Fit minimal size of a QDockPanel after QLabel content update

I have a QDockWidget with a QGroupBox as the top widget, with QVBoxLayout applied. This contains a QChartView and a QLabel.

The QLabel contains a text composed of several lines of different length.

First, I would like to have the QChartView the same width and height as the QLabel.

Second, as the content of the QLabel is updated by setText(...) in a Slot method, its content changes in height and width. So I would like to update the width and height of the QChartView above it.

For the moment, I only achieved to grow the entire DockPanel to accomodate longer and wider QLabel content, but not to shrink back when this content is narrower and less wide...

I did play with a lot of things, without real success (here a snippet of the Slot method that updates the QLabel content...):

        self.fkChartView.hide()
        self.pPDetailsLabel.hide()
        self.pPDetailsLabel.parent().hide()
        self.pPDetailsLabel.setText(self.canvas.grayScottModel.getPearsonPatternDescription(specie=type))
        self.pPDetailsLabel.updateGeometry()
        self.pPDetailsLabel.parent().updateGeometry()
        self.pPDetailsLabel.parent().update()

        self.pPDetailsDock.updateGeometry()
        self.pPDetailsDock.update()

        self.pPDetailsLabel.show()
        self.pPDetailsLabel.parent().show()

        # print(self.pPDetailsLabel.sizeHint())
        self.fkChartView.setMinimumHeight(self.pPDetailsLabel.size().width())
        self.fkChartView.setMaximumHeight(self.pPDetailsLabel.size().width())
        self.fkChartView.setMinimumWidth(self.pPDetailsLabel.size().width())
        self.fkChartView.setMaximumWidth(self.pPDetailsLabel.size().width())
        self.fkChartView.updateGeometry()
        self.fkChartView.show()
        self.fkChartView.updateGeometry()
        self.fkChartView.update()

I tried to hide the widgets, so they forget their sizes and/or sizeHint (not sure). I tried a few updateGeometry() and update() too, but it does not seem to help.

An idea, anyone?

I had it working as intended in the end by doing this in the slot method that updates the content of the QLabel:

        self.fkChartView.hide()
        self.pPDetailsLabel.setText(self.canvas.grayScottModel.getPearsonPatternDescription(specie=type))
        self.pPDetailsLabel.adjustSize()
        self.pPDetailsLabel.parent().adjustSize()
        # Sets the dimensions of the chart folowing the label width
        self.fkChartView.setMinimumHeight(self.pPDetailsLabel.size().width())
        self.fkChartView.setMaximumHeight(self.pPDetailsLabel.size().width())
        self.fkChartView.setMinimumWidth(self.pPDetailsLabel.size().width())
        self.fkChartView.setMaximumWidth(self.pPDetailsLabel.size().width())
        self.fkChartView.adjustSize()
        self.fkChartView.show()
        self.pPDetailsDock.adjustSize()

So I first hide the QChartView, so its dimensions do not interfere, then all the magic happens thanks to the adjustSize() call. I do this on the QLabel after its content has been updated, then on its parent (the top QGroupBox in my QDockWidget). The QChartView still hidden, I force its dimensions, then show it and finally adjust the size of the QDockWidget.

It does precisely what I want: if text is broader, the chart expands but stays square, if text is narrower, chart shrinks, but stays square. Total height of the dock adjusts also to fit, without staying the longer and longer it had to be to accomodate for a big former QLabel content.