator: usize,
+        as_short_lived: bool,
     ) -> SourceResult<Abs> {
         let mut header_height = Abs::zero();
         for y in header.range() {
-            header_height +=
-                self.layout_header_row(y, engine, disambiguator)?.unwrap_or_default();
+            header_height += self
+                .layout_header_row(y, engine, disambiguator, as_short_lived)?
+                .unwrap_or_default();
         }
         Ok(header_height)
     }
@@ -270,7 +281,8 @@ impl<'a> GridLayouter<'a> {
         // 'layout_row' so this is fine.
         let mut i = 0;
         while let Some(&header) = self.repeating_headers.get(i) {
-            let header_height = self.layout_header_rows(header, engine, disambiguator)?;
+            let header_height =
+                self.layout_header_rows(header, engine, disambiguator, false)?;
             self.current.header_height += header_height;
             self.current.repeating_header_height += header_height;
 
@@ -307,7 +319,7 @@ impl<'a> GridLayouter<'a> {
 
         for header in self.pending_headers {
             let header_height =
-                self.layout_header_rows(header.unwrap(), engine, disambiguator)?;
+                self.layout_header_rows(header.unwrap(), engine, disambiguator, false)?;
             self.current.header_height += header_height;
             if matches!(header, Repeatable::Repeated(_)) {
                 self.current.repeating_header_height += header_height;
@@ -365,7 +377,8 @@ impl<'a> GridLayouter<'a> {
 
         let initial_row_count = self.lrows.len();
         for header in headers {
-            let header_height = self.layout_header_rows(header.unwrap(), engine, 0)?;
+            let header_height =
+                self.layout_header_rows(header.unwrap(), engine, 0, false)?;
 
             // Only store this header height if it is actually going to
             // become a pending header. Otherwise, pretend it's not a
@@ -483,10 +496,24 @@ impl<'a> GridLayouter<'a> {
         // anyway, so this is mostly for correctness.
         self.regions.size.y += self.current.footer_height;
 
+        let repeats = self
+            .grid
+            .footer
+            .as_ref()
+            .is_some_and(|f| matches!(f, Repeatable::Repeated(_)));
         let footer_len = self.grid.rows.len() - footer.start;
         self.unbreakable_rows_left += footer_len;
+
         for y in footer.start..self.grid.rows.len() {
+            let previous_in_active_repeatable =
+                std::mem::replace(&mut self.in_active_repeatable, repeats);
+
             self.layout_row(y, engine, disambiguator)?;
+
+            _ = std::mem::replace(
+                &mut self.in_active_repeatable,
+                previous_in_active_repeatable,
+            );
         }
 
         Ok(())

tests/suite/layout/grid/subheaders.typ

@@ -684,6 +684,17 @@
   grid.cell(x: 0)[end],
 )
 
+--- grid-subheaders-non-repeating-header-before-multi-page-row ---
+#set page(height: 6em)
+#grid(
+  grid.header(
+    repeat: false,
+    [h]
+  ),
+  [row #colbreak() row]
+)
+
+
 --- grid-subheaders-short-lived-no-orphan-prevention ---
 // No orphan prevention for short-lived headers.
 #set page(height: 8em)