Prevent paragraph from overflowing due to trailing linebreak

src/layout/grid.rs

@@ -179,8 +179,6 @@ impl<'a> GridLayouter<'a> {
         // Sum of fractions of all fractional tracks.
         let mut fr = Fractional::zero();
 
-
-
         // Resolve the size of all linear columns and compute the sum of all
         // fractional tracks.
         for (&col, rcol) in self.cols.iter().zip(&mut self.rcols) {

src/layout/par.rs

@@ -218,22 +218,26 @@ impl<'a> ParLayouter<'a> {
                 stack.constraints.max.y.set_min(stack.size.h + line.size.h);
                 stack.finish_region(ctx);
             }
+
             // If the line does not fit horizontally or we have a mandatory
             // line break (i.e. due to "\n"), we push the line into the
             // stack.
             if mandatory || !stack.regions.current.w.fits(line.size.w) {
-                stack.push(line);
                 start = end;
                 last = None;
 
+                stack.push(line);
                 stack.constraints.min.y = Some(stack.size.h);
 
                 // If there is a trailing line break at the end of the
                 // paragraph, we want to force an empty line.
                 if mandatory && end == self.bidi.text.len() {
-                    stack.push(LineLayout::new(ctx, &self, end .. end));
+                    let line = LineLayout::new(ctx, &self, end .. end);
+                    if stack.regions.current.h.fits(line.size.h) {
+                        stack.push(line);
                         stack.constraints.min.y = Some(stack.size.h);
                     }
+                }
             } else {
                 // Otherwise, the line fits both horizontally and vertically
                 // and we remember it.

src/layout/stack.rs

@@ -173,8 +173,7 @@ impl<'a> StackLayouter<'a> {
         let expand = self.expand;
         let used = self.used.to_size(self.block);
 
-        // Determine the stack's size dependening on whether the region is
+        // Determine the stack's size dependening on whether the region expands.
-        // fixed.
         let size = Size::new(
             if expand.x {
                 self.constraints.exact.x = Some(self.full.w);

tests/typ/layout/grid-5.typ

@@ -0,0 +1,11 @@
+
+---
+// Test that trailing linebreak doesn't overflow the region.
+#page(height: 2cm)
+#grid[
+  Hello \
+  Hello \
+  Hello \
+
+  World
+]