fix for syntax measure

CHANGELOG.md

@@ -25,6 +25,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fix missing `mode` property on file wrapper breaking uploads via `requests` https://github.com/Textualize/rich/pull/2495
 - Fix mismatching default value of parameter `ensure_ascii` https://github.com/Textualize/rich/pull/2538
 - Remove unused height parameter in `Layout` class https://github.com/Textualize/rich/pull/2540
+- Fixed exception in Syntax.__rich_measure__ for empty files
 
 
 ### Changed

rich/syntax.py

@@ -593,10 +593,11 @@ class Syntax(JupyterMixin):
         if self.code_width is not None:
             width = self.code_width + self._numbers_column_width + padding + 1
             return Measurement(self._numbers_column_width, width)
+        lines = self.code.splitlines()
         width = (
             self._numbers_column_width
             + padding
-            + max(cell_len(line) for line in self.code.splitlines())
+            + (max(cell_len(line) for line in lines) if lines else 0)
         )
         if self.line_numbers:
             width += 1

tests/test_syntax.py

@@ -392,6 +392,9 @@ def test_syntax_measure():
     code = Syntax("Hello, World", "python", code_width=20, line_numbers=True)
     assert code.__rich_measure__(console, console.options) == Measurement(3, 24)
 
+    code = Syntax("", "python", code_width=20, line_numbers=True)
+    assert code.__rich_measure__(console, console.options) == Measurement(3, 24)
+
 
 if __name__ == "__main__":
     syntax = Panel.fit(