Unconstrained * rows/columns in Grid may expand when they should not

[hartez]

Given the following structure:

<VerticalStackLayout>
  <Grid RowDefinitions="*,*,*">
    <Label Text="Item 1" HeightRequest="35"/>
    <Label Text="Item 2" Grid.Row="1" HeightRequest="200"/>
    <Label Text="Item 3" Grid.Row="2" />
  </Grid>
</VerticalStackLayout>

Because the Grid is unconstrained vertically, the * rows should act as if they were Auto rows. Which means that the first row should have the height of the content (the 35 from the first Label). However, in some situations the logic which determines whether the * rows should expand to have matching size values will be triggered erroneously, and the rows will be expanded to consume the entire space with equal distribution. This happens when the cross-platform layout compares its measured size with the native platform's measurements and differences in architecture/rounding result in slightly different values.

We need to account for the rounding differences to avoid expanding these values erroneously. Possibly by introducing a tolerance value. Also, we need to determine whether decompression of * values should ever happen when the Grid is unconstrained in that direction; if not, then we can also avoid this situation by checking the initial measurement constraints when deciding whether to decompress the *'s.

[AmrAlSayed0]

I feel that with unconstrained Grids, star rows should take on the size of the largest star. For example, in the case you mentioned all rows would have a height of 200 since this still preserves the behavior of star rows/columns have set ratios between their lengths. In this case it's 1 but it could be anything.