Avalonia: Broken text wrapping in grid column

[MonkAlex]

  <Grid ColumnDefinitions="*, *">
    <TextBlock Grid.Column="1"
               VerticalAlignment="Center"
               Text="He determined to drop his litigation with the monastry, and relinguish his claims to the wood-cuting and fishery rihgts at once. He was the more ready to do this becuase the rights had becom much less valuable, and he had indeed the vaguest idea where the wood and river in quedtion were."
               TextWrapping="Wrap"/>
  </Grid>

[grokys]

@walterlv this looks like a Grid bug to me, do it look like a bug to you?

[Gillibald]

Will test this when I work on the new text layout. The only reason this could happen if the Grid isn't passing the correct boundaries to the TextBox(FormattedText). In theory this should happen to all kinds of controls. A border control with a defined border thickness and brush should also be cut off at the right side otherwise it's a bug related to the TextBox implementation.

[Gillibald]

My window has a size of (1920,1080) and the Grid tells the TextBox it has available space of (960,16) but the text layout has a height of 32 so one line is cut off. Somehow when you use VerticalAlignment="Center" the FormattedText doesn't get enough space. When VerticalAlignment="Stretch" is used everything works fine.

Update:

Okay, it seems that this cache has an old value.
https://github.com/AvaloniaUI/Avalonia/blob/master/src/Avalonia.Controls/Grid.cs#L315

When I debugged this I realized that the FormattedText is constructed twice. The first time the available space is infinity and the second time and old value of the cache.

Removing the caching fixes the issue. Every time a window is resized or shown the layout is calculated twice. The first time the grid passes the whole available space without column calculations and the second time with column calculations but with outdated cached desired size. The second layout pass should only be cached not the first one.

[grokys]

This appears to be caused by Grid caching the measurement of the child control, and applying that cache to subsequent measurements of a different size:

https://github.com/AvaloniaUI/Avalonia/blob/65234e8e43cdbff29791caecf224cbb4b05062be/src/Avalonia.Controls/Grid.cs#L317

[walterlv]

The new Grid measures the children by giving a positive infinity size and never measure them again so the TextBlock inside doesn't know the change of measured size.

Maybe the new Grid should measure the children again for some situations.