Which use case are ou trying to solve with this? There is a limit to how small you can make a column, so after a certain threshold this wouldn't make any sense anymore and become borderline usable (see screenshot):

It would honestly make more sense to define a default width, or simply run the autosizing on mount

@michelengelen. i'm trying resolve next:
At first load, all table columns must be fit in screen width, like on the image below. It doesn't matter, what is inside the row.

When i press "Autosize columns", every column width arranges, as so content of column become fully visible, with horizontal scroll bar.

I think, it might be solved with new one property of GridAutosizeOptions, includeContent: false (default true)
But now, i'm trying resolve it with existing methods.

@A-Degtyarev I got what you are trying to do ... I just feel that it does not make that much sense, that's why I was asking what exact problem you are trying to solve here. Or to put it more specific: Why do the columns need to fit in the width of the data grid on first render?

@michelengelen , I solved my task with ref, state and setting up flex:0 in new State: look at my example in the 1st post.
But i think, that this solution is not pretty.

It's still not making any sense to me why you have to do that, but ok.
I am almost certain that this is not possible with the given methods of the grid atm, but let's ask the team: @mui/xgrid thoughts?

I don't think column autosizing not working with flex columns was intentional.
It should rather behave like regular resizing – once the column's dimension is changed, the flex for this column is ignored.

@romgrk any objections to making autosizing work with flex columns?

No objection.