Repro steps:

  test('empty paragraph is empty', () {
    final TextPainter painter = TextPainter(
      textDirection: TextDirection.ltr,
      text: const TextSpan(),
    )..layout();

    expect(painter.computeLineMetrics(), isEmpty);
  });

Run flutter test test/painting/text_painter_test.dart --platform=chrome --web-renderer=html --plain-name='empty paragraph is empty'

it fails with error message:

Expected: empty
Actual: [
  EngineLineMetrics:LineMetrics(hardBreak: true, ascent: 10, descent: 4, unscaledAscent: 10, height: 14, width: 0, left: 0, baseline: 10, lineNumber: 0)
]

The behavior is reasonable but it's inconsistent with what SkParagraph reports.