ShapedText::push_hyphen: Use self.base for default hyphen range (#2299)

In the unlikely chance that we hyphenate after an empty line, we
set the glyph range to self.base..self.base so that subtracting

Fixes #2283.

crates/typst-library/src/text/shaping.rs

@@ -446,7 +446,12 @@ impl<'a> ShapedText<'a> {
                 .glyphs
                 .last()
                 .map(|g| g.range.end..g.range.end)
-                .unwrap_or_default();
+                // In the unlikely chance that we hyphenate after an
+                // empty line, ensure that the glyph range still falls
+                // after self.base so that subtracting either of the
+                // endpoints by self.base doesn’t underflow.
+                // See <https://github.com/typst/typst/issues/2283>.
+                .unwrap_or_else(|| self.base..self.base);
             self.width += x_advance.at(self.size);
             self.glyphs.to_mut().push(ShapedGlyph {
                 font,

tests/typ/text/shaping.typ

@@ -26,3 +26,9 @@ ABCअपार्टमेंट
 // doesn't exist in shaping output.
 #set text(dir: rtl, font: "Noto Serif Hebrew")
 \ ט
+
+---
+// Test that #2283 is fixed.
+#set text(font: "test", lang: "de", hyphenate: true, fallback: false)
+#set par(linebreaks: "simple")
+- ensure